It all depends on the BB shell height and if it is a converted road frame or a track frame; even here clearance can vary. I run 170's on my track bike and have never come close to striking a pedal. If you have a conversion w/ semi horizontal drop outs the further back in the dropouts you position the axel the lower the BB shell height will become. Obviously a track frame is not subject to this problem. All I can say is measure, measure, measure and then measure. I don't like to be limited by my ride so screw riding conservatively because of mechanical limitations. I would def. recommend 165 for a conversion and would never hesitate to run 170 on a track frame. MTC.