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roger wiegand
11-14-2014, 9:13 AM
So I probably should have learned this long since, but what's the correct method for re-torquing lug nuts? When I pulled my summer tires off I noticed a couple seemed loose, so decided to follow the recommendation to put the winter tires on, torque them, then drive a day or two and re-torque them. Do you loosen the nut first to get an accurate reading when you re-tighten, or just leave them tight and torque again? Do lug nuts ever spontaneously tighten and require loosening? (seems like it could happen, sometimes it seems to take gorilla strength to get them off)

Thanks!

Val Kosmider
11-14-2014, 12:26 PM
To re-torque, simply put the wrench on and tighten. Do not loosen them, and the retighten. THAT would be a never ending circus.

If the metal wheel flexes it is possible, but unlikely, that the lugs would "spontaneously" tighten or loosen. More likely loosen from flexing and heat build up. That is why you re-torque after a small amount of driving.

When you torque the lugs, make sure to use a diagonal pattern. Do not simply go around the pattern from one to the next.

Myk Rian
11-14-2014, 12:34 PM
I have never re-torqued wheels. Never heard of the requirement to do so.

Ken Fitzgerald
11-14-2014, 12:46 PM
Roger,

Professionally I had to actually take a class about "torqueing" something to specifications and my torque wrench set was calibrated annually. Contrary to what a lot of people think, including myself until I took the class and experienced it for myself, it's easy to over torque something.

The key to torqueing something is a two step process:

1. There is typically a pattern to use. In the case of more than 4 lug nuts on a wheel, try to do a star pattern torqueing non-neighboring nuts first, torqueing them to about half the specified torque, then torque the remaining nuts to the same value. If you only had 4 lug nuts you would do non-neighboring first, then do the remaining nuts, again to about 1/2 the specified torque.

2. Then repeat the previous process to the final torque value but sneak up on it. When you "sneak" up on the final value, don't try to do it quickly and don't go back to check it. The instructor informed us and we actually experienced "over torqueing" if we went too fast or went back to check the torque.

Bruce Page
11-14-2014, 12:51 PM
My mechanic told me that aluminum rims should be re-torqued after 100-200 miles. Steel rims do not require it.

roger wiegand
11-14-2014, 12:57 PM
Thanks all, that makes sense--sometimes I over-analyze problems. Learned the star pattern long, long ago, but never had anything as fancy as a torque wrench in my primary car repair years-- just "oops it fell off", "feels pretty good", and "broke the &(^%! bolt"

Chris Padilla
11-14-2014, 1:03 PM
The most important thing about torquing tires to whatever value the manufacturer asks is to do it under load. So let's say you rotate your own tires. Get the tires on there and snug all the lug nuts down good but not past their torque value. Pull the jacks, jack stands, etc. so the car is resting on the tires like normal. Now torque the wheels to the correct value. Of course, torque in the star pattern as was pointed out a couple of times.

Pat Barry
11-14-2014, 1:34 PM
My experience is that when they torque those suckers on at a tire place or dealership they are much tighter than I can get by hand.

Erik Loza
11-14-2014, 1:37 PM
I always torque them in a criss-cross pattern and also, use anti-seize paste on the threads. Never had a lug nut loosen on me but it seems like it's a possibility with the "ultralight" aluminum wheels that are popular on sport-compact cars.

Erik Loza
Minimax USA

Lee Schierer
11-14-2014, 6:09 PM
My experience is that when they torque those suckers on at a tire place or dealership they are much tighter than I can get by hand.

Many shops use pneumatic impact drivers and if they don't set the air pressure correctly for the needed toque, typically they will over torque the lugs. The tire shop I use now, removes the nuts with the impact driver, but they only hand torque the nuts when they put the wheel back on.

Aluminum wheels can relax, just like aluminum wiring, when it is put in compression. Having aluminum wheels retorqued after 50-100 miles is a really good idea.

Tom M King
11-14-2014, 6:54 PM
If you use lubricant on threads, as in graphite in anti-seize, the torque needs to go up. Torque charts for bolts have two values. One for dry, and one for lubed.

Tom Stenzel
11-14-2014, 8:20 PM
If you use lubricant on threads, as in graphite in anti-seize, the torque needs to go up. Torque charts for bolts have two values. One for dry, and one for lubed.

Lubricated threads are tightened to a LOWER torque to create the same downward force. I think you know that, it just came out wrong.

I've always lubricated the lugs on my cars without any problems as long as I'm the only one to touch the wheels. The problems start when a shop takes the lubricated lugs and cranks them down with their uncontrolled air wrenches. The results are stretched or snapped off studs.

So yes, lubricated lug nuts can cause problems. Just not directly.

I've never retorqued the nuts. But then being a Detroit boy, I've never had alloy wheels on a car. Still didn't stop our west side gang from swiping my Cavalier and absconding with the cheap steel wheels.

-Tom

Jerome Stanek
11-15-2014, 7:45 AM
You can get impact torque limiters. My buddy has a big one for his semi wheels it was required for warranty for the rims

Fred Perreault
11-15-2014, 8:02 AM
Having worked a lot on my own heavy equipment, I believe that Caterpillar's torque specs cause the bolts to actually stretch some by design and maintain a sort of tension. All Cat fasteners (nuts and capscrews) are grade 8, and Caterpillar recommends that one should never re-use the fasteners, as their strength has been compromised due to the stretching. Working on the undercarriage of our D-6 and D-8, we had to bring the 1.125" coarse thread bolts to 1280 lbs. That was done using guesswork. But we did remove and re-install the hardware with a 4-1 torque multiplier. It was a gearbox with a 3/4" square drive on the backside for a ratchet or breaker bar, and a 1" square drive on the drive side for 1" sockets...... and a 6' pipe for leverage. This was of course done in our own small shop. Caterpillar's shops have the latest and greatest tools and accessories. We have 4 different sizes of ratchet type torque wrenches, the biggest only goes to 250 lbs. We are always checking and re-tourqeing the fasteners holding the wheel rims on the dump trucks and trailers. I think that the weight on the trucks flexes the rims or something, because they frequently loosen up and we replace the hardware once in a while as well.

Rick Moyer
11-15-2014, 9:01 AM
My mechanic told me that aluminum rims should be re-torqued after 100-200 miles. Steel rims do not require it.


I have never re-torqued wheels. Never heard of the requirement to do so.
I just changed a wheel on my utility trailer last night. The mfg says to re-torque the lug nuts after 10-15 miles and again after 50 miles, (if I remember what I read last night correctly). These are steel wheels.

Thomas Hotchkin
11-15-2014, 11:25 PM
How often do you have your torque wrench recalibrated? Should be right after you drop it the first time for dial and click type. I good torque wrench (Snap-on, Proto) are good to about 3% of the desired torque setting, on click type torque wrenches. If you have never had it recalibrated, you may be off the desired torque setting by 10 to 20 percent. Click type are not great on retorqueing they work best coming slowly to desired set point, we were taught 90 degree swing was best. Hope this helps.

Larry Edgerton
11-16-2014, 6:36 AM
Having worked a lot on my own heavy equipment, I believe that Caterpillar's torque specs cause the bolts to actually stretch some by design and maintain a sort of tension. All Cat fasteners (nuts and capscrews) are grade 8, and Caterpillar recommends that one should never re-use the fasteners, as their strength has been compromised due to the stretching. Working on the undercarriage of our D-6 and D-8, we had to bring the 1.125" coarse thread bolts to 1280 lbs. That was done using guesswork. But we did remove and re-install the hardware with a 4-1 torque multiplier. It was a gearbox with a 3/4" square drive on the backside for a ratchet or breaker bar, and a 1" square drive on the drive side for 1" sockets...... and a 6' pipe for leverage. This was of course done in our own small shop. Caterpillar's shops have the latest and greatest tools and accessories. We have 4 different sizes of ratchet type torque wrenches, the biggest only goes to 250 lbs. We are always checking and re-tourqeing the fasteners holding the wheel rims on the dump trucks and trailers. I think that the weight on the trucks flexes the rims or something, because they frequently loosen up and we replace the hardware once in a while as well.

You are correct, bolts do stretch. In Smiths book on fasteners he says to think of bolts as a spring. In our racing engines all the critical bolts were measured for bolt stretch before assembly to make sure they were within tolerance. If you are in the business I highly recommend Smiths book, http://www.amazon.com/Fasteners-Plumbing-Handbook-Motorbooks-Workshop/dp/0879384069. I learned a lot from this book and still use it as a reference. It taught me I was doing a lot of things wrong because I did not understand the basics.

Larry

Moses Yoder
11-16-2014, 7:29 AM
For insurance purposes, it seems like the re-torquing would need to be witnessed and certified by a notary public.

Jason Roehl
11-16-2014, 8:46 AM
If your tire shop puts lug nuts on with an impact wrench WITHOUT a "torque stick", dump them and find another shop. They're going to at least weaken your studs, which will possibly break off at a very inopportune time.

It's common for alloy wheels to need to be re-torqued after about 100 miles.

My ex-BIL works for Cummins. Their research was that a specific torque on a bolt was very difficult to obtain and that the best approach was a spec for "torque plus angle". You'll often see cylinder head bolts specified like this. The last time I torqued down a cylinder head (on a '90 F150 with a 5.0L engine), the spec was something like 60 ft-lbs + 90.

I do all my own brake work, and when I've tightened the lug nuts to spec with my ~$100 Craftsman torque wrench, I've not had a problem, save for the one time I didn't re-torque some alloy wheels 100 miles later. Our Chrysler minivan gets the (5) lug nuts torqued to about 100 ft-lbs, and my 3/4-ton Ford van gets its 8 lug nuts tightened to 140 ft-lbs (that one's a chore!).

Ole Anderson
11-16-2014, 6:02 PM
And when you are done using the clicker style torque wrench, relieve pressure on the spring. Like your band saw. Personally, I run the nuts up to just past loose with the rattle gun, let the jack down then torque them. And first time you get to torque down a cylinder head with a nice torque wrench, it can be a bit of an ethereal experience. You become one with the tool...:cool:

Art Mann
11-16-2014, 6:22 PM
. . . And first time you get to torque down a cylinder head with a nice torque wrench, it can be a bit of an ethereal experience. You become one with the tool...:cool:

I like that description.:)

Jim Koepke
11-16-2014, 8:54 PM
Lots of good information to ponder.

I haven 't changed my own wheels in quite a while. But besides using my body weight and a tape measure to set the torque, they would get checked after driving a bit.

It is cheap and easy insurance.

jtk