[RBW] Re: Fenders and Speed
> I do keep thinking that in combination with a front fender extension like > Jan has talked about, a fitted back section of the front fender could direct > the air as it comes off the tire/rim so it flows behind the fender rather > than behind the tire. Somewhat like Zip's idea in integrating the shapes of > their aero tubular rim and their own tubular tire. The bigger issue is separating the tire tread from the oncoming air stream. The top of the tire is moving forward with twice your road speed. By putting a fender between tire and oncoming air, you reduce that speed by half. (Now the tire rotates at bike speed against the air inside the fender, and the oncoming air stream hits the fender at bike speed, too.) And since air resistance goes up by the square of the speed, you gain something. For this to work, the fender must extend beyond the top of the tire, otherwise, you probably gain little, or even act as a funnel directing more air onto the tire. Racing motorbikes all have fenders on the front wheel, not to keep the rider dry, but to improve aerodynamics. Regarding dimples (and I understand that Allan was tongue-in-cheek), I don't think you get boundary layer adhesion on bikes, as they vibrate too much. At least that is what recumbent builders have found with their fairings. (That is why dimples on rims probably offer no advantage on the road, even though they work great in the wind tunnel.) Jan Heine Editor Bicycle Quarterly http://www.vintagebicyclepress.com Follow our blog at http://janheine.wordpress.com/ -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] Re: Fenders and Speed
Fluted channels also add surface area, increasing the surface area of the boundary layer. So does a fin. In addition the fin could add torque to the fork/wheel/bar assembly in case of a crosswind. In case of a partial headwind (direction of wind velocity is not parallel to the direction of bike velocity), the laminar flow along the channels would be joined by some lateral flow across the channels. Would this component be turbulent? I dunno, but it's certainly not clear the channels or fins would do any good, at least not to me. I do keep thinking that in combination with a front fender extension like Jan has talked about, a fitted back section of the front fender could direct the air as it comes off the tire/rim so it flows behind the fender rather than behind the tire. Somewhat like Zip's idea in integrating the shapes of their aero tubular rim and their own tubular tire. On Wed, Nov 3, 2010 at 12:32 PM, Allan in Portland wrote: > No test to determine whether the hammered honjo, like dimples on a > golf ball, gives better aerodynamics than the smooth? :-) I've always > been partial to the fluted fenders. The flutes create laminar flow > channels at speeds above 32kph. > > And speaking of aerodynamics, am I alone in having considered adding a > small, vertically mounted wing to the front of my fender so as to add > some high-speed steering stability to a low-trail bike? > > -Allan > > -- > You received this message because you are subscribed to the Google Groups > "RBW Owners Bunch" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected] > . > For more options, visit this group at > http://groups.google.com/group/rbw-owners-bunch?hl=en. > > -- Ken Freeman Ann Arbor, MI USA -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Fenders and Speed
Allan - Yes, you are alone. Kevin On Nov 3, 9:32 am, Allan in Portland wrote: > No test to determine whether the hammered honjo, like dimples on a > golf ball, gives better aerodynamics than the smooth? :-) I've always > been partial to the fluted fenders. The flutes create laminar flow > channels at speeds above 32kph. > > And speaking of aerodynamics, am I alone in having considered adding a > small, vertically mounted wing to the front of my fender so as to add > some high-speed steering stability to a low-trail bike? > > -Allan -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Fenders and Speed
No test to determine whether the hammered honjo, like dimples on a golf ball, gives better aerodynamics than the smooth? :-) I've always been partial to the fluted fenders. The flutes create laminar flow channels at speeds above 32kph. And speaking of aerodynamics, am I alone in having considered adding a small, vertically mounted wing to the front of my fender so as to add some high-speed steering stability to a low-trail bike? -Allan -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Fenders and Speed
On Nov 3, 5:30 am, Ken Freeman wrote: > Jan, what was the fender shape that you tested? A smooth Honjo 43 mm fender. We made an extension for the front fender to test different lengths beyond the fork crown. We tested it with both 31 mm Grand Bois and 25 mm Vittoria tires. Jan Heine Editor Bicycle Quarterly 2116 Western Ave. Seattle WA 98121 http://www.vintagebicyclepress.com Follow our blog at http://janheine.wordpress.com/ -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] Re: Fenders and Speed
Jan, what was the fender shape that you tested? On Tue, Nov 2, 2010 at 9:24 PM, Jan Heine wrote: > We spent two days in the wind tunnel testing fenders, jackets, hand > position, lower handlebars, etc. The fenders made remarkably little > difference to aerodynamics. Of course, it probably depends on your > fenders, and if you have a front plastic fender that sticks up in the > air instead of following the curve of the tire, it may be different. > As Michael recalled, the ideal fender extends just forward of the fork > crown, and acts as a fairing for the tire. Everything else increases > drag. A full front fender still is better than nothing, as the fairing > effect outweighs the extra drag of the rear portion. Lowering you stem > by 20 mm had a great effect than most other changes, with the > exception of flapping jackets. Now that was a huge effect! Full > results are in Bicycle Quarterly Vol. 6, No. 1. (Commercial plug: Back > issues are available.) > > Jan Heine > Editor > Bicycle Quarterly > http://www.vintagebicyclepress.com > > Follow our blog at http://janheine.wordpress.com/ > > -- > You received this message because you are subscribed to the Google Groups > "RBW Owners Bunch" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected] > . > For more options, visit this group at > http://groups.google.com/group/rbw-owners-bunch?hl=en. > > -- Ken Freeman Ann Arbor, MI USA -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Fenders and Speed
We spent two days in the wind tunnel testing fenders, jackets, hand position, lower handlebars, etc. The fenders made remarkably little difference to aerodynamics. Of course, it probably depends on your fenders, and if you have a front plastic fender that sticks up in the air instead of following the curve of the tire, it may be different. As Michael recalled, the ideal fender extends just forward of the fork crown, and acts as a fairing for the tire. Everything else increases drag. A full front fender still is better than nothing, as the fairing effect outweighs the extra drag of the rear portion. Lowering you stem by 20 mm had a great effect than most other changes, with the exception of flapping jackets. Now that was a huge effect! Full results are in Bicycle Quarterly Vol. 6, No. 1. (Commercial plug: Back issues are available.) Jan Heine Editor Bicycle Quarterly http://www.vintagebicyclepress.com Follow our blog at http://janheine.wordpress.com/ -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Fenders and Speed
I get much more performance variability from the rider than from the fenders. Differences in tires I notice...fenders on or off I don't. Angus On Nov 1, 10:51 am, Eric Norris wrote: > Any thoughts from other riders with fendered bikes about whether they make > your bike slower? I've been riding my somewhat newly fendered Quickbeam > lately, and it seems to be a little more sluggish than I remember it being in > years past. > > --Eric N -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] Re: Fenders and Speed
A few lbs of weight is almost meaningless for the average rider, at least on flattish terrain. Wind and tire resistance is much more noticeable; wind especially when you ride in a windy area. As for fenders, I don't know if they are aero sluggards, but big, square Axiom Dutch-style grocery panniers are, for sure. On Mon, Nov 1, 2010 at 9:34 PM, Erik Powell wrote: > Don't get me started on the speed-killing effects of a rear rack, > panniers, and Col de la Vies. > > Erik > > On Nov 1, 7:15 pm, charlie wrote: >> I don't think my riding is slower when riding with fenders you could >> probably measure it and you would probably be infinitesimally slower. >> The benefits of having fenders would certainly outweigh any slight >> drop in speed I'm sure. I don't usually transport my bike and have >> never had the fenders get in the way when I do. You probably have a >> brake shoe rubbing or the wheel could be angled in the frame after >> installing the fenders, causing drag. Is your tire rubbing inside the >> fender ? If not, ignore the mild paranoia and ride through some mud >> puddles. Happy trails !!! = ) >> >> On Nov 1, 8:51 am, Eric Norris wrote: >> >> > Any thoughts from other riders with fendered bikes about whether they make >> > your bike slower? I've been riding my somewhat newly fendered Quickbeam >> > lately, and it seems to be a little more sluggish than I remember it being >> > in years past. >> >> > --Eric N >> >> > > -- > You received this message because you are subscribed to the Google Groups > "RBW Owners Bunch" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/rbw-owners-bunch?hl=en. > > -- Patrick Moore Albuquerque, NM For professional resumes, contact Patrick Moore, ACRW at [email protected] -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Fenders and Speed
Do you know of tests that indicate that it becomes a factor at 20 mph and above or is that your guess? The only fender aerodynamic tests I've ever read about are from Bicycle Quarterly. They were done at 22 mph and fenders had very little affect. Adding wider mudflaps at the bottom of the fenders did cause enough increase in drag to be measured. Until someone does wind tunnel tests at higher speeds we can only guess that there is a higher speed where fenders create enough additional drag that it can be noticed over increased drag of yourself and everything else on the bike. Given that, we could divide cyclists into two groups, those that spend the vast majority of their time at 22 mph and below (and when they are riding above 22 mph they are usually in a paceline) and those who do spend some portion of their solo riding time above 22 mph. For the first group there is no fender aerodynamic penalty and for the second group there may, or may not, be. About the best reasons I've found for not sporting fenders is if either you stuff your bike inside a car often or you live someplace where it never rains. On Nov 1, 11:34 pm, Erik Powell wrote: > If you're riding at ibob approved speeds (sub 15mph), fenders won't > make much of a difference. At 20mph and above, aerodynamics come into > play and fenders create an additional and perceptible drag. At 25mph > and above, you really start to feel it. > > Don't get me started on the speed-killing effects of a rear rack, > panniers, and Col de la Vies. > > Erik > > On Nov 1, 7:15 pm, charlie wrote: > > > > > I don't think my riding is slower when riding with fenders you could > > probably measure it and you would probably be infinitesimally slower. > > The benefits of having fenders would certainly outweigh any slight > > drop in speed I'm sure. I don't usually transport my bike and have > > never had the fenders get in the way when I do. You probably have a > > brake shoe rubbing or the wheel could be angled in the frame after > > installing the fenders, causing drag. Is your tire rubbing inside the > > fender ? If not, ignore the mild paranoia and ride through some mud > > puddles. Happy trails !!! = ) > > > On Nov 1, 8:51 am, Eric Norris wrote: > > > > Any thoughts from other riders with fendered bikes about whether they > > > make your bike slower? I've been riding my somewhat newly fendered > > > Quickbeam lately, and it seems to be a little more sluggish than I > > > remember it being in years past. > > > > --Eric N- 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 [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Fenders and Speed
If you're riding at ibob approved speeds (sub 15mph), fenders won't make much of a difference. At 20mph and above, aerodynamics come into play and fenders create an additional and perceptible drag. At 25mph and above, you really start to feel it. Don't get me started on the speed-killing effects of a rear rack, panniers, and Col de la Vies. Erik On Nov 1, 7:15 pm, charlie wrote: > I don't think my riding is slower when riding with fenders you could > probably measure it and you would probably be infinitesimally slower. > The benefits of having fenders would certainly outweigh any slight > drop in speed I'm sure. I don't usually transport my bike and have > never had the fenders get in the way when I do. You probably have a > brake shoe rubbing or the wheel could be angled in the frame after > installing the fenders, causing drag. Is your tire rubbing inside the > fender ? If not, ignore the mild paranoia and ride through some mud > puddles. Happy trails !!! = ) > > On Nov 1, 8:51 am, Eric Norris wrote: > > > Any thoughts from other riders with fendered bikes about whether they make > > your bike slower? I've been riding my somewhat newly fendered Quickbeam > > lately, and it seems to be a little more sluggish than I remember it being > > in years past. > > > --Eric N > > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Fenders and Speed
When it comes to speed, areodynamics is more important that weight. However on a more realiztic note I went through some of my numbers over the last few years before .. (brain washing) and now. So on a typical Hill Hundred ride in Indiana on my carbon fibre 17lb bike no bags fenders etc but riding with friends the average speed over the last few years has been around 15 to 16 mph. This year I road on my Tour Bike with fenders racks and a bag or two and started at just over 40lbs for the bike with heavy Marathon Plus tires.. average speed for the day taking it easy .. 14.6 Out of last years 4500 miles 3500 was on the "race bike" but social rides since I don't race.. average speed 15.4 Average speed on my fixie 16.2 Average on my tour bike on 350 mile DC to Pittsburg 10.4 mph. So from a 125lb bike loaded to a 17 pound race bike under normal (not racing) riding conditions had maybe a 5 to 6 mph average difference. Fenders to me would be so insignificant by themselves as to be laughable. I would imagine you could lower your handle bars 1/16 of an inch and make up for the added drag of the fenders. (I made that up as an example) So after all that brain stormin I sold my race bike .. Bought a Homer Hilsen..now you are stuck with my ramblings :) Have a great day Kelly On Nov 2, 5:38 am, Bruce wrote: > I put that off for two years, and finally took the honjos and racks off my > Saluki. The staining from salty sweat was pretty severe and to get good elbow > grease on them required removal. Two applications of Maguiar's Mag & Aluminum > Polish has helped, but not made them like new yet. In the meanwhile, riding > the > bike in a more CX looking mode has been kind of cool as a nice change up. > > ________________ > From: EricP > > Subject: [RBW] Re: Fenders and Speed > > What is this theory of riding without fenders? > Am just too lazy to take them off then put them on again. -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] Re: Fenders and Speed
Thanks Jan. I'll give 'em a good coat once they're clean again and stay with it. Our Summer weather in the south is conducive to lots of perspiration. From: Jan Heine If you want your fenders to resiststaining, put some car wax onto them before you install them, a -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Fenders and Speed
> I put that off for two years, and finally took the honjos and racks off my > Saluki. The staining from salty sweat was pretty severe and to get good elbow > grease on them required removal. Two applications of Maguiar's Mag & Aluminum > Polish has helped, but not made them like new yet. Aluminum is relatively porous. If you want your fenders to resist staining, put some car wax onto them before you install them, and about once a year afterward. Otherwise, you can get severe staining after just a few months of riding, even if you don't sweat on them. The volcanic ash of Mount St. Helens seems particularly corrosive... Jan Heine Editor Bicycle Quarterly http://www.vintagebicyclepress.com Follow our blog at http://janheine.wordpress.com/ -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
Re: [RBW] Re: Fenders and Speed
I put that off for two years, and finally took the honjos and racks off my Saluki. The staining from salty sweat was pretty severe and to get good elbow grease on them required removal. Two applications of Maguiar's Mag & Aluminum Polish has helped, but not made them like new yet. In the meanwhile, riding the bike in a more CX looking mode has been kind of cool as a nice change up. From: EricP Subject: [RBW] Re: Fenders and Speed What is this theory of riding without fenders? Am just too lazy to take them off then put them on again. -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Fenders and Speed
What is this theory of riding without fenders? Don't believe any of my bikes have been without since . . . well, dunno when. Am just too lazy to take them off then put them on again. Sorta wish was a fast enough rider that things like that made a difference. Eric Platt -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Fenders and Speed
I don't think my riding is slower when riding with fenders you could probably measure it and you would probably be infinitesimally slower. The benefits of having fenders would certainly outweigh any slight drop in speed I'm sure. I don't usually transport my bike and have never had the fenders get in the way when I do. You probably have a brake shoe rubbing or the wheel could be angled in the frame after installing the fenders, causing drag. Is your tire rubbing inside the fender ? If not, ignore the mild paranoia and ride through some mud puddles. Happy trails !!! = ) On Nov 1, 8:51 am, Eric Norris wrote: > Any thoughts from other riders with fendered bikes about whether they make > your bike slower? I've been riding my somewhat newly fendered Quickbeam > lately, and it seems to be a little more sluggish than I remember it being in > years past. > > --Eric N -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Fenders and Speed
I'm remembering a Bicycle Quarterly wind tunnel test which concluded that front fenders reduced drag slightly, and rear fenders increased drag slightly. Maybe it's the years not the fenders that are slowing us down? The only disadvantages I have found with fenders are that many bike racks do not easily accommodate them, complicating lock up, and neither do most car roof racks, requiring extra care in selecting among the more limited choices. Anyway, it's 30 degrees with a light wet snow falling in VT, so right now, I'm more concerned with slowing down when I hit the brakes than when I hit the pedals. Michael On Nov 1, 11:51 am, Eric Norris wrote: > Any thoughts from other riders with fendered bikes about whether they make > your bike slower? I've been riding my somewhat newly fendered Quickbeam > lately, and it seems to be a little more sluggish than I remember it being in > years past. > > --Eric N -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
[RBW] Re: Fenders and Speed
Funny you mention it. I just put fenders on my Sam yesterday and went for a ride. It felt slower, too. Though it might have been the 20 mph headwind On Nov 1, 11:51 am, Eric Norris wrote: > Any thoughts from other riders with fendered bikes about whether they make > your bike slower? I've been riding my somewhat newly fendered Quickbeam > lately, and it seems to be a little more sluggish than I remember it being in > years past. > > --Eric N -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
