Say you pro bike fitters are trying to fit a rider, MOP’er training to move up, and he is very long in the torso, 5 feet 9 inches with an inseam of 30.5 inches. Do you maintain, or attempt to maintain, the 78 degree seat tube angle? By doing so, will that place too much weight over the front wheel causing poorer handling? In talking to one bike fitter, his recommendation was to reduce the seat tube angle to 76 degrees and look for a slightly longish top tube. This methodology would seem to leave the rider higher up front and catching a bit more wind. Thoughts?
If you’re on a road bike, it’s not recommended to go too steep as that will really change the handling characteristics off the bike. I rode my Giant TCR at 75/76 with a neutral setback post and the seat forward and it worked well. I tried a forward seat post to get 78/79 and it felt unstable.
I ride 79/80 or so on my P2K and it feels stable due to the design of the bike. I’ve tried 75/76 on it but when doing so elevated the aero bars and shortenned their adjustment to compensate. You will be a bit higher, but some aero types claim it’s more important to get narrow than low.
You can ride either/or based upon personal preference.
I read an article (I think it was a link from Gordo’s forum) that said something along the lines of:
When fitting a tri bike, you start with the front end, i.e. elbows on the aerobars, and work back from there. The seat tube angle is the result of a well fit bike, not the start.
Using that logic, I would guess that a good fit for a long torso may result in a bit shallower of a ride, but shouldn’t result in ‘catching more wind.’