pretty much everybody using UT came from squared tapper BBs hehehe It can't be any other way unless your 1st bike has with Outter board cups. I have to agree with everybody, simple, it works, and u can feel some difference in the pedaling big time. BBs cups are cheap and easy to replace. Change cranks now is easy and fast, 1 small screwdriver to take the clip out, a 10 mm allen tool, pull the cranks out, done. 2 minutes tops.