[RBW] Re: AR front brake shudder and fork flex
I had a set or Ribbit (typical Cyclocross brakes, Mafac copies) on my Atlantis that did a very similar thing. I am not familiar with Paul's brakes so this may not apply (some brakes have an internal bushing and don't have a bushing riding directly on the cantilever post on the frame). Also Jim may be entirely correct in his explanation; without researching on the internet my mind took me down a different path. After fiddling around with the usual things, I noticed the Ribbits had a lot of clearance between the cantilever post on the fork and the inside diameter of the bushing in the brakes (a loose fit on the posts). This allowed the toe to change; as the brakes were applied the the force on the pads took up the clearance between the posts and the brakes tending to rotate the brakes to a toe-out position. I changed to Shimano XT High Profile cantilevers (which have very little slop) and the problem stopped completely. Sometimes more toe than seems reasonable can help shuddering brakes; some things flex more than we would like to believe. I tend to run the straddle cables quite high, the Shimanos on the Atlantis I have the straddle cable about 1/2 above the lower headset cup. The Mafacs on the Quickbeam the straddle cable is a few inches above the lower headset cup. Makes for a very firm feel at the brake lever. Angus On Feb 18, 9:09 pm, rw1911 rw1...@gmail.com wrote: I'm assuming (hoping) this is a simple setup issue... I've recently installed Paul brakes (neo-retro front, touring rear) on my relatively new to me 700c All-Rounder. The rears are wonderful, if not too powerful... I can skid at will. However, I'm experiencing extreme shudder and fork flex on the front. The headset is tight and the pads are toe'd to contact forward. Under low to medium speed braking, I can see/feel the fork flex (a lot!) and shudder. The straddle cable is set at about the top third of the lower headset cup. I've cleaned the rim and while it has gotten slightly better with use, is this a matter of adjustment or is the neo- retro too powerful? One thing I noticed during installation is that the Paul brakes sit a good bit higher on the studs than the Shimano's they replaced. Could this be contributing to the flex in the mounting studs and/or fork? Any experience/advice is appreciated. -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] AR front brake shudder and fork flex
Jim -- Would you lease elaborate no this paragraph that you just posted? I'd like to understand this issue, also. Here's the graph: Take a look at the thickness of the hanger - if it's a less expensive stamped piece, you might try a thicker part. Also, pay attention to the fit of the ferrule on the cable end. If there's movement there, that will tend to exacerbate it. From: CycloFiend cyclofi...@earthlink.net To: rbw-owners-bunch@googlegroups.com Sent: Fri, February 18, 2011 11:56:27 PM Subject: Re: [RBW] AR front brake shudder and fork flex on 2/18/11 7:09 PM, rw1911 at rw1...@gmail.com wrote: I've recently installed Paul brakes (neo-retro front, touring rear) on my relatively new to me 700c All-Rounder. The rears are wonderful, if not too powerful... I can skid at will. However, I'm experiencing extreme shudder and fork flex on the front. The headset is tight and the pads are toe'd to contact forward. Under low to medium speed braking, I can see/feel the fork flex (a lot!) and shudder. The straddle cable is set at about the top third of the lower headset cup. I've cleaned the rim and while it has gotten slightly better with use, is this a matter of adjustment or is the neo- retro too powerful? This has cropped up on CX boards (and maybe iBob - too late to skim the archives there). The working theory (which seems pretty salient) is that flex in the hanger tends causing the shuddering. There's really two separate issues going on - the fork flex you are seeing and the shuddering of the brakes. With averagely strong brakes, you will generally see some flexing of the blades. More than likely, you don't notice it until the shuddering starts, but the two aren't necessarily linked. Take a look at the thickness of the hanger - if it's a less expensive stamped piece, you might try a thicker part. Also, pay attention to the fit of the ferrule on the cable end. If there's movement there, that will tend to exacerbate it. As you clamp down and the pads clench, if the hanger flexes, it will lessen the pressure on the brake pads. Less pressure on the pad causes the hanger to straighten applying more pressure to the pad, which causes the hanger to flex again... kind of similar to the anti-lock brake shudder you get on an auto. The neo-retros are pretty powerful, so you are probably getting a bit more oomph from the system. You might try adjusting the brakes so you get a bit less leverage on them. Sheldon shows the variables - http://sheldonbrown.com/cantilever-adjustment.html hope that helps. -- Jim Edgar cyclofi...@earthlink.net ³Velvet pillows, safari parks, sunglasses: people have become woolly mice. They still have bodies that can walk for five days and four nights through a desert of snow, without food, but they accept praise for having taken a one-hour bicycle ride.² - Tim Krabbe, The Rider Cyclofiend Bicycle Photo Galleries - http://www.cyclofiend.com Current Classics - Cross Bikes Singlespeed - Working Bikes Send In Your Photos! - Here's how: http://www.cyclofiend.com/guidelines -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en. -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: AR front brake shudder and fork flex
My experience is the same as Angus's. My CR720's fit very loosely on the studs and when the pads contact the rim they pivot on the studs enough to go toe out if you do not set up the pads to be toe-in under contact and rotational load. Cured the violent low-speed shudder for me. -Mike C On Feb 19, 7:55 am, Angus angusle...@sbcglobal.net wrote: I had a set or Ribbit (typical Cyclocross brakes, Mafac copies) on my Atlantis that did a very similar thing. I am not familiar with Paul's brakes so this may not apply (some brakes have an internal bushing and don't have a bushing riding directly on the cantilever post on the frame). Also Jim may be entirely correct in his explanation; without researching on the internet my mind took me down a different path. After fiddling around with the usual things, I noticed the Ribbits had a lot of clearance between the cantilever post on the fork and the inside diameter of the bushing in the brakes (a loose fit on the posts). This allowed the toe to change; as the brakes were applied the the force on the pads took up the clearance between the posts and the brakes tending to rotate the brakes to a toe-out position. I changed to Shimano XT High Profile cantilevers (which have very little slop) and the problem stopped completely. Sometimes more toe than seems reasonable can help shuddering brakes; some things flex more than we would like to believe. I tend to run the straddle cables quite high, the Shimanos on the Atlantis I have the straddle cable about 1/2 above the lower headset cup. The Mafacs on the Quickbeam the straddle cable is a few inches above the lower headset cup. Makes for a very firm feel at the brake lever. Angus On Feb 18, 9:09 pm, rw1911 rw1...@gmail.com wrote: I'm assuming (hoping) this is a simple setup issue... I've recently installed Paul brakes (neo-retro front, touring rear) on my relatively new to me 700c All-Rounder. The rears are wonderful, if not too powerful... I can skid at will. However, I'm experiencing extreme shudder and fork flex on the front. The headset is tight and the pads are toe'd to contact forward. Under low to medium speed braking, I can see/feel the fork flex (a lot!) and shudder. The straddle cable is set at about the top third of the lower headset cup. I've cleaned the rim and while it has gotten slightly better with use, is this a matter of adjustment or is the neo- retro too powerful? One thing I noticed during installation is that the Paul brakes sit a good bit higher on the studs than the Shimano's they replaced. Could this be contributing to the flex in the mounting studs and/or fork? Any experience/advice is appreciated.- Hide quoted text - - Show quoted text - -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] AR front brake shudder and fork flex
Jim -- Disregard prior request for follow-up comment (unless you don't mind). I think I understand now after reading the Shelson piece several times. Thanks for the link. From: CycloFiend cyclofi...@earthlink.net To: rbw-owners-bunch@googlegroups.com Sent: Fri, February 18, 2011 11:56:27 PM Subject: Re: [RBW] AR front brake shudder and fork flex on 2/18/11 7:09 PM, rw1911 at rw1...@gmail.com wrote: I've recently installed Paul brakes (neo-retro front, touring rear) on my relatively new to me 700c All-Rounder. The rears are wonderful, if not too powerful... I can skid at will. However, I'm experiencing extreme shudder and fork flex on the front. The headset is tight and the pads are toe'd to contact forward. Under low to medium speed braking, I can see/feel the fork flex (a lot!) and shudder. The straddle cable is set at about the top third of the lower headset cup. I've cleaned the rim and while it has gotten slightly better with use, is this a matter of adjustment or is the neo- retro too powerful? This has cropped up on CX boards (and maybe iBob - too late to skim the archives there). The working theory (which seems pretty salient) is that flex in the hanger tends causing the shuddering. There's really two separate issues going on - the fork flex you are seeing and the shuddering of the brakes. With averagely strong brakes, you will generally see some flexing of the blades. More than likely, you don't notice it until the shuddering starts, but the two aren't necessarily linked. Take a look at the thickness of the hanger - if it's a less expensive stamped piece, you might try a thicker part. Also, pay attention to the fit of the ferrule on the cable end. If there's movement there, that will tend to exacerbate it. As you clamp down and the pads clench, if the hanger flexes, it will lessen the pressure on the brake pads. Less pressure on the pad causes the hanger to straighten applying more pressure to the pad, which causes the hanger to flex again... kind of similar to the anti-lock brake shudder you get on an auto. The neo-retros are pretty powerful, so you are probably getting a bit more oomph from the system. You might try adjusting the brakes so you get a bit less leverage on them. Sheldon shows the variables - http://sheldonbrown.com/cantilever-adjustment.html hope that helps. -- Jim Edgar cyclofi...@earthlink.net ³Velvet pillows, safari parks, sunglasses: people have become woolly mice. They still have bodies that can walk for five days and four nights through a desert of snow, without food, but they accept praise for having taken a one-hour bicycle ride.² - Tim Krabbe, The Rider Cyclofiend Bicycle Photo Galleries - http://www.cyclofiend.com Current Classics - Cross Bikes Singlespeed - Working Bikes Send In Your Photos! - Here's how: http://www.cyclofiend.com/guidelines -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en. -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] What's diff between Sackville olive and grey-grid fabrics?
Have searched for answer on RBW site without luck (but I'm not a real good searcher), and I'm not quite ready to call and bug someone there. Would rather bug all of you first! Sorry, and thanks. -- Forrest (in tropical Iowa City) -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Paul Jono Hub
On Feb 18, 6:49 pm, benzzoy benz...@yahoo.com wrote: On Feb 17, 9:02 pm, bfd bfd...@gmail.com wrote: On Feb 17, 8:28 pm, benzzoy benz...@yahoo.com wrote: I don't know if it's solely about the over locknut dimension. Except for most Shimano cassette hubs, all other cassette hubs also have the right side bearings (that supports the hub body) very close to the centerline of the axle. You appear to have missed it, but we're talking about FREEWHEEL rear hub, not cassette hubs! I don't think I missed it. I was specifically addressing the quote that the axle breakage of the C-Record hubs was due to it having an extended unsupported section. I refuted that by citing that axles do not break nowadays, whether they are extended or not, as verified by Shimano's outboard and other inboard designs. I insinuated that if the axle design is adequate (stronger material, bigger dimensions, etc), one could have an extended unsupported axle without axle breakage issues. Peter Chisolm (sp?), aka qui si parla campagnolo, agrees with you as he statedthe (C-Record) hub design was essentially the same (as the NR), the axles and overhang was larger on C Record since it was 7s(126mm), with NR often being 5/6s(120mm). Biggest reason axles break is misaligned frame dropouts. I use C Record hubs exclusively, adjust the drive side axle end to be the minimum length required for a DA 7s freewheel and don't break axles(I'm .1 offa ton). I think if the driveside length is kept to a minimum and the frame dropourts are aligned, you won't break axles. Again, my experience was 3 broken axles - 2 Campy, 1 Wheel Mfrg in about a 2 or 3 year period. With either Campy or Shimano cassette hubs, no problem. As an aside, Shimano's outboard design may be superior, but is it necessary? It may not be necessary, but the outboard bearing design allows Shimano to use a smaller axle without the risk of breakage. All current non-Shimano hubs that I know of do not use the Shimano design, even though the patent is likely expired. I'm curious as to why that is. Is it more expensive? Perhaps the reason most non-Shimano hubs didn't use Shimano design was because they didn't want to pay royalties? If these companies had used it, the cost would have been more expensive due to the royalty payments. Alternatively, it is possible that some companies approached Shimano about using the design and were denied. Shimano did this with its octalink bb. There are many companies out there who make cranksets with octalink fittings, as oppose to square taper or outboard bearings, but almost none who made octalink bb. Even Shimano itself went to the inboard design briefly for one model of the Dura Ace hubs (7850?) but it's back to the outboard design. The DA 7800 rear hub had the inboard bearing design. It looked like an exact copy of Campy's rear hub! The complaints that it was limited to only 10 speed cassette, no backward compatibility was one reason why Shimano went back to its outboard design. Good Luck! -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: AR front brake shudder and fork flex
This topic comes up repeatedly. The discussions typically focus on treatment, which is natural, because you just want the thing to go away. But understanding the cause is usually helpful in figuring out the treatment. The cause is as follows: You grab your front brake, which tries to stop the wheel rotating. The road is pushing back on your tire and your body's forward momentum is pushing forward on the front hub. This moment tries to bend back the front fork. You can do this part for yourself in the garage. Lock up the front brake and push forward on the bike. Everyone with me? Cool. Now look at the cable. The length of cable going from the hanger down to the brake is hanging in space in FRONT of the fork which is flexing BACK. The distance the cable spans is increasing, effectively making the cable shorter, which is going to tighten the front brake, the same way tightening your grip would have. This makes the force at the fork greater, flexing it more, tightening the brake more, and so on. This is a positive feedback that only stops when something lets go, and on the road, the thing that lets go is the road/tire interface. The tire momentarily lets go of the road, and the fork springs back forward which loosens the brake. When the tire hits the ground again it starts up all over again. This is the process, and it's not as well known as it should be. Forks with more flex and grabbier brakes exacerbate this. Extreme toe in techniques work because they make the brakes less grabby. Others have success with other brake pad compounds. I ran ceramic rims on a cross bike for just this reason, since ceramics and their associated green brake pads offer a very smoothly modulating brake surface. They almost never grab. A brake booster would only help to the extent that it keeps toed in pads from flattening out. In that way, the booster kind of acts as a de-booster, since it keeps the brakes from being too powerful. The thing that is common to most of our Rivendells is an extremely tall head tube and consequently a really long cable run from hanger to brake. The other very common technique to address this is to make that run of cable as short as possible by using a fork crown hanger. Now most of that cable run down to the hanger is housing, which flexes along with the fork and doesn't tighten the cable. I put a crown hanger on the Bombadil for exactly this reason. Mounting the hanger here takes any flex of the steerer and the crown out of the equation. It's now only flexing of the blades from the crown down to the brake posts that will feed into the tightening/flexing/tightening feedback. One of the old sages wrote on this on the internet. I don't remember if it was Jobst or Qvale or another one of the masters. That's where I learned about it. Here's a photo of that hanger setup: http://www.flickr.com/photos/45758191@N04/5236889932/ On Feb 19, 6:27 am, Ray Shine r.sh...@sbcglobal.net wrote: Jim -- Disregard prior request for follow-up comment (unless you don't mind). I think I understand now after reading the Shelson piece several times. Thanks for the link. From: CycloFiend cyclofi...@earthlink.net To: rbw-owners-bunch@googlegroups.com Sent: Fri, February 18, 2011 11:56:27 PM Subject: Re: [RBW] AR front brake shudder and fork flex on 2/18/11 7:09 PM, rw1911 at rw1...@gmail.com wrote: I've recently installed Paul brakes (neo-retro front, touring rear) on my relatively new to me 700c All-Rounder. The rears are wonderful, if not too powerful... I can skid at will. However, I'm experiencing extreme shudder and fork flex on the front. The headset is tight and the pads are toe'd to contact forward. Under low to medium speed braking, I can see/feel the fork flex (a lot!) and shudder. The straddle cable is set at about the top third of the lower headset cup. I've cleaned the rim and while it has gotten slightly better with use, is this a matter of adjustment or is the neo- retro too powerful? This has cropped up on CX boards (and maybe iBob - too late to skim the archives there). The working theory (which seems pretty salient) is that flex in the hanger tends causing the shuddering. There's really two separate issues going on - the fork flex you are seeing and the shuddering of the brakes. With averagely strong brakes, you will generally see some flexing of the blades. More than likely, you don't notice it until the shuddering starts, but the two aren't necessarily linked. Take a look at the thickness of the hanger - if it's a less expensive stamped piece, you might try a thicker part. Also, pay attention to the fit of the ferrule on the cable end. If there's movement there, that will tend to exacerbate it. As you clamp down and the pads clench, if the hanger flexes, it will lessen the pressure on the brake pads. Less pressure on the pad causes the hanger to straighten applying more pressure to
[RBW] Re: AR front brake shudder and fork flex
On Feb 19, 2011, at 1:56 AM, CycloFiend wrote: on 2/18/11 7:09 PM, rw1911 at rw1...@gmail.com wrote: I've recently installed Paul brakes (neo-retro front, touring rear) on my relatively new to me 700c All-Rounder. The rears are wonderful, if not too powerful... I can skid at will. However, I'm experiencing extreme shudder and fork flex on the front. The headset is tight and the pads are toe'd to contact forward. Under low to medium speed braking, I can see/feel the fork flex (a lot!) and shudder. The straddle cable is set at about the top third of the lower headset cup. I've cleaned the rim and while it has gotten slightly better with use, is this a matter of adjustment or is the neo- retro too powerful? This has cropped up on CX boards (and maybe iBob - too late to skim the archives there). The working theory (which seems pretty salient) is that flex in the hanger tends causing the shuddering. Flex in what hanger? Do you mean the one that connects the brake cable to the straddle wire? If so that's very likely to be a red herring IMHO. It's too small compared to the thickness of the metal to flex significantly. This is more or less typical in bikes with cantilevers and light road forks. It's one of the reasons that old MTBs with rigid forks had such big fork legs. The worst fork judder I ever saw was my friend Steve's Specialized S-Works from the early 90s; it had a really light road type fork and shook to beat the band on any braking at all. The bike weighed about 20 lbs but that was the tradeoff. My StumpJumper with suspension fork had no fork judder, but the fork was massive and there was a brake booster. Steve put a brake booster on his S-Works and it stopped the problem. The shudder is caused by stick-slip as the rim passes through the pads and the main issue there is fork flex (so long as the rim is clean and the pads are in good shape). Using a brake booster constrains the lateral motion of the cantilever studs as the fork flexes and stops the judder. On my 26 A/R I use a Nitto Mini front rack and that seems to stiffen things up enough that there is no fork judder under any kind of braking. I don't remember if there was any problem with this before I installed the rack, it's been on there about 10 years. My CX bike has some of this but it doesn't bother me enough to put a brake booster on it. The geometry of the brake itself, how much it flexes, how much play there is on the post, etc. are also likely to be contributors. To sum up my recommendations: 1. Clean the rim to make sure there are no sticky or slipper spots on the braking surface (the OP said that he did this). Also check the rim joint to make sure there is not a bump there which initiates the problem- if so, file the joint smooth. 2. Clean the surface of the brake pads with a file or sandpaper. Check toe-in to make sure this is correct. 3. Check to make sure the retaining bolts are properly tightened and that there is minimal play of the brake on the braze-on post (putting a thin washer between the bolt and the brake may be necessary- do not put it behind the brake, though- you don't want to move the brake away from the fork). 4. If those don't fix it, stiffen the front end with a brake booster or something like a Nitto Mini (if it fits) or a Mark's Rack. The Nitto Mini will be stiffer and more likely to be useful in this regard because of the way it mounts to the fork crown, but it may not fit the bike. Rivendell can advise. -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Paul Jono Hub
On Feb 18, 7:04 pm, EricP ericpl...@aol.com wrote: Interesting. As in the 1980's I often could bend oversized solid axles. As in the ones with flats on two sides to fit in the dropouts. Then it was purely the metal quality. Cro-mo versus mild steel. May be it was metal quality. I never broke or don't know of anyone who broke or bend NR axles. However, I broke 3 axles - 2 Campy, 1 Wheel Mfrg - on my early 90s C-Record rear hub. It might have been poor metal quality, misaligned dropouts (hard to align as my frame was carbon), or that I was running a 7 speed fw instead of 5/6 that were used on the NR hubs. As to Campy, only have a passing knowledge of the brand. My actual ownership has been limited to a peanut butter wrench. They don't make items I've generally been interested in using. Campy products are usually very well made. On occasions, their functionality or execution have not been up to standard - think delta brakes and synchro shifters - but their hubs were never a problem. The current generation of cassette hubs from 1999 to present have an oversized axle. That makes up for the weaker inboard bearing design. Nevertheless, you don't hear about axles breaking or bending. So, I suspect the oversized axles is the key. Same with PW fw hubs, it uses an oversized axle and you don't hear about Phil axles bending or breaking. Good Luck! -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Tapping Bleriot brake bridge
Hey folks- Now that the white and red Hetres are back in stock I'm getting the itch to try them. I want to maximize clearance so it looks like that would be the best approach. Would it be easy or advised to do this? I could call up Bilenky since they're local but I wanted to get opinions here. Also: best fenders for Bleriot + Hetre? I'm partial to Berthoud but open to VO and Honjo also. Thanks! -Justin -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Paul Jono Hub
This is one of those this is why we miss Sheldon conversations. -Justin Pick up some Sheldon fender nuts today August On Feb 19, 12:43 pm, bfd bfd...@gmail.com wrote: On Feb 18, 7:04 pm, EricP ericpl...@aol.com wrote: Interesting. As in the 1980's I often could bend oversized solid axles. As in the ones with flats on two sides to fit in the dropouts. Then it was purely the metal quality. Cro-mo versus mild steel. May be it was metal quality. I never broke or don't know of anyone who broke or bend NR axles. However, I broke 3 axles - 2 Campy, 1 Wheel Mfrg - on my early 90s C-Record rear hub. It might have been poor metal quality, misaligned dropouts (hard to align as my frame was carbon), or that I was running a 7 speed fw instead of 5/6 that were used on the NR hubs. As to Campy, only have a passing knowledge of the brand. My actual ownership has been limited to a peanut butter wrench. They don't make items I've generally been interested in using. Campy products are usually very well made. On occasions, their functionality or execution have not been up to standard - think delta brakes and synchro shifters - but their hubs were never a problem. The current generation of cassette hubs from 1999 to present have an oversized axle. That makes up for the weaker inboard bearing design. Nevertheless, you don't hear about axles breaking or bending. So, I suspect the oversized axles is the key. Same with PW fw hubs, it uses an oversized axle and you don't hear about Phil axles bending or breaking. Good Luck! -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: AR front brake shudder and fork flex
+1 for the fork crown hanger. Simplest fix. On Feb 19, 12:36 pm, William tapebu...@gmail.com wrote: This topic comes up repeatedly. The discussions typically focus on treatment, which is natural, because you just want the thing to go away. But understanding the cause is usually helpful in figuring out the treatment. The cause is as follows: You grab your front brake, which tries to stop the wheel rotating. The road is pushing back on your tire and your body's forward momentum is pushing forward on the front hub. This moment tries to bend back the front fork. You can do this part for yourself in the garage. Lock up the front brake and push forward on the bike. Everyone with me? Cool. Now look at the cable. The length of cable going from the hanger down to the brake is hanging in space in FRONT of the fork which is flexing BACK. The distance the cable spans is increasing, effectively making the cable shorter, which is going to tighten the front brake, the same way tightening your grip would have. This makes the force at the fork greater, flexing it more, tightening the brake more, and so on. This is a positive feedback that only stops when something lets go, and on the road, the thing that lets go is the road/tire interface. The tire momentarily lets go of the road, and the fork springs back forward which loosens the brake. When the tire hits the ground again it starts up all over again. This is the process, and it's not as well known as it should be. Forks with more flex and grabbier brakes exacerbate this. Extreme toe in techniques work because they make the brakes less grabby. Others have success with other brake pad compounds. I ran ceramic rims on a cross bike for just this reason, since ceramics and their associated green brake pads offer a very smoothly modulating brake surface. They almost never grab. A brake booster would only help to the extent that it keeps toed in pads from flattening out. In that way, the booster kind of acts as a de-booster, since it keeps the brakes from being too powerful. The thing that is common to most of our Rivendells is an extremely tall head tube and consequently a really long cable run from hanger to brake. The other very common technique to address this is to make that run of cable as short as possible by using a fork crown hanger. Now most of that cable run down to the hanger is housing, which flexes along with the fork and doesn't tighten the cable. I put a crown hanger on the Bombadil for exactly this reason. Mounting the hanger here takes any flex of the steerer and the crown out of the equation. It's now only flexing of the blades from the crown down to the brake posts that will feed into the tightening/flexing/tightening feedback. One of the old sages wrote on this on the internet. I don't remember if it was Jobst or Qvale or another one of the masters. That's where I learned about it. Here's a photo of that hanger setup: http://www.flickr.com/photos/45758191@N04/5236889932/ On Feb 19, 6:27 am, Ray Shine r.sh...@sbcglobal.net wrote: Jim -- Disregard prior request for follow-up comment (unless you don't mind). I think I understand now after reading the Shelson piece several times. Thanks for the link. From: CycloFiend cyclofi...@earthlink.net To: rbw-owners-bunch@googlegroups.com Sent: Fri, February 18, 2011 11:56:27 PM Subject: Re: [RBW] AR front brake shudder and fork flex on 2/18/11 7:09 PM, rw1911 at rw1...@gmail.com wrote: I've recently installed Paul brakes (neo-retro front, touring rear) on my relatively new to me 700c All-Rounder. The rears are wonderful, if not too powerful... I can skid at will. However, I'm experiencing extreme shudder and fork flex on the front. The headset is tight and the pads are toe'd to contact forward. Under low to medium speed braking, I can see/feel the fork flex (a lot!) and shudder. The straddle cable is set at about the top third of the lower headset cup. I've cleaned the rim and while it has gotten slightly better with use, is this a matter of adjustment or is the neo- retro too powerful? This has cropped up on CX boards (and maybe iBob - too late to skim the archives there). The working theory (which seems pretty salient) is that flex in the hanger tends causing the shuddering. There's really two separate issues going on - the fork flex you are seeing and the shuddering of the brakes. With averagely strong brakes, you will generally see some flexing of the blades. More than likely, you don't notice it until the shuddering starts, but the two aren't necessarily linked. Take a look at the thickness of the hanger - if it's a less expensive stamped piece, you might try a thicker part. Also, pay attention to the fit of the ferrule on the cable end. If there's movement there, that will tend to exacerbate it. As you
Re: [RBW] Tapping Bleriot brake bridge
On Sat, 2011-02-19 at 09:57 -0800, Justin August wrote: Hey folks- Now that the white and red Hetres are back in stock I'm getting the itch to try them. I want to maximize clearance so it looks like that would be the best approach. Would it be easy or advised to do this? I don't understand. I have a friend who runs Hetres on her Bleriot with no modifications at all. -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: On shipping bike parts to our two finest states
Grant For us east-coasters, would it be possible to at least offer the option of USPS? It's not a matter of cost as much as speed, at least for me, though it seems like anything I order costs $15 to ship, regardless, and paying for express shipping us a deal-killer. The real killer us that UPS is seven full days from CA to CT. That means if I decide I want or need something on a weekend and order it online, it ships that Monday but I don't even receive it in time for the next weekend, as it arrives the Monday after the Monday it ships. USPS is usually about 3 days coast to coast for reasonable size things. Just a thought. I'd like to buy more from Riv but I'm an instant gratification kind of guy! Pete On Feb 18, 7:00 pm, grant grant...@gmail.com wrote: UPS charges us $8.08 for under-a-pound boxes to major metropolitan areas in California. If you live in a van down by the river, it costs (us) more. A typical box weight here is 5 pounds. To the midwest, it costs (us) about $11. Alaska and Hawaii cost more, for sure. I wish we could get around UPS, but the other companies (FedX, USPS) either charge more or don't have tracking. Plus, the shippers are now super close buddies with Barry, our UPS guy, and even if FEDX got cheaper, it would take quite the Venezuelan FedX account manageress to get Robert and Vaughn to voluntarily, willingly, switch from UPS. It's not impossible, but unlikely. Our flat rate of $8 is below our cost, but in my head I'm still a 13- year old ordering from L.L. Bean and paying nothing. Still, we may have to raise rates. The thing of it is, we don't sell anything ending in a 9, and that's what a dollar increase would be. Another dollar, and it's into the double-digits, which seems a lot higher. Eight is magic here, for now. G -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Tapping Bleriot brake bridge
I'm also looking for a cleaner attachment system for the fenders. What fenders/rear mounting does she use? -Justin On Feb 19, 1:06 pm, Steve Palincsar palin...@his.com wrote: On Sat, 2011-02-19 at 09:57 -0800, Justin August wrote: Hey folks- Now that the white and red Hetres are back in stock I'm getting the itch to try them. I want to maximize clearance so it looks like that would be the best approach. Would it be easy or advised to do this? I don't understand. I have a friend who runs Hetres on her Bleriot with no modifications at all. -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] Re: AR front brake shudder and fork flex
Someone Anonymous posted: I've recently installed Paul brakes (neo-retro front, touring rear) on my relatively new to me 700c All-Rounder. The rears are wonderful, if not too powerful... I can skid at will. However, I'm experiencing extreme shudder and fork flex on the front. To which I reply: I have Paul Touring brakes on my 26 version Allrounder. I don't have any shuddering issues. Maybe try putting the touring model on the front for a few rides and see if you still have the issue. If the shudder goes away or lessens, go with a matching set of Touring brakes. I'm sure you could find someone to take the spare Neo-Retro off your hands. Just a thought. -Mike in once again frigid So. Boston, Mass -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Tapping Bleriot brake bridge
Hey Justin, I use a pair a Sheldon Fender Nuts to attach the SKS fenders over the Hetres on my Bleriot. This works well with the L-bracket connection at the brake bridge. -Jay B On Feb 19, 10:57 am, Justin August justinaug...@gmail.com wrote: Hey folks- Now that the white and red Hetres are back in stock I'm getting the itch to try them. I want to maximize clearance so it looks like that would be the best approach. Would it be easy or advised to do this? I could call up Bilenky since they're local but I wanted to get opinions here. Also: best fenders for Bleriot + Hetre? I'm partial to Berthoud but open to VO and Honjo also. Thanks! -Justin -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Tapping Bleriot brake bridge
I'm picking up Sheldon nuts today for my Berthouds. May just stick with that. I'm just jealous of the clean lines from a tapped bridge! -Justin On Feb 19, 1:36 pm, J. Burkhalter burk...@yahoo.com wrote: Hey Justin, I use a pair a Sheldon Fender Nuts to attach the SKS fenders over the Hetres on my Bleriot. This works well with the L-bracket connection at the brake bridge. -Jay B On Feb 19, 10:57 am, Justin August justinaug...@gmail.com wrote: Hey folks- Now that the white and red Hetres are back in stock I'm getting the itch to try them. I want to maximize clearance so it looks like that would be the best approach. Would it be easy or advised to do this? I could call up Bilenky since they're local but I wanted to get opinions here. Also: best fenders for Bleriot + Hetre? I'm partial to Berthoud but open to VO and Honjo also. Thanks! -Justin -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] Re: AR front brake shudder and fork flex
Excellent explanation. Even I could make sense of it! Thank you! From: William tapebu...@gmail.com To: RBW Owners Bunch rbw-owners-bunch@googlegroups.com Sent: Sat, February 19, 2011 9:36:14 AM Subject: [RBW] Re: AR front brake shudder and fork flex This topic comes up repeatedly. The discussions typically focus on treatment, which is natural, because you just want the thing to go away. But understanding the cause is usually helpful in figuring out the treatment. The cause is as follows: You grab your front brake, which tries to stop the wheel rotating. The road is pushing back on your tire and your body's forward momentum is pushing forward on the front hub. This moment tries to bend back the front fork. You can do this part for yourself in the garage. Lock up the front brake and push forward on the bike. Everyone with me? Cool. Now look at the cable. The length of cable going from the hanger down to the brake is hanging in space in FRONT of the fork which is flexing BACK. The distance the cable spans is increasing, effectively making the cable shorter, which is going to tighten the front brake, the same way tightening your grip would have. This makes the force at the fork greater, flexing it more, tightening the brake more, and so on. This is a positive feedback that only stops when something lets go, and on the road, the thing that lets go is the road/tire interface. The tire momentarily lets go of the road, and the fork springs back forward which loosens the brake. When the tire hits the ground again it starts up all over again. This is the process, and it's not as well known as it should be. Forks with more flex and grabbier brakes exacerbate this. Extreme toe in techniques work because they make the brakes less grabby. Others have success with other brake pad compounds. I ran ceramic rims on a cross bike for just this reason, since ceramics and their associated green brake pads offer a very smoothly modulating brake surface. They almost never grab. A brake booster would only help to the extent that it keeps toed in pads from flattening out. In that way, the booster kind of acts as a de-booster, since it keeps the brakes from being too powerful. The thing that is common to most of our Rivendells is an extremely tall head tube and consequently a really long cable run from hanger to brake. The other very common technique to address this is to make that run of cable as short as possible by using a fork crown hanger. Now most of that cable run down to the hanger is housing, which flexes along with the fork and doesn't tighten the cable. I put a crown hanger on the Bombadil for exactly this reason. Mounting the hanger here takes any flex of the steerer and the crown out of the equation. It's now only flexing of the blades from the crown down to the brake posts that will feed into the tightening/flexing/tightening feedback. One of the old sages wrote on this on the internet. I don't remember if it was Jobst or Qvale or another one of the masters. That's where I learned about it. Here's a photo of that hanger setup: http://www.flickr.com/photos/45758191@N04/5236889932/ On Feb 19, 6:27 am, Ray Shine r.sh...@sbcglobal.net wrote: Jim -- Disregard prior request for follow-up comment (unless you don't mind). I think I understand now after reading the Shelson piece several times. Thanks for the link. From: CycloFiend cyclofi...@earthlink.net To: rbw-owners-bunch@googlegroups.com Sent: Fri, February 18, 2011 11:56:27 PM Subject: Re: [RBW] AR front brake shudder and fork flex on 2/18/11 7:09 PM, rw1911 at rw1...@gmail.com wrote: I've recently installed Paul brakes (neo-retro front, touring rear) on my relatively new to me 700c All-Rounder. The rears are wonderful, if not too powerful... I can skid at will. However, I'm experiencing extreme shudder and fork flex on the front. The headset is tight and the pads are toe'd to contact forward. Under low to medium speed braking, I can see/feel the fork flex (a lot!) and shudder. The straddle cable is set at about the top third of the lower headset cup. I've cleaned the rim and while it has gotten slightly better with use, is this a matter of adjustment or is the neo- retro too powerful? This has cropped up on CX boards (and maybe iBob - too late to skim the archives there). The working theory (which seems pretty salient) is that flex in the hanger tends causing the shuddering. There's really two separate issues going on - the fork flex you are seeing and the shuddering of the brakes. With averagely strong brakes, you will generally see some flexing of the blades. More than likely, you don't notice it until the shuddering starts, but the two aren't necessarily linked. Take a look at the thickness of the hanger - if it's a less expensive stamped piece, you might try a thicker part. Also, pay attention to the fit of
Re: [RBW] Re: Tapping Bleriot brake bridge
On Sat, 2011-02-19 at 10:28 -0800, Justin August wrote: I'm also looking for a cleaner attachment system for the fenders. What fenders/rear mounting does she use? Plastic SKS. -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: What's diff between Sackville olive and grey-grid fabrics?
Hey Forrest - I have an XS Saddlesack in olive and a ton of others in grid-grey (TourSack, ShopSack and on and on...). The olive material seems to be slightly thicker and stiffer - sort of a brushed cotton canvas type of material. The grey ones seem to be a little thinner and more flexible. They have a slicker feel to them as well and clean a little easier. I even washed my ShopSack in the washing machine once and it came out real soft and a little faded, looks and feels real good. But then what do I know - I'm a bag matcher. I like the look of the grid-grey more than the olive. Also, to Grant's post yesterday about the GrabSack being an unexpected poor seller: From the first day I got mine, I told everyone that this is the best bag in the world. By far my favorite bag of all time. So, again, what do I know. Heading out the door for S24O #2 of the year (goal for this year is 10) on the Atlantis!!! Going to scare the wildlife a bit and hope they don't scare back. Joel (When I grow up, I want to be just like me.) On Feb 19, 10:23 am, Forrest ftme...@me.com wrote: Have searched for answer on RBW site without luck (but I'm not a real good searcher), and I'm not quite ready to call and bug someone there. Would rather bug all of you first! Sorry, and thanks. -- Forrest (in tropical Iowa City) -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Tapping Bleriot brake bridge
The only potential problem I foresee is having enough thread in the boss for a secure attachment. There's not a whole lot of room under the bridge for a protruding braze-on (for lack of a better term), so you have the issue of being able to run the brake bolt through the bridge with the fender attachment bolt underneath. In any event you can't get much better advice than from Bilenky. :) Hetres are the best in my book. White Hetres are way cool. I'm getting another pair. I like the VO Zeppelin fenders. Ryan On Feb 19, 9:57 am, Justin August justinaug...@gmail.com wrote: Hey folks- Now that the white and red Hetres are back in stock I'm getting the itch to try them. I want to maximize clearance so it looks like that would be the best approach. Would it be easy or advised to do this? I could call up Bilenky since they're local but I wanted to get opinions here. Also: best fenders for Bleriot + Hetre? I'm partial to Berthoud but open to VO and Honjo also. Thanks! -Justin -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] Tapping Bleriot brake bridge
Hey Justin, I have a bleriot and run hetres with SKS p50 form Riv. I know theyre plastic, but Ive had some VO fenders and when the aluminum starts to ding its hard to readjust. The SKS's are way more solid and easier to set up in my opinion. No mods to the bike at all.good luck -Mike On Sat, Feb 19, 2011 at 9:57 AM, Justin August justinaug...@gmail.comwrote: Hey folks- Now that the white and red Hetres are back in stock I'm getting the itch to try them. I want to maximize clearance so it looks like that would be the best approach. Would it be easy or advised to do this? I could call up Bilenky since they're local but I wanted to get opinions here. Also: best fenders for Bleriot + Hetre? I'm partial to Berthoud but open to VO and Honjo also. Thanks! -Justin -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en. -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] Re: AR front brake shudder and fork flex
use a fork crown hanger. the tektros ones kinda suck, but the specialized ones are great. On Sat, Feb 19, 2011 at 12:51 PM, Ray Shine r.sh...@sbcglobal.net wrote: Excellent explanation. Even I could make sense of it! Thank you! -- *From:* William tapebu...@gmail.com *To:* RBW Owners Bunch rbw-owners-bunch@googlegroups.com *Sent:* Sat, February 19, 2011 9:36:14 AM *Subject:* [RBW] Re: AR front brake shudder and fork flex This topic comes up repeatedly. The discussions typically focus on treatment, which is natural, because you just want the thing to go away. But understanding the cause is usually helpful in figuring out the treatment. The cause is as follows: You grab your front brake, which tries to stop the wheel rotating. The road is pushing back on your tire and your body's forward momentum is pushing forward on the front hub. This moment tries to bend back the front fork. You can do this part for yourself in the garage. Lock up the front brake and push forward on the bike. Everyone with me? Cool. Now look at the cable. The length of cable going from the hanger down to the brake is hanging in space in FRONT of the fork which is flexing BACK. The distance the cable spans is increasing, effectively making the cable shorter, which is going to tighten the front brake, the same way tightening your grip would have. This makes the force at the fork greater, flexing it more, tightening the brake more, and so on. This is a positive feedback that only stops when something lets go, and on the road, the thing that lets go is the road/tire interface. The tire momentarily lets go of the road, and the fork springs back forward which loosens the brake. When the tire hits the ground again it starts up all over again. This is the process, and it's not as well known as it should be. Forks with more flex and grabbier brakes exacerbate this. Extreme toe in techniques work because they make the brakes less grabby. Others have success with other brake pad compounds. I ran ceramic rims on a cross bike for just this reason, since ceramics and their associated green brake pads offer a very smoothly modulating brake surface. They almost never grab. A brake booster would only help to the extent that it keeps toed in pads from flattening out. In that way, the booster kind of acts as a de-booster, since it keeps the brakes from being too powerful. The thing that is common to most of our Rivendells is an extremely tall head tube and consequently a really long cable run from hanger to brake. The other very common technique to address this is to make that run of cable as short as possible by using a fork crown hanger. Now most of that cable run down to the hanger is housing, which flexes along with the fork and doesn't tighten the cable. I put a crown hanger on the Bombadil for exactly this reason. Mounting the hanger here takes any flex of the steerer and the crown out of the equation. It's now only flexing of the blades from the crown down to the brake posts that will feed into the tightening/flexing/tightening feedback. One of the old sages wrote on this on the internet. I don't remember if it was Jobst or Qvale or another one of the masters. That's where I learned about it. Here's a photo of that hanger setup: http://www.flickr.com/photos/45758191@N04/5236889932/ On Feb 19, 6:27 am, Ray Shine r.sh...@sbcglobal.net wrote: Jim -- Disregard prior request for follow-up comment (unless you don't mind). I think I understand now after reading the Shelson piece several times. Thanks for the link. From: CycloFiend cyclofi...@earthlink.net To: rbw-owners-bunch@googlegroups.com Sent: Fri, February 18, 2011 11:56:27 PM Subject: Re: [RBW] AR front brake shudder and fork flex on 2/18/11 7:09 PM, rw1911 at rw1...@gmail.com wrote: I've recently installed Paul brakes (neo-retro front, touring rear) on my relatively new to me 700c All-Rounder. The rears are wonderful, if not too powerful... I can skid at will. However, I'm experiencing extreme shudder and fork flex on the front. The headset is tight and the pads are toe'd to contact forward. Under low to medium speed braking, I can see/feel the fork flex (a lot!) and shudder. The straddle cable is set at about the top third of the lower headset cup. I've cleaned the rim and while it has gotten slightly better with use, is this a matter of adjustment or is the neo- retro too powerful? This has cropped up on CX boards (and maybe iBob - too late to skim the archives there). The working theory (which seems pretty salient) is that flex in the hanger tends causing the shuddering. There's really two separate issues going on - the fork flex you are seeing and the shuddering of the brakes. With averagely strong brakes, you will generally see some flexing of the blades. More
[RBW] Re: AR front brake shudder and fork flex
Excellent explanation Jim. I've had the same problem with tektro 720's on my ti rando with a ti fork. I played with different hangers, longer stem cable stop, changed the height of the hanger to shorten the amount of exposed cable between the stem cable stop and the hanger, I've toed in my brake shoes, tried different brake shoes, made my brakes really weak and really strong. I still had shudder. I ended up switching to a very unattractive V-brake and dia compe 287 levers, the shudder disappeared completely. Like my friend Dave said, it is the exposed cable from the steerer tube cable stop to the hanger that is flexing, causing the pressure on the pads to the rim to change, increasing and decreasing pressure as the cable flexes. By eliminating that exposed cable, with the v-brake cable routing, the oscillating, pulsing shudder disappears. It worked for me anyways... -Ely On Feb 18, 11:56 pm, CycloFiend cyclofi...@earthlink.net wrote: on 2/18/11 7:09 PM, rw1911 at rw1...@gmail.com wrote: I've recently installed Paul brakes (neo-retro front, touring rear) on my relatively new to me 700c All-Rounder. The rears are wonderful, if not too powerful... I can skid at will. However, I'm experiencing extreme shudder and fork flex on the front. The headset is tight and the pads are toe'd to contact forward. Under low to medium speed braking, I can see/feel the fork flex (a lot!) and shudder. The straddle cable is set at about the top third of the lower headset cup. I've cleaned the rim and while it has gotten slightly better with use, is this a matter of adjustment or is the neo- retro too powerful? This has cropped up on CX boards (and maybe iBob - too late to skim the archives there). The working theory (which seems pretty salient) is that flex in the hanger tends causing the shuddering. There's really two separate issues going on - the fork flex you are seeing and the shuddering of the brakes. With averagely strong brakes, you will generally see some flexing of the blades. More than likely, you don't notice it until the shuddering starts, but the two aren't necessarily linked. Take a look at the thickness of the hanger - if it's a less expensive stamped piece, you might try a thicker part. Also, pay attention to the fit of the ferrule on the cable end. If there's movement there, that will tend to exacerbate it. As you clamp down and the pads clench, if the hanger flexes, it will lessen the pressure on the brake pads. Less pressure on the pad causes the hanger to straighten applying more pressure to the pad, which causes the hanger to flex again... kind of similar to the anti-lock brake shudder you get on an auto. The neo-retros are pretty powerful, so you are probably getting a bit more oomph from the system. You might try adjusting the brakes so you get a bit less leverage on them. Sheldon shows the variables - http://sheldonbrown.com/cantilever-adjustment.html hope that helps. -- Jim Edgar cyclofi...@earthlink.net ³Velvet pillows, safari parks, sunglasses: people have become woolly mice. They still have bodies that can walk for five days and four nights through a desert of snow, without food, but they accept praise for having taken a one-hour bicycle ride.² - Tim Krabbe, The Rider Cyclofiend Bicycle Photo Galleries -http://www.cyclofiend.com Current Classics - Cross Bikes Singlespeed - Working Bikes Send In Your Photos! - Here's how:http://www.cyclofiend.com/guidelines -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] AR front brake shudder and fork flex
on 2/19/11 5:56 AM, Ray Shine at r.sh...@sbcglobal.net wrote: Jim -- Would you lease elaborate no this paragraph that you just posted? I'd like to understand this issue, also. Here's the graph: Take a look at the thickness of the hanger - if it's a less expensive stamped piece, you might try a thicker part. Also, pay attention to the fit of the ferrule on the cable end. If there's movement there, that will tend to exacerbate it. Happy to try, Ray (and I apologize for any imperfections of language in advance): The cable and housing connect directly to the cable hanger. The cable hanger is sandwiched between the nuts on a traditional threaded stem. The contact point of the housing end to the hanger is an inch or so away from the base of the hanger. As additional force is applied at the brake lever, there is a potential for the hanger to flex downward toward the front tire. As the hanger flexes downward, it releases a very slight amount of cable tension with respect to the brakes themselves. This causes a micro-release of the brakes, and a resultant un-flexing of the hanger, which retensions the brakes. Cheaper hangers tend to be a stamped piece of metal which flex more. I've also seen ferrules grind away at the hanger, ovalising the contact area (ferrule on the cable end should fit firmly into the stop) or enlarging it so that there is a slight amount of play. I was really discusing two variables at the hanger - both the physical construction of the hanger itself, and any movement in how the cable housing is secured into it. hope that makes sense, - Jim -- Jim Edgar cyclofi...@earthlink.net Cyclofiend Bicycle Photo Galleries - http://www.cyclofiend.com Current Classics - Cross Bikes Singlespeed - Working Bikes Your Photos are needed! - Send them here - http://www.cyclofiend.com/guidelines I threw one leg over my battle-scarred all-terrain stump-jumper and rode several miles to work. I'd sprayed it with some cheap gold paint so it wouldn't look nice. Locked my bike to a radiator, because you never knew, and went in. -- Neal Stephenson, Zodiac -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] Re: AR front brake shudder and fork flex
On Feb 19, 2011, at 12:51 PM, Ray Shine wrote: Excellent explanation. Even I could make sense of it! Thank you! From: William tapebu...@gmail.com To: RBW Owners Bunch rbw-owners-bunch@googlegroups.com Sent: Sat, February 19, 2011 9:36:14 AM Subject: [RBW] Re: AR front brake shudder and fork flex This topic comes up repeatedly. The discussions typically focus on treatment, which is natural, because you just want the thing to go away. But understanding the cause is usually helpful in figuring out the treatment. The cause is as follows: You grab your front brake, which tries to stop the wheel rotating. The road is pushing back on your tire and your body's forward momentum is pushing forward on the front hub. This moment tries to bend back the front fork. You can do this part for yourself in the garage. Lock up the front brake and push forward on the bike. Everyone with me? Cool. Now look at the cable. The length of cable going from the hanger down to the brake is hanging in space in FRONT of the fork which is flexing BACK. The distance the cable spans is increasing, effectively making the cable shorter, which is going to tighten the front brake, the same way tightening your grip would have. This makes the force at the fork greater, flexing it more, tightening the brake more, and so on. So far so good. Except that you'd have to be flexing the fork between the brake pad contact point and the brake cable hanger on the top of the headset; this also requires flexing the steerer and possibly the head tube. That's not impossible, I suppose. I have read that steerers can flex in the lower part, near the lower headset race. Maybe that can flex enough. Or maybe there's enough flex in the fork legs between the braze-on and the bottom headset cups; you'd only need a little bit of stretch, maybe a mm or so, to significantly tighten the brake. The alternative is the fork legs twisting as the brake pads are dragged forward. Oval tubing is poorly resistant to being twisted (which is why ovalized down tubes don't stiffen the BB- they are twisted rather than loaded laterally. And why Ritchey ovalizes the seat tube, which is loaded laterally). My thought is that the pads are dragged forward until the front edge lifts enough that friction is reduced and the rim can slip; as the pads snap back they grab again and the cycle is repeated. This is why a brake booster works, it prevents the fork legs from being twisted by constraining the ends of the braze-ons from swinging away from the centerline. Even simpler is if there's a bump at the rim joint or a bump in the rim from an impact; that can cause this sort of thing. The visible process is the wagging of the forks as a symptom of the stick-slip cycle. It can be very dramatic- my friend Steve's S-works looked like the front end was going to fly apart. This is a positive feedback that only stops when something lets go, and on the road, the thing that lets go is the road/tire interface. The tire momentarily lets go of the road, and the fork springs back forward which loosens the brake. When the tire hits the ground again it starts up all over again. Here's where we run into problems with this explanation IMHO. Since you're decelerating, you're loading the front tire more heavily and pushing it against the ground. This makes it harder for the tire to skip. And, if this happened in a turn, you'd just crash. Besides, lifting the tire off the ground wouldn't loosen the pads by any mechanism I can think of right now. I could be quite wrong, of course. Wouldn't be the first time... -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] Re: AR front brake shudder and fork flex
on 2/19/11 9:43 AM, Tim McNamara at tim...@bitstream.net wrote: This has cropped up on CX boards (and maybe iBob - too late to skim the archives there). The working theory (which seems pretty salient) is that flex in the hanger tends causing the shuddering. Flex in what hanger? Do you mean the one that connects the brake cable to the straddle wire? If so that's very likely to be a red herring IMHO. It's too small compared to the thickness of the metal to flex significantly. The hanging cable stop which is usually sandwiched at the top of the headset on a traditional threaded fork. I'm not saying that's the only variable. Pad effectiveness, brake slop on the canti studs and brake leverage all can play a part as well. But, the Paul's brakes don't tend to flex too much, and they have a pretty good leverage. - Jim -- Jim Edgar cyclofi...@earthlink.net Cyclofiend Bicycle Photo Galleries - http://www.cyclofiend.com Current Classics - Cross Bikes Singlespeed - Working Bikes Gallery updates now appear here - http://cyclofiend.blogspot.com Nigel did some work for some of the other riders at Allied, onces who still rode metal. He hadn't liked it when Chevette had gone for a paper frame. -- William Gibson, Virtual Light -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: AR front brake shudder and fork flex
Tim If you think about it some more, I think you'll see it. The tire lifting off the ground un-flexes the fork, relaxing the cable tension and loosens the clamping force of the brakes on the rim. It can't be otherwise. Like a bow-and-arrow in reverse I'll go ahead and make a statement and claim it as fact and see if anyone can even anecdotally dispute it. We'll see where that takes us. Virtually everyone has seen, experienced or heard about this violent fore-aft shuddering on a bicycle under hard front braking. My claim is that every single one of them was a bike with cantilever brakes or center pull brakes. It doesn't happen with V brakes and it doesnt happen with caliper brakes, or disk brakes for that matter. That's because brakes with all-housing are immune to any flex-induced tensioning and detensioning of the cable. Canti-bikes and centerpull bikes don't HAVE to have this problem, but V-brake, disk brake, and caliper brake bikes can't have it. If this had to do with toed in brake pads micro gripping and releasing, it would be equally common on all rim brake types. Furthermore, there is no free-body diagram one could draw to claim that a brake caliper of any kind squeezing harder on a rim will result in the brake pad squeezing LESS hard on the rim and allow it to release. That's just not physically possible. The sliding rim sort of shrugging the brakepad off of it, like some little wrestling move doesn't hold up. On Feb 19, 1:33 pm, Tim McNamara tim...@bitstream.net wrote: On Feb 19, 2011, at 12:51 PM, Ray Shine wrote: Excellent explanation. Even I could make sense of it! Thank you! From: William tapebu...@gmail.com To: RBW Owners Bunch rbw-owners-bunch@googlegroups.com Sent: Sat, February 19, 2011 9:36:14 AM Subject: [RBW] Re: AR front brake shudder and fork flex This topic comes up repeatedly. The discussions typically focus on treatment, which is natural, because you just want the thing to go away. But understanding the cause is usually helpful in figuring out the treatment. The cause is as follows: You grab your front brake, which tries to stop the wheel rotating. The road is pushing back on your tire and your body's forward momentum is pushing forward on the front hub. This moment tries to bend back the front fork. You can do this part for yourself in the garage. Lock up the front brake and push forward on the bike. Everyone with me? Cool. Now look at the cable. The length of cable going from the hanger down to the brake is hanging in space in FRONT of the fork which is flexing BACK. The distance the cable spans is increasing, effectively making the cable shorter, which is going to tighten the front brake, the same way tightening your grip would have. This makes the force at the fork greater, flexing it more, tightening the brake more, and so on. So far so good. Except that you'd have to be flexing the fork between the brake pad contact point and the brake cable hanger on the top of the headset; this also requires flexing the steerer and possibly the head tube. That's not impossible, I suppose. I have read that steerers can flex in the lower part, near the lower headset race. Maybe that can flex enough. Or maybe there's enough flex in the fork legs between the braze-on and the bottom headset cups; you'd only need a little bit of stretch, maybe a mm or so, to significantly tighten the brake. The alternative is the fork legs twisting as the brake pads are dragged forward. Oval tubing is poorly resistant to being twisted (which is why ovalized down tubes don't stiffen the BB- they are twisted rather than loaded laterally. And why Ritchey ovalizes the seat tube, which is loaded laterally). My thought is that the pads are dragged forward until the front edge lifts enough that friction is reduced and the rim can slip; as the pads snap back they grab again and the cycle is repeated. This is why a brake booster works, it prevents the fork legs from being twisted by constraining the ends of the braze-ons from swinging away from the centerline. Even simpler is if there's a bump at the rim joint or a bump in the rim from an impact; that can cause this sort of thing. The visible process is the wagging of the forks as a symptom of the stick-slip cycle. It can be very dramatic- my friend Steve's S-works looked like the front end was going to fly apart. This is a positive feedback that only stops when something lets go, and on the road, the thing that lets go is the road/tire interface. The tire momentarily lets go of the road, and the fork springs back forward which loosens the brake. When the tire hits the ground again it starts up all over again. Here's where we run into problems with this explanation IMHO. Since you're decelerating, you're loading the front tire more heavily and pushing it against the ground. This makes it harder for the tire to skip.
[RBW] Re: Tapping Bleriot brake bridge
Justin, I'm running vo 52 zepplin fenders on my bleriot with sheldon fender nuts. I tried to attach them with the daruma. but when it pulled the fender up flush to the bottom of the fork, the angle of the fork caused the front of the fender to dig into the tire. I needed to use the sheldon fender nut and bend the L bracket accordingly to get a good fender line. Erik -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: AR front brake shudder and fork flex
I guess what I struggle with is that I didn't change the cable, or hanger, or ferrule, or the fork...only the brakes themselves; and the problem stopped...completely...even with the same brake pads. One way to reduce braking performance with the same force is to change the contact area between the brake pad and the rim. Which is what happens when the pads go into a toe-out situation. And why would my front tire lift off the ground? In free body diaphragm terms, the braking force (and the fork flexing backwards) would increase the vertical load on the front tire contact patch. Angus On Feb 19, 4:04 pm, William tapebu...@gmail.com wrote: Tim If you think about it some more, I think you'll see it. The tire lifting off the ground un-flexes the fork, relaxing the cable tension and loosens the clamping force of the brakes on the rim. It can't be otherwise. Like a bow-and-arrow in reverse I'll go ahead and make a statement and claim it as fact and see if anyone can even anecdotally dispute it. We'll see where that takes us. Virtually everyone has seen, experienced or heard about this violent fore-aft shuddering on a bicycle under hard front braking. My claim is that every single one of them was a bike with cantilever brakes or center pull brakes. It doesn't happen with V brakes and it doesnt happen with caliper brakes, or disk brakes for that matter. That's because brakes with all-housing are immune to any flex-induced tensioning and detensioning of the cable. Canti-bikes and centerpull bikes don't HAVE to have this problem, but V-brake, disk brake, and caliper brake bikes can't have it. If this had to do with toed in brake pads micro gripping and releasing, it would be equally common on all rim brake types. Furthermore, there is no free-body diagram one could draw to claim that a brake caliper of any kind squeezing harder on a rim will result in the brake pad squeezing LESS hard on the rim and allow it to release. That's just not physically possible. The sliding rim sort of shrugging the brakepad off of it, like some little wrestling move doesn't hold up. On Feb 19, 1:33 pm, Tim McNamara tim...@bitstream.net wrote: On Feb 19, 2011, at 12:51 PM, Ray Shine wrote: Excellent explanation. Even I could make sense of it! Thank you! From: William tapebu...@gmail.com To: RBW Owners Bunch rbw-owners-bunch@googlegroups.com Sent: Sat, February 19, 2011 9:36:14 AM Subject: [RBW] Re: AR front brake shudder and fork flex This topic comes up repeatedly. The discussions typically focus on treatment, which is natural, because you just want the thing to go away. But understanding the cause is usually helpful in figuring out the treatment. The cause is as follows: You grab your front brake, which tries to stop the wheel rotating. The road is pushing back on your tire and your body's forward momentum is pushing forward on the front hub. This moment tries to bend back the front fork. You can do this part for yourself in the garage. Lock up the front brake and push forward on the bike. Everyone with me? Cool. Now look at the cable. The length of cable going from the hanger down to the brake is hanging in space in FRONT of the fork which is flexing BACK. The distance the cable spans is increasing, effectively making the cable shorter, which is going to tighten the front brake, the same way tightening your grip would have. This makes the force at the fork greater, flexing it more, tightening the brake more, and so on. So far so good. Except that you'd have to be flexing the fork between the brake pad contact point and the brake cable hanger on the top of the headset; this also requires flexing the steerer and possibly the head tube. That's not impossible, I suppose. I have read that steerers can flex in the lower part, near the lower headset race. Maybe that can flex enough. Or maybe there's enough flex in the fork legs between the braze-on and the bottom headset cups; you'd only need a little bit of stretch, maybe a mm or so, to significantly tighten the brake. The alternative is the fork legs twisting as the brake pads are dragged forward. Oval tubing is poorly resistant to being twisted (which is why ovalized down tubes don't stiffen the BB- they are twisted rather than loaded laterally. And why Ritchey ovalizes the seat tube, which is loaded laterally). My thought is that the pads are dragged forward until the front edge lifts enough that friction is reduced and the rim can slip; as the pads snap back they grab again and the cycle is repeated. This is why a brake booster works, it prevents the fork legs from being twisted by constraining the ends of the braze-ons from swinging away from the centerline. Even simpler is if there's a bump at the rim joint or a bump in the rim from an impact; that can cause this sort of thing. The
[RBW] Re: Stem Mounted Shifters?
Stem mounted shifters are increasingly appealing to me...in a few years it may cause me to act. Angus On Feb 17, 10:28 am, jsk jeff...@lightsideps.com wrote: Hi all, Just wondering if anyone knows of a manufacturer making modern, well built stem mounted shifters anymore (or ever)? You know, like the type that used come standard on Schwinn Collegiate bikes and the like? I mean, considering the devotion to upright bars here ... -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: What's diff between Sackville olive and grey-grid fabrics?
My understanding is that the olive is all cotton and the grid-grey is a polyester/cotton blend, ratio unknown. Personally, I'd expect the poly/cotton blend to be a little more durable but greatly prefer the olive. And we're talking in terms several years of daily use versus several years plus a few more of daily use. That is, I think both are quite durable. I've had my olive SaddleSack medium out in the rain for over an hour on several occasions amongst its hundred-plus days used; it looks broken in... weathered even... but not worn. I too am a bag-matcher. There is no shame in this. Yours, Thomas Lynn Skean On Feb 19, 1:08 pm, SFF jgre...@earthlink.net wrote: Hey Forrest - I have an XS Saddlesack in olive and a ton of others in grid-grey (TourSack, ShopSack and on and on...). The olive material seems to be slightly thicker and stiffer - sort of a brushed cotton canvas type of material. The grey ones seem to be a little thinner and more flexible. They have a slicker feel to them as well and clean a little easier. I even washed my ShopSack in the washing machine once and it came out real soft and a little faded, looks and feels real good. But then what do I know - I'm a bag matcher. I like the look of the grid-grey more than the olive. Also, to Grant's post yesterday about the GrabSack being an unexpected poor seller: From the first day I got mine, I told everyone that this is the best bag in the world. By far my favorite bag of all time. So, again, what do I know. Heading out the door for S24O #2 of the year (goal for this year is 10) on the Atlantis!!! Going to scare the wildlife a bit and hope they don't scare back. Joel (When I grow up, I want to be just like me.) On Feb 19, 10:23 am, Forrest ftme...@me.com wrote: Have searched for answer on RBW site without luck (but I'm not a real good searcher), and I'm not quite ready to call and bug someone there. Would rather bug all of you first! Sorry, and thanks. -- Forrest (in tropical Iowa City) -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: AR front brake shudder and fork flex
Angus It doesn't surprise me a whole lot. I've run the geometry numbers, and straddle height makes essentially no difference on mafac shape cantilevers. The feel at the lever is almost independent of straddle height. Low profile cantilevers depend a TON on straddle height. You can set up the brakes with a really low straddle for power and a squishy feel at the lever, or set it up tall for pukka pukka at the lever with much less power. With a tall straddle set up, its really really to load up the front brake. Like try to do an endo, you probably can't do it. That means you've de-powered your brakes so you can't get the feedback started. Just a guess. I experienced that on my cross bike. Neo-retros were terrifying. Touring cantis were a little better, and ceramic rims/pads were another step better. I think your observations are consistent. On Feb 19, 2:37 pm, Angus angusle...@sbcglobal.net wrote: I guess what I struggle with is that I didn't change the cable, or hanger, or ferrule, or the fork...only the brakes themselves; and the problem stopped...completely...even with the same brake pads. One way to reduce braking performance with the same force is to change the contact area between the brake pad and the rim. Which is what happens when the pads go into a toe-out situation. And why would my front tire lift off the ground? In free body diaphragm terms, the braking force (and the fork flexing backwards) would increase the vertical load on the front tire contact patch. Angus On Feb 19, 4:04 pm, William tapebu...@gmail.com wrote: Tim If you think about it some more, I think you'll see it. The tire lifting off the ground un-flexes the fork, relaxing the cable tension and loosens the clamping force of the brakes on the rim. It can't be otherwise. Like a bow-and-arrow in reverse I'll go ahead and make a statement and claim it as fact and see if anyone can even anecdotally dispute it. We'll see where that takes us. Virtually everyone has seen, experienced or heard about this violent fore-aft shuddering on a bicycle under hard front braking. My claim is that every single one of them was a bike with cantilever brakes or center pull brakes. It doesn't happen with V brakes and it doesnt happen with caliper brakes, or disk brakes for that matter. That's because brakes with all-housing are immune to any flex-induced tensioning and detensioning of the cable. Canti-bikes and centerpull bikes don't HAVE to have this problem, but V-brake, disk brake, and caliper brake bikes can't have it. If this had to do with toed in brake pads micro gripping and releasing, it would be equally common on all rim brake types. Furthermore, there is no free-body diagram one could draw to claim that a brake caliper of any kind squeezing harder on a rim will result in the brake pad squeezing LESS hard on the rim and allow it to release. That's just not physically possible. The sliding rim sort of shrugging the brakepad off of it, like some little wrestling move doesn't hold up. On Feb 19, 1:33 pm, Tim McNamara tim...@bitstream.net wrote: On Feb 19, 2011, at 12:51 PM, Ray Shine wrote: Excellent explanation. Even I could make sense of it! Thank you! From: William tapebu...@gmail.com To: RBW Owners Bunch rbw-owners-bunch@googlegroups.com Sent: Sat, February 19, 2011 9:36:14 AM Subject: [RBW] Re: AR front brake shudder and fork flex This topic comes up repeatedly. The discussions typically focus on treatment, which is natural, because you just want the thing to go away. But understanding the cause is usually helpful in figuring out the treatment. The cause is as follows: You grab your front brake, which tries to stop the wheel rotating. The road is pushing back on your tire and your body's forward momentum is pushing forward on the front hub. This moment tries to bend back the front fork. You can do this part for yourself in the garage. Lock up the front brake and push forward on the bike. Everyone with me? Cool. Now look at the cable. The length of cable going from the hanger down to the brake is hanging in space in FRONT of the fork which is flexing BACK. The distance the cable spans is increasing, effectively making the cable shorter, which is going to tighten the front brake, the same way tightening your grip would have. This makes the force at the fork greater, flexing it more, tightening the brake more, and so on. So far so good. Except that you'd have to be flexing the fork between the brake pad contact point and the brake cable hanger on the top of the headset; this also requires flexing the steerer and possibly the head tube. That's not impossible, I suppose. I have read that steerers can flex in the lower part, near the lower headset race. Maybe that can flex enough. Or maybe there's enough flex in the fork
[RBW] Re: AR front brake shudder and fork flex
I could never understand why you would put the stronger brake ( neo- retro) on the front. I know the rear installation sometimes has clearance problems but that is where you need the greater braking force closer to the center of gravity of bike/rider. Couple that with fork flex and the other associated issues and it's a no brainier to use the Touring version up front. Plus it adds some nice symmetry to the bike :^P ~Mike On Feb 19, 4:03 pm, William tapebu...@gmail.com wrote: Angus It doesn't surprise me a whole lot. I've run the geometry numbers, and straddle height makes essentially no difference on mafac shape cantilevers. The feel at the lever is almost independent of straddle height. Low profile cantilevers depend a TON on straddle height. You can set up the brakes with a really low straddle for power and a squishy feel at the lever, or set it up tall for pukka pukka at the lever with much less power. With a tall straddle set up, its really really to load up the front brake. Like try to do an endo, you probably can't do it. That means you've de-powered your brakes so you can't get the feedback started. Just a guess. I experienced that on my cross bike. Neo-retros were terrifying. Touring cantis were a little better, and ceramic rims/pads were another step better. I think your observations are consistent. On Feb 19, 2:37 pm, Angus angusle...@sbcglobal.net wrote: I guess what I struggle with is that I didn't change the cable, or hanger, or ferrule, or the fork...only the brakes themselves; and the problem stopped...completely...even with the same brake pads. One way to reduce braking performance with the same force is to change the contact area between the brake pad and the rim. Which is what happens when the pads go into a toe-out situation. And why would my front tire lift off the ground? In free body diaphragm terms, the braking force (and the fork flexing backwards) would increase the vertical load on the front tire contact patch. Angus On Feb 19, 4:04 pm, William tapebu...@gmail.com wrote: Tim If you think about it some more, I think you'll see it. The tire lifting off the ground un-flexes the fork, relaxing the cable tension and loosens the clamping force of the brakes on the rim. It can't be otherwise. Like a bow-and-arrow in reverse I'll go ahead and make a statement and claim it as fact and see if anyone can even anecdotally dispute it. We'll see where that takes us. Virtually everyone has seen, experienced or heard about this violent fore-aft shuddering on a bicycle under hard front braking. My claim is that every single one of them was a bike with cantilever brakes or center pull brakes. It doesn't happen with V brakes and it doesnt happen with caliper brakes, or disk brakes for that matter. That's because brakes with all-housing are immune to any flex-induced tensioning and detensioning of the cable. Canti-bikes and centerpull bikes don't HAVE to have this problem, but V-brake, disk brake, and caliper brake bikes can't have it. If this had to do with toed in brake pads micro gripping and releasing, it would be equally common on all rim brake types. Furthermore, there is no free-body diagram one could draw to claim that a brake caliper of any kind squeezing harder on a rim will result in the brake pad squeezing LESS hard on the rim and allow it to release. That's just not physically possible. The sliding rim sort of shrugging the brakepad off of it, like some little wrestling move doesn't hold up. On Feb 19, 1:33 pm, Tim McNamara tim...@bitstream.net wrote: On Feb 19, 2011, at 12:51 PM, Ray Shine wrote: Excellent explanation. Even I could make sense of it! Thank you! From: William tapebu...@gmail.com To: RBW Owners Bunch rbw-owners-bunch@googlegroups.com Sent: Sat, February 19, 2011 9:36:14 AM Subject: [RBW] Re: AR front brake shudder and fork flex This topic comes up repeatedly. The discussions typically focus on treatment, which is natural, because you just want the thing to go away. But understanding the cause is usually helpful in figuring out the treatment. The cause is as follows: You grab your front brake, which tries to stop the wheel rotating. The road is pushing back on your tire and your body's forward momentum is pushing forward on the front hub. This moment tries to bend back the front fork. You can do this part for yourself in the garage. Lock up the front brake and push forward on the bike. Everyone with me? Cool. Now look at the cable. The length of cable going from the hanger down to the brake is hanging in space in FRONT of the fork which is flexing BACK. The distance the cable spans is increasing, effectively making the cable shorter, which is going to tighten the front brake, the same way tightening
[RBW] Re: Tapping Bleriot brake bridge
Picked up some Sheldon's Nuts today. And ordered my White Hetres. Pretty excited for them to come in. Hoping my current fenders will fit them - if not I'd like to stay true with Berthouds but may have to go VO. -Justin On Feb 19, 5:09 pm, Erik C erikdcarl...@gmail.com wrote: Justin, I'm running vo 52 zepplin fenders on my bleriot with sheldon fender nuts. I tried to attach them with the daruma. but when it pulled the fender up flush to the bottom of the fork, the angle of the fork caused the front of the fender to dig into the tire. I needed to use the sheldon fender nut and bend the L bracket accordingly to get a good fender line. Erik -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Stem Mounted Shifters?
Suntour made power-ratchet stem mount shifters. A little digging in parts bins will turn up a nice pair I'm sure. On Feb 19, 5:15 pm, Angus angusle...@sbcglobal.net wrote: Stem mounted shifters are increasingly appealing to me...in a few years it may cause me to act. Angus On Feb 17, 10:28 am, jsk jeff...@lightsideps.com wrote: Hi all, Just wondering if anyone knows of a manufacturer making modern, well built stem mounted shifters anymore (or ever)? You know, like the type that used come standard on Schwinn Collegiate bikes and the like? I mean, considering the devotion to upright bars here ... -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] FS: TA chainring bolts
Ref.25 which can be seen here: http://sheldonbrown.com/harris/french-cranks.html#bottom $20 shipped to your door, even if that door is in Hawaii. :-) -- Cheers, David Redlands, CA *...in terms of recreational cycling there are many riders who would probably benefit more from improving their taste than from improving their performance.* - RTMS -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Stem Mounted Shifters?
Yes, decisions such as this one require considerable contemplation, research, analysis, soul-searching, and, certainly not least, consultation. You can't just jump into these things. Who knows what would happen? :) Yours, Thomas Lynn Skean P.S. I thought I saw on the web some stem-mounted clamp that could be used to hold modern downtube shifters. I'll look around and post back if I find it again. Good thing there's no rush! On Feb 19, 5:15 pm, Angus angusle...@sbcglobal.net wrote: Stem mounted shifters are increasingly appealing to me...in a few years it may cause me to act. Angus On Feb 17, 10:28 am, jsk jeff...@lightsideps.com wrote: Hi all, Just wondering if anyone knows of a manufacturer making modern, well built stem mounted shifters anymore (or ever)? You know, like the type that used come standard on Schwinn Collegiate bikes and the like? I mean, considering the devotion to upright bars here ... -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: On shipping bike parts to our two finest states
In Chicago at least, UPS is the third choice as they do not have evening, weekend delivery options and their inconveniently located facility is open only during weekday business hours. FedEx Home Delivery offers both (at a cost, but still). USPS of course has a key to get into condo buildings even if there is no door person. For delivery with signature requirements, there is a post office facility for every zip code with Saturday hours. Sure, I can route UPS deliveries to work. But being a bike only commuter, there are limits to the size of package I can receive there. And frankly, I prefer not having to use company mail room personnel to receive my purchases. With on line shopping rapidly becoming the largest retail sector, I hope UPS catches up with working peoples' needs. On Feb 19, 12:20 pm, Peter Pesce petepe...@gmail.com wrote: Grant For us east-coasters, would it be possible to at least offer the option of USPS? It's not a matter of cost as much as speed, at least for me, though it seems like anything I order costs $15 to ship, regardless, and paying for express shipping us a deal-killer. The real killer us that UPS is seven full days from CA to CT. That means if I decide I want or need something on a weekend and order it online, it ships that Monday but I don't even receive it in time for the next weekend, as it arrives the Monday after the Monday it ships. USPS is usually about 3 days coast to coast for reasonable size things. Just a thought. I'd like to buy more from Riv but I'm an instant gratification kind of guy! Pete On Feb 18, 7:00 pm, grant grant...@gmail.com wrote: UPS charges us $8.08 for under-a-pound boxes to major metropolitan areas in California. If you live in a van down by the river, it costs (us) more. A typical box weight here is 5 pounds. To the midwest, it costs (us) about $11. Alaska and Hawaii cost more, for sure. I wish we could get around UPS, but the other companies (FedX, USPS) either charge more or don't have tracking. Plus, the shippers are now super close buddies with Barry, our UPS guy, and even if FEDX got cheaper, it would take quite the Venezuelan FedX account manageress to get Robert and Vaughn to voluntarily, willingly, switch from UPS. It's not impossible, but unlikely. Our flat rate of $8 is below our cost, but in my head I'm still a 13- year old ordering from L.L. Bean and paying nothing. Still, we may have to raise rates. The thing of it is, we don't sell anything ending in a 9, and that's what a dollar increase would be. Another dollar, and it's into the double-digits, which seems a lot higher. Eight is magic here, for now. G -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: What's diff between Sackville olive and grey-grid fabrics?
The green cotton is very thick and rugged, even thicker than the cotton duck used on Carradice bags if I am not mistaken. -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: FS: TA chainring bolts
Spoken for, thanks for the interest!!! On Sat, Feb 19, 2011 at 6:09 PM, cyclotourist cyclotour...@gmail.comwrote: Ref.25 which can be seen here: http://sheldonbrown.com/harris/french-cranks.html#bottom $20 shipped to your door, even if that door is in Hawaii. :-) -- Cheers, David Redlands, CA *...in terms of recreational cycling there are many riders who would probably benefit more from improving their taste than from improving their performance.* - RTMS -- Cheers, David Redlands, CA *...in terms of recreational cycling there are many riders who would probably benefit more from improving their taste than from improving their performance.* - RTMS -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] Re: What's diff between Sackville olive and grey-grid fabrics?
That's true. I have both Carradice bags and a Saddlesack. The Saddlesack fabric is definitely thicker. I'm already on record as saying the Saddlesack large is the cat's pajamas. I have one mounted on my go-everywhere bike, and, well, it goes everywhere. Notebooks and a sweater when I go to class, groceries when I need to pick up a few meals worth after a ride, a cake if I happen to need to transport a cake, rain clothes and a sweater when I climb up in the hills-- it's dandy. On Sat, Feb 19, 2011 at 7:55 PM, Ginz theg...@gmail.com wrote: The green cotton is very thick and rugged, even thicker than the cotton duck used on Carradice bags if I am not mistaken. -- -- Anne Paulson My hovercraft is full of eels -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Rainy Mt.Diablo
After missing the AID's training ride due to BART delays, Will and I decided that the snow at the top of Mt.Diablo was calling. We decided to do our own training ride to make snow men at the top. Climbing was typical. Hard. With a mixture of rain, snow, ice and hail. Getting to the ranger station our dreams of snowmen and our names written in the snow was shattered when the road was closed due to ice on the road. Also got to stop by the shop to pick up a few things, took pictures of a Simpleone with a VO saddle. Nice fancy day. Pictures proved that it happened: http://www.flickr.com/photos/mannyacosta/sets/72157625966021279/ -Manny Rain is fun, hail is interesting, thunder is scary. Acosta -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Stem Mounted Shifters?
Thomas: Please post if you find something. I checked my Arabesques the clamp is way bigger than the stem. It would need a thick shim to work I'd probably start with a couple of tire boots or something equally ugly. Whatever's on Jenny's Homer is clean looking fits the look of the bike. dougP On Feb 19, 6:27 pm, Thomas Lynn Skean thomaslynnsk...@comcast.net wrote: Yes, decisions such as this one require considerable contemplation, research, analysis, soul-searching, and, certainly not least, consultation. You can't just jump into these things. Who knows what would happen? :) Yours, Thomas Lynn Skean P.S. I thought I saw on the web some stem-mounted clamp that could be used to hold modern downtube shifters. I'll look around and post back if I find it again. Good thing there's no rush! On Feb 19, 5:15 pm, Angus angusle...@sbcglobal.net wrote: Stem mounted shifters are increasingly appealing to me...in a few years it may cause me to act. Angus On Feb 17, 10:28 am, jsk jeff...@lightsideps.com wrote: Hi all, Just wondering if anyone knows of a manufacturer making modern, well built stem mounted shifters anymore (or ever)? You know, like the type that used come standard on Schwinn Collegiate bikes and the like? I mean, considering the devotion to upright bars here ...- Hide quoted text - - Show quoted text - -- You received this message because you are subscribed to the Google Groups RBW Owners Bunch group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
