Hello, ive just bought a new zhi zm1 mod frame and ive been riding it for a few of days and its been spot on, but lately my rear brake keeps popping, in the last 3 days its popped 3 times and every time its been when i do a sidehop. I run 175 tensiles and i think this may be the problem as when i pedal my feet are awfully close to the cylinders. If i got 160 length cranks would this solve the problem, i cant se this really giving me the clearance i need, im starting to get frustrated now s o can somebody help me. Thanks Dom