Lug Nut Torque Specs

by David McGuffin

Lug nuts are both a simple and essential part of your vehicle because they hold the wheels in place. It is important not to over-tighten the lug nuts because they may be extremely difficult to remove at a later time. Lug nuts that are under-tightened have the potential to unwind due to vibrations of the road and the rotation of the car's tire. As a result, lug nuts can become loose and fall off, potentially causing your tire to roll off of your car and causing significant damage to your vehicle.

Sizes of Lug Nuts

There are a variety of different sizes for lug nuts, each with varying torque requirements. It is important to use a torque wrench, set for the specific torque, to achieve the correct tightness when installing a lug nut bolt. 12-millimeter lug nuts should be tightened between 70 to 80 foot-pounds. 1/2-inch lug nuts should be tightened between 75 and 85 foot pounds. Lug nuts measuring a diameter of 9/16 inch should be tightened between 135 and 145 foot-pounds. Lug nuts measuring at 5/8 inches should be tightened between 125 and 135 foot-pounds.

Loosening Safety

If a lug nut has been over-tightened and is difficult to budge, it is important to practice safety for yourself and your vehicle while removing the lug nut. Never use any type of lubricant or penetrating oil, as residues could be left on your wheel studs, causing a potential safety hazard if tightened lug nuts are able to become loose while driving. Keep your tire on the ground instead of raising the wheel. The friction of the ground will help to prevent the wheel from spinning. As a last resort, stand on the tire iron or lug nut wrench to loosen the lug nut, carefully holding onto your vehicle to prevent yourself from slipping off the wrench and getting hurt. Alternatively, you can also use a breaker bar to help remove lug nuts that are seized on the vehicle's tire studs. Vehicles with expensive or upgraded rims often utilize wheel locks to prevent the rims from theft. A specialized wheel lock should be included with your vehicle's rims.

Tightening Safety

When tightening a lug nut, install all of the lug nuts by hand first, making sure that your tire is on evenly all the way around. Tighten one lug nut to its specified torque rating and then go directly across the bolt circle to the lug nut opposite the first lug nut. Continue this pattern until all of the lug nuts within the bolt circle are adequately tightened. If a lug nut or stud is stripped from over-tightening, take your vehicle to a professionally certified auto mechanic for the repair.

About the Author

David McGuffin is a writer from Asheville, N.C. and began writing professionally in 2009. He has Bachelor of Arts degrees from the University of North Carolina, Asheville and Montreat College in history and music, and a Bachelor of Science in outdoor education. McGuffin is recognized as an Undergraduate Research Scholar for publishing original research on postmodern music theory and analysis.

Photo Credits

  • photo_camera yellow car image by JoLin from Fotolia.com