As the owner of a used bmc 55cm st x 56cm tt, I got the new derailleur setup and on the ride back from the bike shop I hit a rock and flat then a super long walk back to the bus stop because I carry nothing. Is this too small for me? Will I snap this seatpost at this height. lord help me. I kinda want to give it to my brother. I think he rides 53/54cm bikes and he doesn't ride at all. I installed a tube and realized I didn't know how to put a rear road wheel back on. I've only ridden fixed and shitty commuters that I never really flatted. Just sorta beat to shit and never dealt with again.