I am using my road bike a Cervelo s2 with a dual position seat post and clip on bars. I have a couple questions about the time trail position. How far forward should I move the seat. On my road bike my kop is set a little back and on my current TT position it is a little forward. Is there a starting place as a rule of thumb? My second question is about the forearms should the be level,slightly tilted up or down ? And last is the stem on t bikes shorter or longer than a road bike? Thanks for any help
I could use any helpful suggestions. Thanks
Richard
I’m sure someone smarter than me will chime in. No simple answer to your questions. I highly recommend the bike fit articles on this web-site.
Moving the seat forward gives a steeper effective seat-angle. This allows you to lower the front while not closing your hip angle. At some point you may start to lose power. The right seat angle is an individual matter involving a balance of aerodynamics, power and comfort.
If “kop” refers to your knee over your pedal, I don’t think it really means much in a TT position.
Forearms have moved all over the place. When I started angled up was the norm, then level, then angled down, now the “mantis” position seems to have brought things full circle. I like mostly level. If you had access to a wind tunnel you could find what is optimum for you. I lack both cash and patience to use a wind-tunnel so I go with what feels best.
I don’t know if a stem is shorter on a TT bike, most TT bikes seem to have shorter top-tubes and I think riders use whatever bike/stem gets the best position. The distance from seat to arm-rests and handlebars is one of the most critical issues for my old back. So if your frame runs on the biggish side,shorter stem, smallish frame, longer stem. If you end up using a really short or really long stem, you are probably on the wrong sized bike.
Hopefully this helps. If you read all of Slowman’s articles, you may be qualified to tell me that I’m completely wrong.