If you’re going to be using your impact wrench to take the wheels of your vehicle on and off, firstly, don’t use your impact wrench to snug down the lug nuts! You’ll over-tighten them, which stretched out your lug nuts, and eventually they’ll snap (with some cars you’ll also warp the brake rotors). Use a torque wrench to make sure they go back on to the manufacturer’s suggested torque. But another thing you’ll need to keep in mind when you’re tightening down your lug nuts is to follow the right bolt pattern.
How do you tighten your lug nuts? Would you tighten one, then the one next to it, going around in a circle? It seems like a good idea, but there is a big problem with that method. The problem with going around in a circle, tightening each lug nut that is directly to the left or right, is that your wheel isn’t going to mount correctly, and then your wheel will have a wobble.
Imagine that you’ve got a 4 lug pattern (it’ll make up a square). It you tighten down the two lugs at the top, it will pull the top side of the wheel a little closer to the inside of the car, which causes the bottom of the wheel to be a little further away from the car (since it’ll pivot at the center of the wheel). Now it’s not mounted correctly, and tightening down the bottom lug nuts won’t correct it (unless your lug nuts stretch, or the wheel bends, both of which are bad). Again, when your wheel isn’t mounted correctly, it gets a wobble. That wobble wear out your tires faster, and can damage your car as well.
The solution to this tighten the first one, and then tighten the one that is opposite to the first one. Essentially you draw a straight line from the first lug, through the center of the wheel, and you tighten down the lug that sits on that same line, on the opposite side of the wheel.
That’s a pretty general solution, and it won’t work exactly, because with some bolt patterns your line will end up in between two lugs, but that’s the general idea that you will want to follow.lag bolts for wood
But now that you have the theory, here are the actual bolt patterns you will want to use. First you will label each lug nut 1, 2, 3, etc, going clockwise around the wheel. Then tighten the bolts in the following pattern:
4 Lug Pattern: 1 -> 3-> 4-> 2
5 Lug Pattern: 1 -> 4 -> 2 -> 5 -> 3
6 Lug Pattern: 1 -> 4 -> 6 -> 3 -> 5 -> 2
The technique that I’ve found works the best is to run through this pattern with your impact wrench and torque limiting socket. Then run through the pattern twice with your torque wrench. It’s important to run through the pattern twice just to make sure you don’t have any loose lugs. As you go through the pattern, the wheel gets pulled in and seated correctly, which can take pressure off the lugs you have already tightened, which makes them loose. Loose lugs are not a good thing!
So in closing, when you’re putting the wheels back on your car, tighten opposing lugs with the pattern we discussed above, and always double check your work!