I am looking at buying a frame and building a tri bike. I have some questions on what type of fit is more appropriate for triathlons. I love to race TT's as well, and consider the bike leg to be my strongest leg by far. I am looking at building a tri/tt bike, and I want to have a pretty aggressive position. My question is, is an aggressive position suitable for tri's, or will it wear you out too much and negate the idea of saving yourself for the run? I am sort of comparing the more typical tri bike position, where you are a little more upright, the stem comes up a bit higher, and the aero bars raise up at the end, to the more aggressive TT position where you are lower down, have less rise in the stem and head tube spacers, and tend to use flatter aero bars with little or no rise. I have a regular road bike to use for longer rides and all, this is basically a bike for races and tri/tt specific training rides. Assuming both types of positions are comfortable over the duration of the ride, are there any major differences on your body? As of right now, I am just doing sprints and getting ready to do some Olympic distances, but I would love to do a 1/2 IM or IM in the next few years.
Dan Empfield, inventor of the triathlon bike, often talks about how the best time trialists and top triathletes really have positions that are as close to each other as UCI rules will allow. It's his theory that if UCI rules didn't require 5cm of setback they would be even closer. I agree in a lot of ways.