Alternator Pulleys

Engines use pulley systems for transferring power from the crankshaft to various accessories via the belt. As their name implies, alternator pulleys are intended for transferring engine torque to the alternator. Older vehicles use solid pulleys designed to drive the alternator only. Most modern automobiles use one belt to drive all accessories, as opposed to the older system with three separate belts. With the increasing amount of power-operated amenities like heated seats, GPS navigators, audio systems, and more, the load on the alternator also increased. The modern automotive industry uses larger alternators and more powerful and efficient engines, which required changes in the serpentine drive system. Solid pulleys that used to be the standard for many years were replaced with overrunning alternator pulleys (OAPs) and overrunning alternator decouplers (OADs).

OAPs utilize an internal one-way clutch system that allows them to rotate freely in one direction and lock in the other one. Thanks to this mechanism, the alternator rotor coasts to a stop when the engine is shut down or decelerates quickly (during transmission shifting). Along with a one-way clutch, OADs utilize springs that absorb vibrations coming from the engine. This makes the pulley spin freely in one direction and have a distinctive “spring feel” when you try to rotate it in the opposite one. When choosing a replacement alternator pulley, keep in mind that these components are application specific and are not interchangeable, so the same type that your vehicle came with should be installed. We carry a complete selection of pulleys, so whether you need alternator decoupler pulleys or solid pulleys, we have you covered.