Over-torquing Lug nuts.. Myth or Real

Nov 25th, 2018 9:06 am

#1

Asker123 [OP]: Deal Addict; Jan 7, 2014; 2678 posts; 535 upvotes; Manitoba

Nov 25th, 2018 9:06 am

So all mechanics are not equal.. right!!!
This mechanic to whom I took the car for tire swap, just used the pneumatic impact gun to tighten the nuts. He went in star fashion and did it once round for all five nuts.... Then he did one more round of tightening with the gun for the 4 nuts ( left out the nut with lock )
When I asked what about torque wrench, he said dont worry they wont fall... I said well must have over torqued then and must be difficult to loosen manually if required , he said dont worry they are 90 ft pound, only a woman might not be able to loosen but you can...I said well OK and drove off

So with two rounds using impact gun are they over tight? I have a breaker bar and torque wrench.. Should I loosen those a bit and re torque or just leave them in there...What hard can it cause..

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It will never be Oil or Gas or Wind or Solar or Electric. It will be Oil and Gas and Wind and Solar and Electric.

Nov 25th, 2018 9:08 am

#2

mebiuspower: Deal Fanatic; Oct 8, 2005; 6425 posts; 1955 upvotes

Nov 25th, 2018 9:08 am

Re-torque with a torque wrench.

Over tightening can warp your rotors.

+4

Nov 25th, 2018 9:16 am

#3

mrweather: Deal Fanatic; Aug 29, 2011; 9352 posts; 6491 upvotes; Mississauga

Nov 25th, 2018 9:16 am

You’re never supposed to use an impact gun to put lug nuts on because there’s no way to accurately control the torque that’s being applied.

Mechanics do it is because it saves time.

+7

Nov 25th, 2018 9:32 am

#4

bembol: Deal Expert; Jan 27, 2006; 19587 posts; 3240 upvotes; Woodbridge

Nov 25th, 2018 9:32 am

I guess did it's the last time you let him touch your car.

"I'll put up color bars before I'll put you in front of our cameras."

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Nov 25th, 2018 9:33 am

#5

azmongold: Sr. Member; Oct 2, 2017; 850 posts; 605 upvotes

Nov 25th, 2018 9:33 am

he's just another lazy mechanic.

I'll see you at the top, cause the bottom is too crowded

+1

Nov 25th, 2018 9:36 am

#6

Poulet: Deal Addict; Sep 2, 2006; 2636 posts; 1351 upvotes; Orleans, ON

Nov 25th, 2018 9:36 am

This could mean warped rotors...

Nov 25th, 2018 9:37 am

#7

Pete_Coach: Deal Expert; May 10, 2005; 36772 posts; 11164 upvotes; Ottawa

Nov 25th, 2018 9:37 am

mrweather wrote: ↑ You’re never supposed to use an impact gun to put lug nuts on because there’s no way to accurately control the torque that’s being applied.

Mechanics do it is because it saves time.

You can use an impact gun. Torque control can be achieved by air pressure or torque sticks.
I dare to say that 90% of shops use impact guns and without issues.

The most successful people are successful because they do not care about others’ opinions about them.

+8

Nov 25th, 2018 10:16 am

#8

Asker123 [OP]: Deal Addict; Jan 7, 2014; 2678 posts; 535 upvotes; Manitoba

Nov 25th, 2018 10:16 am

Poulet wrote: ↑ This could mean warped rotors...

well car will need new pads and rotors in a year anyways... last time only 3 mm pads were left
what about damage to the Bolts? and should I correct it
Doesn't driving loosens the nuts a bit anyways and I can just retorque after 100 kms or so

— — — — — — — — — — — —
It will never be Oil or Gas or Wind or Solar or Electric. It will be Oil and Gas and Wind and Solar and Electric.

Nov 25th, 2018 10:26 am

#9

pfbmgd: Banned; Feb 7, 2005; 4498 posts; 1190 upvotes

Nov 25th, 2018 10:26 am

If your mechanic does not use torque wrench find another mechanic . The air gun almost always over tighten the bolts . Can damage your rotor . Plus try to get the lug nuts off on th side of the road when over tight . Plus I'm sure the insurence for the garage has a clause in the coverage that torque wrench must be used when mounting tires . Most garages set the air gun below the specified tightness . The mechanic will then use the torque wrench to finish the job . Real good shops will tell you to come back after 100km to re cheque the the lug nuts .

<sig removed> by moderators . Yet no moderator told me they removed or why ?

+1

Nov 25th, 2018 10:31 am

#10

Asker123 [OP]: Deal Addict; Jan 7, 2014; 2678 posts; 535 upvotes; Manitoba

Nov 25th, 2018 10:31 am

pfbmgd wrote: ↑ If your mechanic does not use torque wrench find another mechanic . The air gun almost always over tighten the bolts . Can damage your rotor . Plus try to get the lug nuts off on th side of the road when over tight . Plus I'm sure the insurence for the garage has a clause in the coverage that torque wrench must be used when mounting tires . Most garages set the air gun below the specified tightness . The mechanic will then use the torque wrench to finish the job . Real good shops will tell you to come back after 100km to re cheque the the lug nuts .

I know .. stupid me... guess I will loosen them a bit and retorque... It does not need to be lifted right

— — — — — — — — — — — —
It will never be Oil or Gas or Wind or Solar or Electric. It will be Oil and Gas and Wind and Solar and Electric.

+2

Nov 25th, 2018 11:15 am

#11

ur_too_crazy: Sr. Member; Mar 17, 2006; 701 posts; 433 upvotes

Nov 25th, 2018 11:15 am

Most garages would rather over tighten lug nuts than risk a customer's wheel flying off while they're driving it on the highway (I know I would). I don't see how over torquing a lug nut 10-15 ft lbs or so over spec in a criss cross pattern can warp a rotor but I am not a mechanical engineer either.
I do all tire swaps myself. My wife's Nissan Rogue calls for 80 ft/lbs lug nut torque, which I always found on the low side. The first few times I swapped her tires, there was always some lug nuts that worked themselves dangerously loose (yes my torque wrench was well calibrated at the time). Never understood why. Now when I change her wheels, I torque it to 90 and sleep better at night (no warped rotors either)

Nov 25th, 2018 11:33 am

#12

Pete_Coach: Deal Expert; May 10, 2005; 36772 posts; 11164 upvotes; Ottawa

Nov 25th, 2018 11:33 am

ur_too_crazy wrote: ↑ Most garages would rather over tighten lug nuts than risk a customer's wheel flying off while they're driving it on the highway (I know I would). I don't see how over torquing a lug nut 10-15 ft lbs or so over spec in a criss cross pattern can warp a rotor but I am not a mechanical engineer either.
I do all tire swaps myself. My wife's Nissan Rogue calls for 80 ft/lbs lug nut torque, which I always found on the low side. The first few times I swapped her tires, there was always some lug nuts that worked themselves dangerously loose (yes my torque wrench was well calibrated at the time). Never understood why. Now when I change her wheels, I torque it to 90 and sleep better at night (no warped rotors either)

Proper torquing (installation) technique using the star or criss cross pattern will prevent any rotor warping, that is one of the reasons you do this pattern, to distribute the load evenly.
Also, every shop will tell you to come back or have someone torque check (not re-torque) the nuts after 100 kms or so and, you should also do this at home. The amount you torque it to is not as important as the torque check.

The most successful people are successful because they do not care about others’ opinions about them.

+2

Nov 25th, 2018 12:02 pm

#13

Pete_Coach: Deal Expert; May 10, 2005; 36772 posts; 11164 upvotes; Ottawa

Nov 25th, 2018 12:02 pm

Asker123 wrote: ↑ I know .. stupid me... guess I will loosen them a bit and retorque... It does not need to be lifted right

Torque checked....not re-torqued.
Torque checking is making sure the torque has not changed and is as it should be. Re-torquing is loosening the nuts (bolts) and then torquing them again which, will require a torque check again 100 kms or so down the road.
No, it does not have to be lifted off the ground to do this.

The most successful people are successful because they do not care about others’ opinions about them.

+3

Nov 25th, 2018 12:23 pm

#14

billford: Deal Addict; Feb 6, 2011; 2222 posts; 2700 upvotes

Nov 25th, 2018 12:23 pm

Asker123 wrote: ↑
So with two rounds using impact gun are they over tight? I have a breaker bar and torque wrench.. Should I loosen those a bit and re torque or just leave them in there...What hard can it cause..

Don't loosen, check all wheels with an accurate torque wrench.

Plus air guns are not supposed to be used on wheel locks, that's what is says on the instruction that nobody reads.

Let us know what you find.

+1

Nov 25th, 2018 1:45 pm

#15

jzmtl: Deal Addict; Jun 14, 2008; 4440 posts; 3329 upvotes; Montreal

Nov 25th, 2018 1:45 pm

No mechanic will hand torque all your lug nuts with a torque wrench, especially with the tire season on.

If you want that do it yourself in the driveway.

+3

Nov 25th, 2018 2:00 pm

#16

iSimple: Deal Guru; Sep 13, 2007; 10848 posts; 6325 upvotes

Nov 25th, 2018 2:00 pm

Time is money

+3

Nov 25th, 2018 2:25 pm

#17

otaknap: Deal Addict; Feb 26, 2016; 1541 posts; 515 upvotes; Vaughan

Nov 25th, 2018 2:25 pm

i would definitely re-torque.

Nov 25th, 2018 2:27 pm

#18

Pete_Coach: Deal Expert; May 10, 2005; 36772 posts; 11164 upvotes; Ottawa

Nov 25th, 2018 2:27 pm

otaknap wrote: ↑ i would definitely re-torque.

Wrong....torque check, not re-torque.

The most successful people are successful because they do not care about others’ opinions about them.

Nov 25th, 2018 2:29 pm

#19

lazybum131: Sr. Member; Nov 30, 2003; 511 posts; 79 upvotes; Edmonton

Nov 25th, 2018 2:29 pm

Re-torque them with your own breaker bar and torque wrench, and torque check 50-100km later. You're mechanic is wrong.

As for what harm, when I first bought my new-to-me car, I needed to get new winters. Kal-Tire torqued them to 140ft-lb, insisted that was what their system said was the torque value for my car. Everywhere else said it should be 125ft-lb. I got vibration under braking that wasn't there before. Bought my own torque wrench on sale and re-torqued them, well what do u know, the vibration went away.

+2

Nov 25th, 2018 2:33 pm

#20

otaknap: Deal Addict; Feb 26, 2016; 1541 posts; 515 upvotes; Vaughan

Nov 25th, 2018 2:33 pm

Pete_Coach wrote: ↑ Wrong....torque check, not re-torque.

haha.. sorry, that's what i meant. i would loosen the nuts with a breaker bar and just torque it using my torque wrench to the specs as per the manual.