Originally Posted by
patrick112
I bought a 2014 Cannondale supersix some years back for a great price. I am 5'8 with a 31 inch inseam, the bike is a 54 cm. 54 cm in other bikes fit me fine, but the Supersix never felt quite right and caused lower back pain. I had a bike fit, and the mechanic put a 60mm stem on there with like a 15% pitch. But the handling has been effected.
So I am going to sell the bike and buy something new. If I go for a supersix 52 cm will I be alright? Or is it likely that the geometry doesn't work for me too?
The effective difference in top tube length is 1cm, which means that you could go to a 70mm stem. Not really an improvement considering the 52 size frame is going to place the bars 1.5cm lower.
This is not the bike for you, IF your current fit is correct for you. If so, your fit is like that of someone with a short torso. The best bike for you would be a small bike with a tall headtube. Like a 50 or 51cm with a headtube that is taller than your current 54's. That will give you a short reach without bending further. Something like a Cervelo.
That said, did you get a real fit, or did a mechanic swap some stuff until you thought it was okay? Sometimes sitting upright isn't the right way of dealing with discomfort on the bike.