
An exercising bicycle is proposed, having a rear hub thereof being mounted with a spring seat, a coupling member, a spiral spring, a turning mechanism and a braking system. The spring seat is formed with a shaft for being sleeved with the coupling member. The spiral spring is placed between the coupling member and spring seat. The turning mechanism is operatably driven by body motion of a user, whereby the coupling member is urged to rotate with respect to the spring seat for twisting the spiral...











