Many vintage formula cars and sports racers use these rubber drive donuts in the drive axles. Donut couplings allow significant angular deflection (up to 5 degrees constant or 10 degrees momentary) without requiring any lubrication. Rubber construction also absorbs shock loading and vibration. The rubber should be inspected for cracks after each season or after any off-track excursion.
This Standard capacity size was standard equipment on many Formula Ford, Formula Junior, and D Sports Racers. The 3.78" bolt circle was commonly used with the Hewland Mk-Series gearbox.
| Standard Duty Rubber Donut Drive Axle Coupling |
|---|
| Type | Application | Construction | Torque
Capacity
(each)* | Bolt Circle
assembled | Overall Diameter
assembled | Bolt
Diameter | Width
at bolt holes |
|---|
| Standard | FJ, FF, DSR,
Hillman Imp | Rubber | 140 lb-ft | 3.78" | 5.38" | 7/16" | 1.83" |
* Some cars use these donuts as driveshaft joints, in which case the engine torque must not exceed the stated capacity. When used as drive axle joints, each axle theoretically handles half of the engine torque. In those applications, the engine torque must be less than 2 times the stated capacity.
Save your suspension! We now offer Axle Savers, a bolt-on Centering Kit for Rubber Drive Donuts. This easy bolt-on kit can save your rear suspension in case of a drive donut failure.
