The present invention is a fully functioning two-wheel drive bicycle and embodiments thereof. The drive train which supplies power to the front wheel is incorporated into a modified frame and comprises a rear wheel driven by the traditional chain or shaft mechanism and the front wheel driven by a series of rigid shafts or other internalized drive systems. The front wheel drive is adaptable to all bicycle frame geometries including the double diamond mountain bike and road bicycle frame, touring, commuter and comfort bicycles, BMX, trials bicycles, and recumbent and tandem bicycles. The drive train lengthens and shortens in parallel with the shock-absorbing front fork and rear suspension. An engagement clutch, a one-way hub, and torque limiting clutch are also disclosed.