What Is an OAP?
Both OAP and OAD are used in modern belt drive systems, but they function differently. OAP provides one-way rotation only and allows the alternator to freewheel during deceleration.
What Is an OAD?
OAD includes both a one-way clutch and an internal torsion spring. This spring absorbs engine vibration and provides additional damping.
Key Differences
| Feature | OAP | OAD |
|---|---|---|
| One-way clutch | Yes | Yes |
| Torsional spring | No | Yes |
| Vibration damping | Moderate | High |
| Application | Standard engines | High torque engines |
Which One Should You Choose?
It depends on the OE specification. Always follow the original vehicle design. Replacing OAD with OAP may lead to vibration and premature failure.