Lug nut torque at the track

[drummerboy]

I was going round and round clockwise pushing the tires to their limit over a dozen runs and obviously getting more wear on the left front than the right front. My intent was to rotate the tires every few runs, but I noticed something that made me pause.

They're always torqued to 150lb-ft as usual and doublechecked before first run. After 3 runs I went to check the torque on one of rear's lugs before swapping, and it wanted to turn a significant amount before getting close to 150. Checked one of the fronts, got the same. I assumed at that point that the lugs, nuts, and wheels are all more pliable with extreme heat in them. Not wanting to set them to the cold equivalent of somewhere between 200-300lb-ft and snap a lug off, I left everything else alone and abandoned the idea of rotating for the day in order to first ask here what the deal is. The next morning (before another full track day) I loosened everything a bit and retorqued to 150 again with everything cold (and completely forgot to rotate the tires at that time )

Note: I usually torque the lug nuts to 125 first and then go back around to take them to 150. If you ever do this, you'll notice the tiniest fraction of a turn is required to get from 125 to 150. I'm guessing I turned them, while hot, approximately 3-4x that amount and still not feeling like 150lb-ft, so you can see why I decided to stop and think about what was happening before checking the other nuts and rotating.

So, what's the deal here, and what is a guy to set the torque wrench to when dealing with hot parts?

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[General Geoff]

Is there any sort of anti seize or lubricant on the threads?

 

[Caballus]

I was going round and round clockwise pushing the tires to their limit over a dozen runs and obviously getting more wear on the left front than the right front. My intent was to rotate the tires every few runs, but I noticed something that made me pause.

They're always torqued to 150lb-ft as usual and doublechecked before first run. After 3 runs I went to check the torque on one of rear's lugs before swapping, and it wanted to turn a significant amount before getting close to 150. Checked one of the fronts, got the same. I assumed at that point that the lugs, nuts, and wheels are all more pliable with extreme heat in them. Not wanting to set them to the cold equivalent of somewhere between 200-300lb-ft and snap a lug off, I left everything else alone and abandoned the idea of rotating for the day in order to first ask here what the deal is. The next morning (before another full track day) I loosened everything a bit and retorqued to 150 again with everything cold (and completely forgot to rotate the tires at that time )

Note: I usually torque the lug nuts to 125 first and then go back around to take them to 150. If you ever do this, you'll notice the tiniest fraction of a turn is required to get from 125 to 150. I'm guessing I turned them, while hot, approximately 3-4x that amount and still not feeling like 150lb-ft, so you can see why I decided to stop and think about what was happening before checking the other nuts and rotating.

So, what's the deal here, and what is a guy to set the torque wrench to when dealing with hot parts?

OEM wheels?

 

[JAJ]

...So, what's the deal here, and what is a guy to set the torque wrench to when dealing with hot parts?

Torqueing a set of lug nuts to full torque when whole assembly is super hot is a great way to break the studs. Thing is, pro teams change tires on pit stops, so there must be a setting that works, but I've never seen anything written about it.

 

[oldbmwfan]

How long between sessions? If you have a half-hour, it can cool enough to torque. Just put the car on stands as soon as the session ends, pull the wheels/tires off, and then mount them immediately before going out again. With the wheels off, the hub will shed heat faster. It can also be an end of day or beginning of day thing.

To check torque, it's best loosen at least a couple turns and then re-torque from loose. Putting a torque wrench on a tight lug and then turning it will just increase the stretch, even if it was already "tight enough." And as you're already aware, you don't want to torque them hot.

 

[drummerboy]

OEM wheels?

Signature - forged aluminum.

Torqueing a set of lug nuts to full torque when whole assembly is super hot is a great way to break the studs. Thing is, pro teams change tires on pit stops, so there must be a setting that works, but I've never seen anything written about it.

I'd never even thought about that or heard of it. I left the two that I torqued up where they were for the last 3 sessions knowing that I wouldn't be able to torque them to spec, and then I fixed it the next morning.

Is there any sort of anti seize or lubricant on the threads?

No.

How long between sessions? If you have a half-hour, it can cool enough to torque. Just put the car on stands as soon as the session ends, pull the wheels/tires off, and then mount them immediately before going out again. With the wheels off, the hub will shed heat faster. It can also be an end of day or beginning of day thing.

To check torque, it's best loosen at least a couple turns and then re-torque from loose. Putting a torque wrench on a tight lug and then turning it will just increase the stretch, even if it was already "tight enough." And as you're already aware, you don't want to torque them hot.

Three 30 minute sessions with 30 minutes between
90 minute break
Three 30 minute sessions with 30 minutes between
Repeat next day

I think your plan works out great, and it seems so obvious that I must have just been distracted by the chaos of the day. At the beginning of the 90 minute break, take off all the wheels. Everything can then cool for over an hour and be fine I would imagine.

 

[Caballus]

@50 Deep @honeybadger @Epiphany ...thoughts?

 

[Epiphany]

So, what's the deal here, and what is a guy to set the torque wrench to when dealing with hot parts?

JAJ and BMWfan are dead on, correct.

Bottom line, never torque when hot. Yes race teams do it. They also break studs (as mentioned) and change hardware after 1 race - or pay the piper the next race when they see a failure.

If any of the wheel/brake hardware is too hot to hold and handle with your bare hands, it is too hot to use to attain an accurate, consistent, torque figure. Let things cool off, then torque.

 

[honeybadger]

Agree with the above. Also - I’ve never needed to retorque mid day unless I was changing wheels - in which case I follow up the same advice as above and wait until it’s safe enough to touch with a bare hand.


FWIW - I torque my lugs to 130 ft lbs every morning when things are cool. Never had a loose lug nut and ensures things don’t get over torqued.

Edit. Should note with my method above - I’ve tested it mid day to see if things come loose and they never did. So now I just do mornings or when changing wheels.

 

[JAJ]

... So now I just do mornings or when changing wheels.

Yup, me too. Once in the morning before the first session and it's done for the day.

 

[ShatterPoints]

Agree with the above. Also - I’ve never needed to retorque mid day unless I was changing wheels - in which case I follow up the same advice as above and wait until it’s safe enough to touch with a bare hand.


FWIW - I torque my lugs to 130 ft lbs every morning when things are cool. Never had a loose lug nut and ensures things don’t get over torqued.

Edit. Should note with my method above - I’ve tested it mid day to see if things come loose and they never did. So now I just do mornings or when changing wheels.

I also torque to 130 ft lbs and have not had an issue either street driving or track driving.

 

[drummerboy]

Roger that, thanks guys.

One thing I forgot to add was that the next day I did want to know what the 'hot torque' was, so starting at 90lb-ft and worked up my way up. It doesn't really matter since it is temperature dependent, but if I recall correctly it was like 115ish when they could start to turn. Ford states 150 +/- 10%, so I imagine that if a guy were desperate, he could test this out on his own car and torque them accordingly and at least be close enough. And considering the posts above about 130 being ok, it sounds like we've got a very large window to work with.

That said, I'm sure Kevin's get waaaay hotter at COTA than mine at Chuckwalla and his torque wrench would probably say 85ish.

It was remarkable how 'squishy' they felt when hot.

 

[50 Deep]

In general the wheel itself should not dictate the torque rating. This is all bout the proper amount of pre-load needed between the lug nut and stud.

This is one of the reasons I really like our titanium lug nuts since they are more resielent to swelling under heat. OEM lug nuts are notorious for swelling up and becoming malleable. I would get a better lug nut if you plan to continue with swapping things around. Gorilla makes a fairly good setup that I have not seen fail yet. My titanium ones are legit, but definitely more pricey.

 

[galaxy]

I’m guessing most (this is my reasoning anyways) use 130 is not because they think it’s good enough, or that 150 is too much, but it’s because of the anti seize (or other lube) on the threads. As a general rule, reduce torque around that 10-15% point for lubed threads. So 130 with wet threads theoretically puts you back to that 150 mark.

 

[drummerboy]

In general the wheel itself should not dictate the torque rating. This is all bout the proper amount of pre-load needed between the lug nut and stud.

This is one of the reasons I really like our titanium lug nuts since they are more resielent to swelling under heat. OEM lug nuts are notorious for swelling up and becoming malleable. I would get a better lug nut if you plan to continue with swapping things around. Gorilla makes a fairly good setup that I have not seen fail yet. My titanium ones are legit, but definitely more pricey.

Good point, thanks. I have a set of Gorillas, but they, ordered by accident, are all the locking type. I just had to lol at the track due to the immense PITA. So I was using the factory nuts on this last outing. And come to think of it, I'm almost certain I periodically checked the torque on those Gorillas. If I did, then I surely didn't notice anything amiss, and that would suggest that is in fact the nuts themselves.

Thanks Terrance, I'm going to check the torque on the next outing with good nuts.

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