A trike axle is a device used to create a three-wheeled motorcycle (trike). Commonly mounting to a sub-frame designed to fit the specific brand and model of motorcycle that is undergoing the trike conversion, the trike axle uses two axle bearings located on either side of the axle shaft where it connects to the frame. The trike axle also uses an open differential to drive the wheels forward. The axle can be either chain- or drive-shaft powered, with each type of drive system being equally used in the trike conversion and original model lineup. Made of two solid steel shafts with a tapered finish, the axle offers the strength required to create a safe and comfortable ride.
On the typical three-wheeled motorcycle, the rear axle is comprised of two solid steel axle shafts extending outward from an off-centered differential. The differential is commonly of the open type, with an occasional limited slip version offered on high-performance trikes. The open differential on the trike axle allows one tire to receive all of the motor's power while the other tire is in a free-wheeling mode. This allows the trike to drive around corners and turns in the road without attempting to push straight through the turn.
In a trike axle, one tire must be allowed to freewheel or the motorcycle would not be able to negotiate turns without dangerous pushing conditions. With both wheels receiving power from the engine, the trike would attempt to go straight even with the front tire turned completely to the side. This could actually result in the front tire sliding across the pavement as the trike attempts to turn. With a trike axle, the design is often very similar to that of a chain-operated riding lawn mower, where the power is applied to one side of the axle only.
In the high-performance trike axle, a limited slip differential is often used to send equal amounts of power to each rear tire. It also cuts power to one side when the trike enters a cornering situation. Spring clutches within the limited slip differential sense when one tire is attempting to turn faster than the other, as in a cornering situation. When this happens, the trike axle differential unlocks one side of the axle, allowing the tire to spin faster than the other side to comfortably negotiate the corner. In a straight line acceleration condition, the trike axle will apply power equally to both tires, thereby producing the utmost in traction.
