ARP Wheel Stud Knurl Fit

Wheel Stud Hole Sizes and Proper Interference Fit for the Knurl

Our OEM replacement wheel studs are designed to press-fit into the original hole in the OEM hub (preferably with a hydraulic press, as using a nut can create problems).

If you are using one of our kits in another application, the hole should be checked to ensure it falls within the correct tolerance to allow for the proper amount of interference, so that the stud won’t spin in the hole. For steel and cast iron hubs, the hole should be 0.006-0.016˝ smaller than the Knurl Diameter. For aluminum hubs, the hole should be 0.010-0.016˝ smaller than the Knurl Diameter. As a courtesy, we have provided the closest standard drill size that will provide a hole in that range.

If the hole is larger than the tolerance listed for the material, then the studs should not be used with that hub. The interfernce fit will not be tight enough and the stud could spin in the hole.

If you need to drill out the holes in your hub, the holes must be kept perpendicular to the face of the hub. If you do not have a fixture that clamps to the hub to guide the drill straight, use a setup similar to the one in the image at below. (A hand drill will not produce satisfactory results.)

All ARP wheel studs have an underhead radius. Each hole must be chamfered 0.025˝ to clear the underhead radius and prevent stud failure.