Careful with Ibike. Ibike may be a solution for time trialists. I know of at least 2 racers who use it on their TT bike. Ibike relies on a calibration of the coefficient of drag via a coast down test. So for TT riders who are in the same position on generally smooth roads by themselves on the course I think it may be good. For riding in various positions (tops, hoods and drops), in a pack, rough roads and etc, Ibike IMO is not accurate enough to justify the cost. It is still expensive and comparable to a wired power tap.