To parent hands to something, turn IK on for the arms. The hands can now be parented and moved by moving the object they are parented to. If IK is on for the legs, then you should be able to parent the feet to the pedals/crank so that they follow the crank rotation. As an aside, Jim Burton has a race type bicycle at DAZ (Premier section) set up so you conform the people to the bike, and the fett follow the pedals.