Wheel Studs

Wheel studs stay fixed in the hub, and the wheel is held on by nuts rather than bolts. This category holds press-in stud kits listed by thread and under-head length, thread-in studs for hubs built for bolts, longer studs for spacers, and matching nuts.

Studs suit cars whose wheels come off often. The wheel hangs on the studs while the nuts go on, which makes it quicker to line up, and the hub’s own threads are no longer used at every change. The nut takes the wear instead and is easily replaced.

A press-in stud has a knurled shank, a band of fine splines that is pressed into the hub flange and stops the stud turning. The knurl must suit the hole: too small and the stud spins, too large and it can crack or distort the flange. A thread-in stud screws into a hub drilled for bolts, so no pressing is needed.

Choose by these points:

• Thread: metric M12x1.25, M12x1.5 and M14x1.5, and imperial 1/2-20, 5/8-11 and 5/8-18. Several of the heavy 5/8-18 kits are made for stock-car racing.
• Under-head length: measured from under the head to the tip, and listed in inches, such as 1.950, 2.700 or 3.200 in. Studs half an inch or an inch over standard length make room for spacers or thicker race wheels.
• Knurl: some kits give the knurl size, such as .568 in, or its length, such as 1.550 in. Compare it with the original stud before pressing.
• Material: some kits use 8740 chrome moly steel, a heat-treated alloy.
• Nuts and heads: 5/8-18 and 5/8-11 nut kits, closed conical nuts in M12x1.5 and M12x1.25, and a 12-point head on some kits.
• Vehicle kits: many kits are listed for one model and axle, front or rear, so start from the title.

Press studs in with a press, or draw them in with a nut and spacer, never by hammering on the threads. Check that each head sits flat against the back of the flange. Nut engagement at least equal to the stud’s diameter is a common minimum, so check it with the wheel in place. Torque the nuts to the stated figure, with the threads dry or lubricated as that figure assumes. Re-check after the first session, and replace any stud that is stretched, bent or damaged.