torque spec for lug nuts

The Chevy half-tons use a heavier lug, even though the bolt pattern is the same. I am not sure if they are metric or not, but they are 14mm or the closest Imperial size. Tacomas use 12mm. 85 ft lb is right for 12mm lugs, 115 ft lbs for 14mm.

 

Yeah, 14mm on the chebby.

 

Chevy is known for the wheels falling off. LOL

/joke

 

They were 12mm. I could take one off and thread it on to the tacaoma. Different style lugnut but same size.
I think toyoata may be wrong with that 85 ft lb torque value.
Just like they were wrong about the u-bolt torque value.

 

85 ft lbs plus or minus is dead on for 12mm, not just Toyota but any brand. The threads on 12mm lugs are not as heavy as on 14mm and 115 ft lbs is pushing the threads to failure on them. I don't have a Chev, but every one I have ever seen had heavier lugs than Tacos... when I sold my old rims to a Chev guy he couldn't take the tuner nuts I had because they are too small. I would think the most likely explanation for your K1500 having 12mm lugs is that someone changed the lugs, that would explain one truck being different from the rest, and also why your manual listed 115 ft lbs (it was written for 14mm lugs).

85 ft lbs is definitely good for 12mm, 115 ft lbs could be dangerous.

 

Gm offers a heavy duty suspension option known as a "heavy half' to some folks. Bigger brakes, better suspension, and likely 14mm lugs. I called them 5/8 ton trucks
My truck did not have this option, I had 12mm lugs and the manual stated 115 ft lbs. I owned that piece of shit for 21 years and always torqued the wheels to 115. At that torque, it's still possible to to loosen the nuts with just a 1/2" breaker bar.

 

In over 19 years of driving, I have never torqued lug nuts and never had an issue, but I will probably start. I guess I am pretty good at judging it with my arms.

 

Could be different grades of steel, could be just different engineering considerations. Once the desired clamping force is attained and the nut is in no danger of "backing off" and loosening there is no point in further tightening...

 

It is not really all THAT critical. It is more important that they be tightened sequentially in a staggered pattern; all be tightened to approximately the same torque; and that they are tight enough to not back-off.

All that said with alloy wheels I always use a torque wrench--except when at the side of the road changing a flat...

 

Yea that’s why I will start, I have aluminum wheels. But yea, I have always just done a star pattern and cranked em down tight.

 

The star pattern is critical and equal torque on each lugnut is very important, but 85 ftlbs just seems low to me.
Tire shops are notorious for cranking the lugnuts down way too tight. I think the studs are designed for a little extra torque.
Just my opinion but I sleep better with my nuts a little tighter.

 

This is all back-of-a-napkin stuff based on my memory of such things, assumptions, and over-simplifications:

85 lb·ft on a M12 x 1.25 stud (assumed to be metric class 10.9) will create some 10.5k pounds of clamping force with the stud loaded to approximately 50% of its tensile load rating of 21.5k lbs (2004 edition of The Machinist's Handbook)--a good place to be in the overall scheme of things.

Times 6 studs that's 66,000 pounds of force holding the wheel to the hub with the remaining 50% of the studs' maximum tensile strength, another 66k lbs, available to hold the wheel on. I.e. in theory it would take 66k lbs additional load to cause all studs to fail simultaneously.

Now let's torque them to 100 lb·ft which will increase the clamping force to 12k to 13k lbs. (some 60% of the stud's tensile rating) with just 40% of the stud's strength (9k lbs) remaining. So with the added tightening torque (and again in 110% "back-of-a-napkin" theory) it would now take just 56k lbs added load to break all 6 studs.

So based on assumptions taken all that over-tightening the studs has done is reduce the studs' remaining capacity to actually hold the wheel on--you decide...

 

Why the wide torque variation out there in truck world?

My 2016 F150 owners manual, with 6 studs, says 150 ftlbs.

Four wheels, six nuts each at 150ftlb's, and you've got yourself a real workout when rotating tires.

 

Your F-150 has 14 mm wheel studs (M14 x 1,5), they have a 36% larger cross-section than the 12 mm studs on the Tacoma. Also the Ford bolt circle is ironically "pure" metric at 135 mm (5.315") v the Taco's imperial sized 5.5" (139.7 mm).

I.e. they are different vehicles differently dimensioned, designed by different engineers, with different design criteria and goals...

 

Straight from the 2017 manual.

 

Like many here, I needed to stand on a 3 ft pipe on my breaker bar to remove the lug nuts on my new "used" 2007. Then all four wheels were seized to the hubs. Took two days. One of the nuts disintegrated. Another useful thing: 21mm lug nut, but without the chrome cover, a 19mm socket will work (had to tap it on). I'm going with the factory spec on these.

 

Here's something I use when I don't see a torque spec called out. It's from a well known manufacture and use at your own risk. It hasn't fail me yet. My guess the difference between the Tacoma and Chevy is the grade of the stud used.

 

Hi

83Ft-Lbs sounds good to me.

I just had our 2021 come in the shop with a shake when brakes applied and found the lug nuts seriously over torqued.

Removed all wheels and re-torqued I also use a defiant pattern the depicted here and I hand tighten all wheel lugs to bring the wheel flat against the hub and centered in the lug nut taper before torquing but would think it would give the same results.

I do agree that most 6 lug light truck and trailer wheels spec out 115 Ft-Lbs on aluminum wheels.

Phil P