: Lug nut torque at dealer or tire shop



VaRob
05-05-2013, 11:30 PM
I read the thread about aluminum lug nuts with interest and it raised a question. Several people mentioned that shops tend to over-torque the lug nuts with their impact wrenches. How big of a problem is this? I've never had a vehicle suffer any damage that I know of from having my tires rotated by a shop.

I am not in a position to rotate my own wheels, but I do have a good torque wrench that I bought for a travel trailer. If this is something I should be concerned about, is there any benefit to loosening and re-tightening the lugs right after I bring the Volt back from a tire rotation? I guess the question amounts to whether the 'damage' is from the initial over-tightening or from being over-tightened over time. Is it worth the trouble to do that?

KNI
05-05-2013, 11:53 PM
Only heard about these issues with over torquing.

- Bolts break on drive or mostly at next tire change, pain to replace (common)
- Rim gets deformed and pushes to internal parts (break disk?) (haven't seen though).
- Rim gets deformed, bolt breaks or no-retorque after 100 miles and the rim "lives". Makes noise and softens the rim upto a point where you can bend it with fingers (seen one). Usually ends up as three wheeler if not fixed.

SharkVolt
05-05-2013, 11:58 PM
I think Chevrolet recommends 100 lb/ft torque.
The industry standard for grade 5 1/2" bolts is about 65-80 lb/ft. of torque.
I have gone by that for many years on all my cars, (including race cars) and have never seen a problem with them at that spec.
I have gotten wheels back from various tire shops where I know they used a 1/2" impact wrench to put wheels on with. The problem is that if you hold the trigger more than a second, they can apply as much as 250 lb/ft. of torque!

Finally, a few years ago, after one shop bent a couple of $250 aluminum racing rims trying to get tires mounted on them, we bought our own tire changer machine and a balancer, and we do all our own tire work now. And the only impact wrench we use is a 3/8" butterfly one, which only puts out a maximum of 65 lb/ft torque, and then we finish with a manual click torque wrench to about 80.

timlange3
05-06-2013, 07:14 AM
All the shops I've dealt with use torque sticks on their impact drivers. Torque sticks are a bit expensive, but really do a good job of limiting the torque value to what is stated on the stick. I've checked my lug nuts afterwards and they were within a couple lb-ft of the correct value. Torque sticks work by flexing at the proper torque setting enough so the impact driver no longer rotates the nut.

VaRob
05-06-2013, 09:02 PM
Thanks, Tim. I think I'll just assume that a high-quality tire shop uses torque sticks and trust them to do it right.

Upper5Percent
05-06-2013, 09:05 PM
All the shops I've dealt with use torque sticks on their impact drivers. Torque sticks are a bit expensive, but really do a good job of limiting the torque value to what is stated on the stick. I've checked my lug nuts afterwards and they were within a couple lb-ft of the correct value. Torque sticks work by flexing at the proper torque setting enough so the impact driver no longer rotates the nut.

Actually the price has come down...:)
http://www.torquestick.com/cart/

ChevyEMF
05-06-2013, 09:36 PM
Didn't happen on my Volt, but my wife's 528 needed new summer tires last spring. We went to the independent shop we used for years. Winter comes along and I didn't plan ahead, we were taking the Bimmer on a holiday trip the next day and I wanted the Blizzaks on. Too short notice for the shop, so I called the Valvoline rapid oil change, they said a tire rotation was twenty bucks, swapping wheels would be the same. They could not get the wheels off. I won't say how hard they tried since they said if the impact wrench wouldn't work, they weren't supposed to do anything else, but they did try. They really did try. I took the car home to do it myself, which I obviously didn't want to do. Broke my 1/2 drive socket using a cheater bar to no avail. Went to pick up a 14 inch socket driver. Used a five foot cheater and was worried about what would break first. Fortunately it was the lug bolts loosening. Broke each bolt loose, re-tightened them and took it back to valvoline ( I just didn't want to spend a lot of time jacking the car up on a winter day). They used torque sticks and swapped wheels in a few minutes. I have no idea how the first shop torqued those wheels so tight. I haven't been back. Swapped the wheels back this spring myself, but it was a nice day.

msirach
05-06-2013, 09:59 PM
I rotate my own tires which is done maybe one time over the life of the tire. If I get a new set, I either remove tires and rims at home or I watch while they install the new ones at the shop.

USe-car
05-07-2013, 08:31 AM
I rotate my own tires which is done maybe one time over the life of the tire. If I get a new set, I either remove tires and rims at home or I watch while they install the new ones at the shop.

I agree. You should always watch (if you can) then your tires are changed. Especially during balancing. Especially at Discount Tire. There have been numerous times when I see the balance machine get within .25 ounce, and the technician says "good enough" and begins to reinstall the wheel. Not good.