Rick's Free Auto Repair Advice

Lug nut types

Lug nut types — Which type is right for your wheels?

If you’ve lost a lug nut and are shopping for a replacement, you’ll need to know the wheel stud diameter and thread pitch. You’ll also need to know the type of seat used on your wheels.

Wheel lug nuts — ball seat versus conical seat

Wheels can use a spherical (also referred to as a “ball seat), tapered (also referred to as a conical seat because it’s shaped like a cone), a flat seat, or a mag seat.

A tapered or conical lug nut should never be used on a wheel with a ball seat and vice versa.

ball seat versus conical seat

Lug nut types

In addition to spherical and conical seat types, carmakers and wheel makers also use a flat or mag style seat. A flat seat lug nut has a flange that tightens against a mating flat surface on the wheel.

A mag style lug nut has a wider washer that fits into a recess in the wheel.

Lug nuts are also available in open, acorn and capped acorn style.

lug nut types
Lug nut torque

Wheel studs can be damaged by applying too much torque to the lug nut. In addition to stud damage, using the wrong torque or uneven torque can cause lateral runout, which eventually causes brake pedal pulsation. ALWAYS use a torque wrench when tightening lug nuts.

Refer to a shop manual or this link if you don’t know y our lug nut torque specification.

If you can’t find the lug nut torque specification for you vehicle, use this general guide.

Stud Diameter Lug Torque
10 MM Stud 50 Foot Pounds
12 MM Stud 80 Foot Pounds
14 MM Stud 90 Foot Pounds
7/16 Inch Stud 75 Foot Pounds
1/2 Inch stud 85 Foot Pounds
9/16 Inch Stud 140 Foot Pounds
5/8 Inch Stud 160 Foot Pounds

Should you lubricate wheel studs or lug nuts?

Unless otherwise stated in your owner’s manual or a shop manual, lug nut tightening specs are DRY specs. NEVER lubricate the wheel studs or lug nut seats unless specifically advised to by the carmaker or wheel maker. Lubricating studs or lug nuts can cause over tightening and stud breakage.

Posted on by Rick Muscoplat


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