Torque specs lug nuts

I think mine says 76lbs & I feel the 76lbs. is too light. I do mine w/a torque wrench and it takes very little effort to get to 76lbs. I've upped it to 85lbs.

 

The 2nd Gen FSM, in several sections, states lug torque as "Torque: 113 N*m (1,152 kgf*cm, 83 ft.*lbf) [sic], should be lbf·ft or lb·ft.

But let's back up a little--lug nuts are torqued to specific values in order to achieve a desired clamping/retaining force to keep the wheel on. tightening the lug nut does this by stretching the lug stud (within it's range of elasticity) to pull the wheel and hub against each other--at that point the wheel/hub are clamped together as intended and there is (per the design engineers's calculations) sufficient remaining tensile strength in the stud to withstand externally applied forces wishing to separate the wheel from the hub (hitting curbs/rocks/etc.).

However once that desired clamping force has been achieved, and while further tightening of the nut does increase the clamping force, it also increases the tensile load on the stud, moving that load closer to the stud's yield point, meaning less external force would be required to load the stud to it's yield point.

So while should be no immediate problem with torquing them to 96 lb·ft (a15% overtorque), nothing will be accomplished anything other than to increase the tensile preload on the studs by 25% to 30%--i.e. 25 to 30% closer to their yield point and more susceptible to yielding (failure) via externally applied forces.

Going to 100 lb·ft (20% over-torqued) is ill-advised as it will increase the tensile preload on the stud by 35%+...

It is best to stick to the design engineer's recommendations, as neither they nor Toyota have anything to gain by specifying a too low a torque value--and quite a bit to lose should wheels start falling off...

 

TIS does state 76. Personally i prefer 85 ish with an extra little turn. So probably like 90.

 

Discount Tire used 300 lbs on two of the rear lugs, one on each side, last time they rotated the tires - genius.

 

83 ft lb

 

German spec...good’en tight.

 

I an surprised they did not shear--or did they?

 

And how did you measure the 300 lbs? Because I'm not buying that value. In my opinion the studs would snap off long before you reached that value. Even if they did over torque the lugs there is no way to measure what it was torqued to after the fact.

Break away torque is a whole different animal and cannot be used to determine the tightening torque.

 

I was going to stay away from this, but now that you bring it up...The only way to check the tightening torque on freshly torqued (see comments re: heat below) fasteners is to tighten them more and then guesstimate the original torque (typically 5%t o 10% less than what it took to tighten it more. Once it has cooled all bets are off.

Breakaway torque on a freshly tightened, still warm fastener is generally 80% or so of the tightening torque. Once the heat generated by the act of tightening has dissipated 100% to 120% is not uncommon...

 

90 ft-lbs

 

Sometimes I just can't help myself...

But as you said guesstimate.

 

I took it as he was simply implying they torqued the shit out of them, not actually torqued to 300lbs.

 

OK

 

For all things related to measurement, see A Dictionary of Units of Measurement by Russ Rowlett, UNC Chapel Hill.

 

A great link, I have bookmarked it. He does not appear to delve into derived units such as torque (lb·ft)--not to criticize however, as that would be another whole can of worms...

 

i just bring them as tight as i can get them , then a half a turn !!!!!!

 

Back to this old post: they torqued them tight enough to strip them, then did not even tell me about it, just let me drive away. We all make mistakes, - especially if you are in a hurry, just tell me about it. Discount tires "free rotation" ended costing me money and time and a big headache. I am very wary of bringing it back there.

 

Bump.

After getting my steelies rebalanced twice due to horrible shakes, I raised and re-torqued all four wheels to 83 ft-lbf as indicated in my manual. I could tell by the force needed to break the lugs loose they were not consistently torqued.
In retorquing, I used three steps to get to the 83 - first was 43, then 63 and then the final value 83.
(The truck rides much better now but not perfect..)

My question is, “how many steps do folks take to get to the final torque value?”

 

You have to make sure it's 83 ft-lbs. If it's 85 it'll explode

For torque spec, look in the manual or here: https://www.tacomaworld.com/threads/the-torque-spec-guide.318116/

 

This guy engineers.

Seriously though, thanks for posting this. Did the heavy lifting for me
Don't want these people to end up like the guy that broke all of his lug nuts yesterday...