Lug Nut Torque
Tech > Lug Nut Torque
When I was in my teens my Dad taught me how to torque wheel lug nuts properly. He learned himself at a young age from a heavy equipment mechanic, who explained that fasteners torqued in this way can be relied upon not to loosen... especially useful when those fasteners are difficult to access. The method is a combination of pattern and gradual application of torque. I've used it for since the first time I put a wheel on a car and it has served me well.
The torque pattern is pretty simple:
In combination with the pattern is the gradual application of torque. One third of the spec for all lugs, then two thirds, then full torque.
So when I'm installing a trailer tire, here's my procedure:
- Place the tire on the hub - I usually do this from a sitting position, balancing the tire on my feet.
- Finger-tighten the lug nuts while shifting the tire with my feet - this helps to ensure that the cones of the lug nuts centre the wheels on the lugs. I repeat this, moving from one nut to another, until all are finger-tight. At this point I'll snug them up a bit more with breaker bar and socket, but not much.
- Lower the trailer until all the weight is on the tires.
- Set the torque wrench to one third of the spec. In my case, 33 lb-ft (the spec is 100 lb-ft) and torque the lug nuts in the pattern shown above.
- Set the torque wrench to two thirds (66 ft-lb) and torque the nuts in the same pattern.
- Set the torque wrench to the full spec (100 ft-lb) and torque in the pattern once more.
Nowadays it's common for car and RV repair shops to warn you to check lug nut torque after driving for 100 km. With this method, that's not necessary; I've done spot checks and have never found a loose lug nut. And when I get a vehicle back from such a shop, I always loosen and re-torque the wheels this way.