Re: [RBW] Re: Grant discounts the value of top tube length
On Tue, Aug 10, 2010 at 7:04 AM, Bob Cooper wrote: > The top tube should really be measured from a point in space that is > directly above the bottom bracket spindle to the center of the headset > lock nut and level with the lock nut. I think that's an important measurement to know, as is the opposite - the setback from that point to the top of the seat post, but those are really just pieces of the overall reach measurement. If i understand Grant's post correctly, his approach puts the priority on proper saddle position first, and the TT length is simply whatever it needs to be to get the bars within the range of adjustability that bars and stem will cover. If you know your preferred reach and bar height, the bars you want to use and desired stem length, the TT length is naturally derived from the earlier decisions. This is a custom frame drawing, of course, which is why deciding the TT length ahead of time is meaningless. When shopping for an already-built frame, it IS important to know your reach, and be able to take those frame measurements to decide if it will be within the range of reasonable seatpost and stem adjustability to get the fit you want. I think what Grant is saying is that the TT number can't be looked at in an isolated way when ST angle, HT angle and bar height also affect reach. -- Bill Connell St. Paul, MN -- 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: Grant discounts the value of top tube length
> Every woman I know has had a tremendously hard time fitting frames (whatever > the maker) due to "reach." They try to correct with super short stems, > Terry shorter reach bars, compact levers, etc. This is after they size down > a frame from what they could/should be riding based on PBH. For women, it > seems to definitely be a factor to consider. My read of the article is Grant says TT length itself is not so important as other factors including joint angles and other tube lengths. The Sweetpea in this photo, built by a woman for a woman, uses angles one does not normally see to get what I am pretty sure is a fine fitting bike for its obviously pleased owner. http://www.flickr.com/photos/lynnefitz/4867248171/in/set-72157623345581999/ My read of the article is this is exactly what GP is getting at. On Aug 9, 9:35 pm, cyclotourist wrote: > Every woman I know has had a tremendously hard time fitting frames (whatever > the maker) due to "reach." They try to correct with super short stems, > Terry shorter reach bars, compact levers, etc. This is after they size down > a frame from what they could/should be riding based on PBH. For women, it > seems to definitely be a factor to consider. > > > > > > On Mon, Aug 9, 2010 at 2:14 PM, William wrote: > > In the most recent step on the frame-drawing tutorial, Grant stated > > more directly than I can recall his feeling about top tube length: > > > "It's not the key, or even a key dimension. It matters, but not nearly > > as much as other things, or as much as people think it does. Bar > > height affects how far you have to reach to the bar more than top tube > > length does. Seat tube angle affects reach, too. But at some point > > yep, you gotta pick a top tube length." > > > On every bicycle forum on the planet, including this one, there will > > be numerous posters who emphatically state that top tube length is the > > single most important dimension on a bike, and that frame size itself > > should be stated as a top tube length dimension rather than a seat > > tube length dimension. I know I used to be convinced of that thinking > > and am only beginning to accept the possibility of an alternative. > > The fact is, everybody wants to know what the top tube length is, so > > Grant lists it. If handlebar height is way more important, then I > > wonder why Grant/Riv don't propose a way to quantify that > > characteristic on a frame or a bike. I can't think of an easy way to > > do it, either. Is it just the altitude of the headset locknut with a > > particular normal tire? Is it the x,y coordinates of the headset > > locknut relative to (0,0) placed at the center of the BB? > > > -- > > 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. > > -- > Cheers, > David > Redlands, CA > > "One man's religion is another man's belly laugh." > --Robert A. Heinlein- 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: Grant discounts the value of top tube length
The top tube should really be measured from a point in space that is directly above the bottom bracket spindle to the center of the headset lock nut and level with the lock nut. One way to grasp the concept embodied in the phrase “the top tube is not important” is to visualize, or simply look at, a bike without a top tube. Like this one: http://oldbike.wordpress.com/1928-raleigh-cross-frame-ladies/ Or like this one: http://www.flickr.com/photos/singlespeedmaniac/2731884171/ Or like this one: http://www.flickr.com/photos/littlepixel/2559892268/ Or to imagine a bike with an 75 degree seat tube angle and this seatpost: http://www.flickr.com/photos/7556...@n06/2180468983/in/photostream/ Or this one: http://www.rivbike.com/products/show/nitto-wayback-seat-post-272-x-250mm/11-048 Enjoy, Bob Cooper -- 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: Grant discounts the value of top tube length
eRitchie designs all frames for a 1000mm wheelbase? On Tue, Aug 10, 2010 at 12:14 AM, Fai Mao wrote: > Richard Sachs builds his bikes around the top tube length. However, he > assumes a 100 cm stem and a certain reach on the bar. That is why Sachs > frames have really odd frame angles with numbers like 72.454 The angles fit > around the top tube based upon a 1 meter wheelbase > > > On Tue, Aug 10, 2010 at 11:49 AM, andrew hill wrote: > >> it's a factor for me too - 84.5 pbh and 5'11 for me. >> >> not totally sure how to compensate.. i end up pushing the seat way back >> and putting the bars up high .. but i think that unweights the front end a >> bit too much, and contributes to wandering handling on my Sam Hillborne. >> >> -andrew >> >> On Aug 9, 2010, at 8:01 PM, kps wrote: >> >> > >> > >> > On Aug 9, 9:35 pm, cyclotourist wrote: >> >> Every woman I know has had a tremendously hard time fitting frames >> (whatever >> >> the maker) due to "reach." >> > >> > it's definitely a factor for me. i'm 5'8-1/2" or so, with a pbh of >> > 84.45 >> > >> > -- >> > 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. >> > >> >> -- >> 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. >> >> > > > -- > Fai Mao > The Blogger who sometimes responds to comments > > -- > 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.
Re: [RBW] Re: Grant discounts the value of top tube length
My view is that if you need to push your saddle so far back, do so, it's where your butt wants to be given the riding style. If you can't achieve that position with a normal or at least available seatppost, the seat tube angle needs to be numerically lower - a custom frame perhaps. After that your desired reach is based on your upper body riding position, and selecting it is much more art than science, thought you can use geometry once you know your desired body posiiton and dimensions. Other considerations include head tube angle and front wheel position, for desired steering and clearances (tight for racing or looser for a tourer or rando-type bike). Then you can set chainstay length to establish weight distribution. That's how you won't have a front wheel that's too light. BTW, have you weighed the bike wheel by wheel with you on board? Then you'll know how far the bike deviates from the "normal" 55% rear 45% front with you on it. Or if you can go through all this as an intellectual, non-frame building exercise, you might be able to find the frame parameters that fit your needs. Then you can just shop for a suitable existing frame. But there's another possibility: your positioning is not best for you when you slam that saddle, and a more basic adjustment and re-acclimation is needed. Yet a third, is to speak to Richard Sachs or another of the "greats," and see if you can pay for a custom frame design. Then shop your desired dimensions to a fabricator who is affordable and with better response time. On Mon, Aug 9, 2010 at 11:49 PM, andrew hill wrote: > it's a factor for me too - 84.5 pbh and 5'11 for me. > > not totally sure how to compensate.. i end up pushing the seat way back and > putting the bars up high .. but i think that unweights the front end a bit > too much, and contributes to wandering handling on my Sam Hillborne. > > -andrew > > On Aug 9, 2010, at 8:01 PM, kps wrote: > > > > > > > On Aug 9, 9:35 pm, cyclotourist wrote: > >> Every woman I know has had a tremendously hard time fitting frames > (whatever > >> the maker) due to "reach." > > > > it's definitely a factor for me. i'm 5'8-1/2" or so, with a pbh of > > 84.45 > > > > -- > > 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. > > > > -- > 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: Grant discounts the value of top tube length
Wow! I have a 86.4 PBH and am also 5' 11" with a short reach (short arms) My current bike (Surly Trucker) is similar to the Atlantis and has a fairly long top tube for a 58cm frame and I switched to a 75mm stem and viola the fit is now perfect for me given the top tube length. I shove my B17 all the way back in my Nitto two bolt post and my bars are a little above saddle height. I had used a 90 mm stem but never could get comfortable. This small change has made this bike worth keeping. I think your legs are shorter and you may benefit from moving the saddle forward 2 cm +/- and lowering your bar to level with the saddle. Maybe even getting a longer stem too. It sounds like you have a longer trunk and shorter legs than me although arm length can have a big effect too. Your maxed out setback and high bar will reduce weight on the front end and put more on your saddle. You need to experiment and find what works for your body. On Aug 9, 8:49 pm, andrew hill wrote: > it's a factor for me too - 84.5 pbh and 5'11 for me. > > not totally sure how to compensate.. i end up pushing the seat way back and > putting the bars up high .. but i think that unweights the front end a bit > too much, and contributes to wandering handling on my Sam Hillborne. > > -andrew > > On Aug 9, 2010, at 8:01 PM, kps wrote: > > > > > On Aug 9, 9:35 pm, cyclotourist wrote: > >> Every woman I know has had a tremendously hard time fitting frames > >> (whatever > >> the maker) due to "reach." > > > it's definitely a factor for me. i'm 5'8-1/2" or so, with a pbh of > > 84.45 > > > -- > > 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 > > athttp://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 [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: Grant discounts the value of top tube length
Richard Sachs builds his bikes around the top tube length. However, he assumes a 100 cm stem and a certain reach on the bar. That is why Sachs frames have really odd frame angles with numbers like 72.454 The angles fit around the top tube based upon a 1 meter wheelbase On Tue, Aug 10, 2010 at 11:49 AM, andrew hill wrote: > it's a factor for me too - 84.5 pbh and 5'11 for me. > > not totally sure how to compensate.. i end up pushing the seat way back and > putting the bars up high .. but i think that unweights the front end a bit > too much, and contributes to wandering handling on my Sam Hillborne. > > -andrew > > On Aug 9, 2010, at 8:01 PM, kps wrote: > > > > > > > On Aug 9, 9:35 pm, cyclotourist wrote: > >> Every woman I know has had a tremendously hard time fitting frames > (whatever > >> the maker) due to "reach." > > > > it's definitely a factor for me. i'm 5'8-1/2" or so, with a pbh of > > 84.45 > > > > -- > > 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. > > > > -- > 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. > > -- Fai Mao The Blogger who sometimes responds to comments -- 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: Grant discounts the value of top tube length
it's a factor for me too - 84.5 pbh and 5'11 for me. not totally sure how to compensate.. i end up pushing the seat way back and putting the bars up high .. but i think that unweights the front end a bit too much, and contributes to wandering handling on my Sam Hillborne. -andrew On Aug 9, 2010, at 8:01 PM, kps wrote: > > > On Aug 9, 9:35 pm, cyclotourist wrote: >> Every woman I know has had a tremendously hard time fitting frames (whatever >> the maker) due to "reach." > > it's definitely a factor for me. i'm 5'8-1/2" or so, with a pbh of > 84.45 > > -- > 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. > -- 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: Grant discounts the value of top tube length
Perhaps I'm reading this incorrectly but I think we're misreading Grant's comments on TT length. He is not saying that TT length is unimportant, only that it is a dependent variable. I think the understanding of "the TT is not important" should be restated as "the TT is a dependent variable", in that after one tries to tweak the important independent variables, and the TT will be whatever it will be. See http://www.rivbike.com/blogs/news_post/251 On Aug 9, 8:01 pm, kps wrote: > On Aug 9, 9:35 pm, cyclotourist wrote: > > > Every woman I know has had a tremendously hard time fitting frames (whatever > > the maker) due to "reach." > > it's definitely a factor for me. i'm 5'8-1/2" or so, with a pbh of > 84.45 -- 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: Grant discounts the value of top tube length
I had a nice discussion with Grant regarding the TT length as we narrowed down the details of a Riv on order. Basically, if I understood Grant correctly, his explanation was exact as Ken's is below. It all makes sense, really, since no one sits on the TT. Our contact points on the bike are the saddle, the handlebar and the pedals. Whatever's in between those three points can be extremely variable and not impact the three points as long as they cancel each other out; for example, a short TT and a steep ST angle cancelled out by a extreme setback seatpost with the saddle shoved back. -B On Aug 9, 7:14 pm, Ken Freeman wrote: > I don't think top tube length is anywhere near the most important measure of > a frame. Reach from the ischeal support points on the saddle to the points > of grip on the handlebars is important, as is the position of the ischeal > supports relative to the BB axis. The horizontal distance from the ischeal > supports to the BB, or to a vertical that intersects it, is a function of > seat tube angle, its length, seatpost setback, and saddle selection. The > remainder of reach (making the simplifying assumption of horizontal reach) > is from the BB intersecting vertical to the chosen handlebar grips, let's > say the hoods. That distance is made up of the remainder of the top tube, > the stem and it's extension, the handlebar curvature, and the design of the > brake lever or brifter. There's a lot more involved than the top tube. > > By making some assumptions about handlebar, brifter, and stem reaches one > may come up with a criterion for top tube length, but if you don't specify > the seat tube angle, seatpost setback, saddle design, and saddle > positioning, it is not possible to compare frames based on TT length. The > difference in this rear half of the reach among different frame arrangements > can be in the 4 cm range. How can one say "I need 53 cm, and 54 is too > long" if there could be a 4 cm difference in hand gripping position? > > -- > 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: Grant discounts the value of top tube length
On Aug 9, 9:35 pm, cyclotourist wrote: > Every woman I know has had a tremendously hard time fitting frames (whatever > the maker) due to "reach." it's definitely a factor for me. i'm 5'8-1/2" or so, with a pbh of 84.45 -- 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: Grant discounts the value of top tube length
I don't think top tube length is anywhere near the most important measure of a frame. Reach from the ischeal support points on the saddle to the points of grip on the handlebars is important, as is the position of the ischeal supports relative to the BB axis. The horizontal distance from the ischeal supports to the BB, or to a vertical that intersects it, is a function of seat tube angle, its length, seatpost setback, and saddle selection. The remainder of reach (making the simplifying assumption of horizontal reach) is from the BB intersecting vertical to the chosen handlebar grips, let's say the hoods. That distance is made up of the remainder of the top tube, the stem and it's extension, the handlebar curvature, and the design of the brake lever or brifter. There's a lot more involved than the top tube. By making some assumptions about handlebar, brifter, and stem reaches one may come up with a criterion for top tube length, but if you don't specify the seat tube angle, seatpost setback, saddle design, and saddle positioning, it is not possible to compare frames based on TT length. The difference in this rear half of the reach among different frame arrangements can be in the 4 cm range. How can one say "I need 53 cm, and 54 is too long" if there could be a 4 cm difference in hand gripping position? On Mon, Aug 9, 2010 at 8:48 PM, Lisa wrote: > I think the point is, that reach isn't the same as top tube length. > Reach, which for me is a key component of fit, does depend on top tube > length, but also on seat tube angle, handlebar height, etc. > > I have an old Peugeot and a new Atlantis that have exactly the same > effective top tube length. But the seat angle on the Peugeot is 76 > degrees (so I have to shove my saddle all the way back), and on the > Atlantis it's 72.5 degrees (and my saddle is centered on the seat > tube). In the end, my reach is quite a bit longer on the Peugeot. > > On Aug 9, 5:14 pm, William wrote: > > In the most recent step on the frame-drawing tutorial, Grant stated > > more directly than I can recall his feeling about top tube length: > > > > "It's not the key, or even a key dimension. It matters, but not nearly > > as much as other things, or as much as people think it does. Bar > > height affects how far you have to reach to the bar more than top tube > > length does. Seat tube angle affects reach, too. But at some point > > yep, you gotta pick a top tube length." > > > > On every bicycle forum on the planet, including this one, there will > > be numerous posters who emphatically state that top tube length is the > > single most important dimension on a bike, and that frame size itself > > should be stated as a top tube length dimension rather than a seat > > tube length dimension. I know I used to be convinced of that thinking > > and am only beginning to accept the possibility of an alternative. > > The fact is, everybody wants to know what the top tube length is, so > > Grant lists it. If handlebar height is way more important, then I > > wonder why Grant/Riv don't propose a way to quantify that > > characteristic on a frame or a bike. I can't think of an easy way to > > do it, either. Is it just the altitude of the headset locknut with a > > particular normal tire? Is it the x,y coordinates of the headset > > locknut relative to (0,0) placed at the center of the BB? > > -- > 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: Grant discounts the value of top tube length
I think the point is, that reach isn't the same as top tube length. Reach, which for me is a key component of fit, does depend on top tube length, but also on seat tube angle, handlebar height, etc. I have an old Peugeot and a new Atlantis that have exactly the same effective top tube length. But the seat angle on the Peugeot is 76 degrees (so I have to shove my saddle all the way back), and on the Atlantis it's 72.5 degrees (and my saddle is centered on the seat tube). In the end, my reach is quite a bit longer on the Peugeot. On Aug 9, 5:14 pm, William wrote: > In the most recent step on the frame-drawing tutorial, Grant stated > more directly than I can recall his feeling about top tube length: > > "It's not the key, or even a key dimension. It matters, but not nearly > as much as other things, or as much as people think it does. Bar > height affects how far you have to reach to the bar more than top tube > length does. Seat tube angle affects reach, too. But at some point > yep, you gotta pick a top tube length." > > On every bicycle forum on the planet, including this one, there will > be numerous posters who emphatically state that top tube length is the > single most important dimension on a bike, and that frame size itself > should be stated as a top tube length dimension rather than a seat > tube length dimension. I know I used to be convinced of that thinking > and am only beginning to accept the possibility of an alternative. > The fact is, everybody wants to know what the top tube length is, so > Grant lists it. If handlebar height is way more important, then I > wonder why Grant/Riv don't propose a way to quantify that > characteristic on a frame or a bike. I can't think of an easy way to > do it, either. Is it just the altitude of the headset locknut with a > particular normal tire? Is it the x,y coordinates of the headset > locknut relative to (0,0) placed at the center of the BB? -- 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: Grant discounts the value of top tube length
There is sort of a way of quantifying it, and it's apparently used by some professional fitters. When I was professionally sized at the Tommasini factory in Italy, they took a measurement that went from the center of the front hub to the center of the handlebar/stem clamp. It was ostensibly to tell me how high the stem/bars should be, given the other coordinates of the fit and frame that we worked out as I pedaled on the fit machine and he looked at my positioning. They also provided a very specific top tube length (54.5 cm) that was supposed work with the either of two seat tube angles that we were considering (73 and 73.5 degrees). On the other hand, and somewhat curiously, they did not bother to specify a head tube angle. My guess is that it would have been determined in the process of building the frame. Or perhaps it's proprietary information to Tommasini. I dunno. I didn't end up ordering a frame (yet). But they have my numbers on file for when I finally have the scratch to pull the trigger. Aaron On Aug 9, 2:14 pm, William wrote: > In the most recent step on the frame-drawing tutorial, Grant stated > more directly than I can recall his feeling about top tube length: > > "It's not the key, or even a key dimension. It matters, but not nearly > as much as other things, or as much as people think it does. Bar > height affects how far you have to reach to the bar more than top tube > length does. Seat tube angle affects reach, too. But at some point > yep, you gotta pick a top tube length." > > On every bicycle forum on the planet, including this one, there will > be numerous posters who emphatically state that top tube length is the > single most important dimension on a bike, and that frame size itself > should be stated as a top tube length dimension rather than a seat > tube length dimension. I know I used to be convinced of that thinking > and am only beginning to accept the possibility of an alternative. > The fact is, everybody wants to know what the top tube length is, so > Grant lists it. If handlebar height is way more important, then I > wonder why Grant/Riv don't propose a way to quantify that > characteristic on a frame or a bike. I can't think of an easy way to > do it, either. Is it just the altitude of the headset locknut with a > particular normal tire? Is it the x,y coordinates of the headset > locknut relative to (0,0) placed at the center of the BB? -- 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: Grant discounts the value of top tube length
TT length is one of those "it is , but it isn't" things. If you ride a bike with too short of a TT , it is. If not it isn't. That's why you get the polar opposite opinions. Being tall, and ridden many short TT'd frames ,it is important to myself because stems only reach so far. They never compensate for an overly short TT. I find a longer TT'd bike with a shorter stem always feels better to ride than a short TT bike with a long stem. Of course, the height of the head tube in relation to the BB is just as important. If you've ever had your knees hit your headset while climbing you know the importance of TT length. -- 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.
