Torque Specs, Lug Nuts and Fasteners Done Right

Under-tightened fasteners loosen and over-tightened ones stretch or break. Torque is the standard way to get a bolt to the right clamping force. This guide covers how a torque wrench works, how to tighten lug nuts, why lubrication changes the answer, and where to find the right figure.

What torque does

When you tighten a bolt, you stretch it slightly, and the stretch is what clamps the parts together. Torque (twisting force) is a convenient proxy for that clamping force. A bolt tightened too little can vibrate loose and a bolt tightened too much can stretch past its limit, strip its threads or snap. The figures in a service manual are set to stretch each bolt to an effective, safe level.

Using a torque wrench

Use a wrench whose range suits the job; the middle of its scale is the most accurate.
Pull smoothly and steadily. Jerking gives a false reading.
Click-type wrenches should be set to the value and stop pulling when they click. Store them at the lowest setting, unlocked, to preserve accuracy.
Do not use a torque wrench to loosen bolts, and do not use extensions or adapters without accounting for their effect.
Have the tool checked or calibrated periodically.

Lug nuts and wheel studs

Wheels must be tightened evenly. Tighten the nuts in a star (criss-cross) pattern, in two or three stages: snug them by hand, then bring them to about half torque, then to full torque. Use a torque wrench for the final tightening instead of an impact wrench, as impact tools can over-tighten and stretch studs or warp brake rotors. Recheck the torque after the first 50 to 100 miles, since the wheel can settle against the hub. Typical figures are roughly 80 to 100 ft-lb for many passenger cars and 100 to 140 ft-lb or more for light trucks, but they vary, so use your vehicle's specification. The Lug Nut Torque Lookup gives a starting reference by thread size and vehicle type, and the Lug Pattern Lookup helps identify your bolt pattern.

Keep the mounting surface and the nut seat clean and free of rust.
Use the nut type designed for the wheel (conical, ball or flat). Mismatched seats cause loosening.
Do not put oil or anti-seize on lug studs unless the manufacturer says so, as lubrication changes the clamping force for a given torque.

Bolt grade and size

Bolts are rated by strength. Metric bolts show a property class on the head, such as 8.8, 10.9 or 12.9, where the higher number means higher tensile strength. Inch bolts use SAE grades marked with radial lines on the head: no marks is grade 2, three lines is grade 5 and six lines is grade 8. Higher grades allow higher torque, but only up to what the threads and the clamped parts can take. Never replace a high-grade bolt with a lower-grade one in a critical place such as suspension, steering, brakes or engine internals.

The Bolt Torque Lookup gives general torque values by size, thread pitch and grade for situations where the manual does not list a figure. Manufacturer specifications always take priority for a particular component.

Lubrication changes the torque

Torque figures assume a certain thread condition, usually clean and dry or lightly oiled as the manual states. Oil, anti-seize or thread-locker reduces the friction in the threads, so the same torque produces more clamping force and can over-stretch the bolt. Many service manuals give a reduced value when threads are lubricated. If you are using anti-seize on a bolt the manual specifies dry, reduce the torque, often by 20 to 30 percent, but check the manufacturer's guidance first.

Torque-to-yield and angle bolts

Some engine bolts, such as head bolts and connecting-rod bolts on many modern engines, are tightened to a torque and then an additional angle. They are designed to stretch permanently and must be replaced after each use. Reusing them risks failure. Follow the sequence in the manual exactly, which usually works from the center outward in a spiral.

Threads, taps and holes

When repairing damaged threads, you may need to drill and tap a hole. The Tap Drill Size Lookup gives the drill size for each tap and thread type. Cleaning threads with a chaser rather than a tap removes dirt without cutting new metal. Always check threads are clean before measuring torque.

Other common specifications

Spark plug torque and gap; see the Spark Plug Gap Chart. Aluminum heads are easily damaged by over-tightening.
Oil drain plugs, which strip easily.
Caliper bolts, axle nuts and suspension fasteners, which have exact specifications.

Common mistakes

Tightening lug nuts in a circle instead of a star.
Using an impact wrench for final torque.
Lubricating threads that the manual specifies as dry.
Reusing torque-to-yield bolts.
Guessing a figure instead of looking it up.

Frequently asked questions

What is the right torque for lug nuts?

It depends on the vehicle and stud size, so check the owner's manual. Many passenger cars use roughly 80 to 100 ft-lb and many light trucks 100 to 140 ft-lb or more.

Should I put anti-seize on wheel studs?

Generally not, unless the manufacturer says so. Lubrication increases the clamping force at a given torque and can overstretch studs, so a reduced torque would be needed.

Can I reuse torque-to-yield bolts?

No. They are designed to stretch permanently when tightened, and reusing them risks breakage. Replace them each time.

Tools used in this guide

More guides

Figures in this guide are general guidance for planning. Always follow your vehicle, tool and product manufacturers' instructions and local codes, and read our disclaimer.