Wheel Torque: Why Re-Torquing After Service Matters

Overtightened lugs warp rotors and stretch studs. Undertightened ones come loose. Both are avoidable.

Lug nut torque is one of those things that seems trivial until it is not, and it goes wrong in both directions.

Too tight

• Stretched studs. A stud is a fastener with an elastic range. Past it, it stretches permanently and it will eventually fail.
• Warped rotors. Uneven clamping distorts the hub face, which produces the thickness variation people describe as a warped rotor.
• Seized nuts. A lug driven on with an impact gun at full setting can be genuinely impossible to remove at the roadside with the vehicle's own wrench — which is a problem at exactly the wrong moment.
• Damaged alloy wheels. Overtightening deforms the seat area.

Too loose

The wheel works against the hub, the holes elongate, the studs shear, and the wheel comes off. It is rare and it is catastrophic.

Doing it right

1. 1Clean the hub face and the wheel mating surface. Rust and debris there is a leading cause of a wheel loosening.
2. 2Start every nut by hand to avoid cross-threading.
3. 3Tighten in a star pattern, not around the circle, so the wheel seats evenly.
4. 4Bring them up in stages rather than one at a time to full torque.
5. 5Finish with a torque wrench to the vehicle's specification. An impact gun is for removal and for running them down, not for final tightening.
6. 6Do not put anti-seize or oil on the threads unless the manufacturer specifies it — lubricated threads reach a much higher clamping load at the same torque reading.

Signs something is wrong

A clicking or clunking that changes with speed, a vibration that appeared right after a tire service, visible rust streaks running out from the lug holes, or a wheel that looks slightly off-centre. Any of those means stop and check.

We torque to specification with a wrench on every wheel we fit, and we say so because plenty of places do not.