With the double saddle position seatposts (Cervelo P3C, P2C) if the rider rides very steep how do you start the fitting? Do you fit for a the steep position only?
With the P3, I feel perfectly if the saddle is forward but the frame is too big for the rear position.
Should I go one size smaller and change the stem?
Current setup is 56 cm with 90mm stem on the P3 forward position.
Alternative is 54 cm with 120mm stem
I had a P2K that fit very well in the steep position with a 90cm stem but in the slack position the effective top tube was too long unless I went with a abnormal short stem. I was never concerned however because I always rode the bike in the steep position. The only exception was when I entered a UIC legal TT where the seat had to be 5 cm behind the BB. The scrutineers made me change my normal riding position for this event. Consequently I raced that event stretched out in an uncomfortable position that I was unfamiliar with.
What are using the bike for? If only for triathlon then get set up in the steep position from the start if that’s how you prefer to ride. If you’re entering TT’s where the 5 cm rule applies then you may have to rethink.