CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Lug Nut Torque

Greetings:



I grew up being told to always torque my lug nuts to manufacturers specs and I still do. Once upon a time this was due to the use of much lighter (read weaker) components.



However, when I go to have ANY work done by a mechanic, even my tire sales guy, they just tighten them down with an impact wrench, no adjustment.



Is this still best practice, or should I still really be giving a darn?



Thanks!

Lug nuts must be torqued. It’s easy to do but most places don’t. They have no idea of what damage they are causing by overtightening or undertightening in some instances. You should give a darn. I would suggest buying a torque wrench and learn how to use it properly (never loosen any bolt with a torque wrench). Follow the torque pattern and happy motoring!

Best practice is to follow the manufacturer’s recs in the owner’s manual. Tightening with an impact wrench is a good way to warp the rotors or overtighten the lug nuts. When I change tires and wheels for Summmer and Winter I use an impact wrench to snug up the lug nuts. Then I tighten with a lug wrench and then use my torque wrench to get to 100 ft lbs as recd by the manuf’r. Don’t know about “once upon a time weaker components” but my car is 21st century and the manuf still recommends using a torque wrench to properly complete the job.

The trick is to find a shop to do the job right, my brake guys offer free check to protect the rotors after any tire rotation.

You are absolutely correct, and should give a darn! Low wheel torque can result in a wheel off scenario. High torque will stress the studs, equally as bad. Never tighten with an impact wrench unless using a torque stick and calibrated gun.

there’s no excuse for any shop not using a torque wrench & tightening lug nuts to specs. I worked at a Meineke Muffler shop for a month or 2 one time. It was a busy, volume exhaust shop. But we were required to torque lugs to specs and we had this huge poster on the wall that had all the applications & their lug nut torque specs.

At first I thought, geez, this is gonna be too time consuming, but actually it ended up taking like 10 seconds to find the spec on the chart & a few minutes to torque 'em down. The net extra time it took to do this couldn’t have been much more than a couple minutes per car. And of course, being a muffler shop, not every car had its wheel(s) removed to begin with. It’s do-able.

I am always concerned when I bring my car to someone to have work done. I have twice had new tyres installed by my local Discount Tire. I was very pleasantly surprised both times I have used them. When writing up the order they looked up the specs for my car (they had the right number) and when replacing the tyres, they used the air driver to put them on and then use a real torque wrench to tighten them. I checked one when I got home, and it was right.

As a result I use them and recommend them for my tyre work.

Note: I don’t know if all the chain’s locations will be as good and I still keep a close watch on them, but so far so good.

Costco tire centers also hand-torque all lug nuts.
Just one of the reasons why I buy my tires there.

I wonder how those NASCAR drivers can safely drive 200mph with wheels thrown on and nuts tightened with impact wrenches?

Those are NOT the standard fasteners that are on your grocery-getter. And, those are not the impact wrenches that you buy at Sears. Everything on those race cars is engineered to the unique purpose and stresses that those parts are exposed to, both at 200 mph and in the pits. You cannot compare ANYTHING you see on those cars to anything you drive daily.

I won’t speculate how many lug nuts I have tightened in my life. More than most, I’m sure. And although I once tried the torque sticks I wasn’t impressed and returned to flying by the seat of my pants with continued great success. I don’t know why lug nuts are such a great problem for some. Most of my work is on fleets so all the problems return here and there has never been a problem with broken studs, warped rotors, etc., ad nauseum. I have a few older customers whose wheels are installed by hand with a 4-way to ensure that if they had a flat they could get the wheel off in an emergency. All others are PROPERLY installed with an impact sans torque wrench.