Jim, I have virtually the same road bike and cross bike (both made by Kelly circa 1996), save BB height, cross bike is higher due to the tires and geometry. I have done a ton of road riding on the cross bike as it was my commuter for years as well as my crossrace bike. Road bike 73 degree parallel, 58cm tt 58cm seat tube, 12cm stem. Cross bike, 73 degree parallel, 57cm tt and st. 12 cm stem. The bar tops are about the same drop from the saddle. I believe the road has an bb height of just under 11 inches with 25mm tires, the cross bike is something like just over 11.5" with 35mm tires, I will measure if people are interested. I recall the difference was greater than the tire size... My thoughts are that the cross bike very obviously heels over slower on high speed descents. I think it handles great otherwise. I have done a fair bit of mixed terrain riding on the road bike, including some cross racing (road bike clears 35mm tires as well). But other than tire size differences affecting the terrain I can ride on the road bike (shod 25mm) I really only noticed it on one high speed off camber turn in the berkeley hills. I dig the higher bb clearance due to using the cross bike as my mtb for 3 years, until I got a real one.
I did have a track bike with higher bb still than the cross bike, I loved how it handled, but it was almost 74 parallel with 56cm square tubes and usually had a pretty long stem on it, so too many variables.... Just some thoughts Tarik On Tue, Nov 3, 2009 at 5:49 PM, Jim Thill - Hiawatha Cyclery <thill....@gmail.com> wrote: > > I recall GP writing an article in one of the Readers a few years back > about comparing BB height with the heights of the foot pegs on stilts. > ISTR the conclusion was that the bikes with higher BBs tend to "feel" > more stable, but the trade-off is reduced precision in the control of > where the wheels actually go while riding. With the RBW-preferred low > BBs, it may feel a little wobbly (until one gets accustomed), but the > benefit is that one can control the pathline of the tire more > precisely. > > I was doing some low-difficulty offroading this morning on the 2009 > version of my winter fixie, which started life as a 1992 Trek 750 > Multi-Track. > http://www.flickr.com/photos/twowheelflight/3994127395/ > I don't have exact BB drop numbers, but a quick measurement reveals > the old Trek has its BB center about 12" off the floor, while my > Atlantis with the same tires has the BB about 10.5" off the floor. > Obviously the high BB makes for good fixed-gear cornering and improved > clearances for hopping over obstacles. I took these benefits as a > given, and understood that I must be giving up some desirable > characteristics of low BBs. > > The thing is, I think this high BB bike rides GREAT! I have no trouble > riding with enough precision to dodge sharp rocks and sticks in the > trail. It is one of the easier no-handed bikes I've ridden, too. My > Atlantis is probably my most ridden bike in the past 5 years, but I'm > not sure I yet understand the appeal of the low BB. Is it more > important when the bike is loaded, or when careening down some twisty > hill at 40+ mph? Or maybe I've just gotten accustomed to something > that is sub-optimal, and if I get back on the Atlantis tomorrow I'll > instantly understand the difference? (yes, I understand that BB height > isn't the only difference between the two bikes) > > Any thoughts? > > > -- Tarik Saleh tas at tariksaleh dot com in los alamos, po box 208, 87544 http://tariksaleh.com all sorts of bikes blog: http://tsaleh.blogspot.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 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 -~----------~----~----~----~------~----~------~--~---
