I am transitioning from my old POS trek 820. Im buying a sette shadow frame, as well as a new wheelset and BB7s. For the bb7s, I would like to get new levers. What I want to know is whether I can simply replace The levers, and keep my old shimano shifter (im keeping the whole drivetrain from the trek) or whether I would need to buy new shifters. essintially are the Fr-5 lever compatible with shimano shifters.