Originally Posted by
mikeread
I built an Audax frame a few years back and have been riding it ever since.
It is built with a Reynolds 631 main triangle (all .8 .5 .8) 28.6 TT and ST 31.2 DT and 31.7 HT with 725 seat stays and Columbus chain stays (cannot remember the specs of these) My weight is 168lbs and I am 6 foot tall
The bike is supremely comfortable and perfect for winter rides, Audax rides etc. It is a little flexy however and not ideal for fast club rides. I did take it touring once with just rear paniers and fast down hills were interesting
I am now planning to build another frame, again with 631 (or possibly 853) but want to make a pure road bike for faster club rides. So I would like it to be less flexy to improve handling whilst sacrificing as little comfort as possible. and of course, not adding too much weight.
My initial thoughts are below, your comments, advice and criticism would be appreciated.
<<sorry, snipped a lot of good stuff ...>>
Does this all seem logical and practical ?
I'm not a designer or builder, so I have less to contribute than the others in the thread, to critique your work. But I want a frame I would call "Audax" and that is very comfortable to my ol' body. I have a first O/S frame in ELOS, and it is a great and comfortable ride (a Mondonico ELOS). But I also have a few standard diameter frames in conventional Columbus SL and Reynolds 531 DB, and I know the physics of tube flexibility. I'm using similar wheels and tires on all of these (28 mm clinchers on Mavic Open Pro, or 22 mm tubular on Mavic GP4, no fatties on these bikes), and am surprised that the oversize tubings do so well in comfort and (seemingly) suppleness. Why aren't the 531 and SL frames more comfortable than the ELOS frame with 28 mm TT and ST, and 31 mm DT? I haven't tried to evaluate them mathematically in terms of belly moment of inertia, but I don't think I could deal well with the full butting profile anyway.
I also wonder if the step to stiffer tubes for the Go-fast significantly improves speed in a group-ride scenario, and why?
Also Mike, what wheels and tires are you using on the Audax, and what do you plan to use on the Go-fast?
Finally, it strikes me 75 mm trail for a fast road bike is a LOT of trail, though I've seen it quoted on hybrid-style frames. My nice Eyetalians are all around 60 mm trail.