[arpad_m]

Originally Posted by CC2018SS1LE

That’s crazy, I’ve done a bunch of track days torquing my wheels to 100lbs. Never had a problem, one track I hit 142 Mph. I checked after each session, the wheels never lost torque. I’ve raced cars for years, 140 is really tight, I never heard of torque specs that high

The owner's manual is unequivocal, the wheel nut torque spec is 140 lb-ft and hasn't changed since 2016. When it comes to lug nuts (or brakes), I don't want to go by feel or anecdotal evidence.

[Silent_H_]

LOL how is this even a discussion? Just because your wheels haven't fallen off doesn't mean they won't. I hope you all continue to have good luck, but why in the hell would GM just make up a random number for the torque spec?

I'm bored/excited waiting for my Camaro to be built so I read the manual, and the 2021 also says 140 lb ft (no call-outs for different trims/models either, just like the image above).

[JG61354]

I’ll tell you having also been a racer I was pretty shocked when the manual said 140#’s. The highest I ever torqued the race cars was 115#. I never had a problem. I went ahead and torqued to 140# - what a mistake. It took me standing(jumping)on a 24” cheater to break them loose. Plus killed 6 or 7 of the stock lug nuts. Have since torqued them to 110# and have had zero trouble. Just my two cent’s.

[Stephen12ZL1]

Originally Posted by JG61354

I’ll tell you having also been a racer I was pretty shocked when the manual said 140#’s. The highest I ever torqued the race cars was 115#. I never had a problem. I went ahead and torqued to 140# - what a mistake. It took me standing(jumping)on a 24” cheater to break them loose. Plus killed 6 or 7 of the stock lug nuts. Have since torqued them to 110# and have had zero trouble. Just my two cent’s.

125# feels right to me...140# feels destructive and somewhat galls the threads/lugs.

[Msquared]

Holy shit, people! The torque spec isn't open to interpretation! These studs are 14mm, much bigger than what most cars use...probably because these cars are heavy. A Mustang GT has the same M14x1.5 studs, and Ford calls for 150lb/ft. So it's not like Chevy is out on a limb here. A 14mm stud has a well established torque spec, and 140lb/ft is it. The spec is zip to do with any other factor.

Just because you're "a racer" and never used this high a torque spec before doesn't mean you shouldn't now. You probably never had a car with 14mm studs before. If someone is breaking lug nuts on 14mm studs and thinks they torqued it to 140lb, then either their torque wrench is really off or the studs had previous damage of some sort. If you need a long breaker bar have to stand on the end of it to break loose these lug nuts, then you had considerably more than 140lb/ft on them.

It's your car and you can do what you want, but please stop advising others to torque their lug nuts to less than the factory spec! That's just irresponsible.

[Thill444]

My Gt350 was 150ftlbs, I never had an issue taking the wheels on or off. I really don’t see the problem with 140.

[Whitespeed]

Originally Posted by Msquared

Holy shit, people! The torque spec isn't open to interpretation! These studs are 14mm, much bigger than what most cars use...probably because these cars are heavy. A Mustang GT has the same M14x1.5 studs, and Ford calls for 150lb/ft. So it's not like Chevy is out on a limb here. A 14mm stud has a well established torque spec, and 140lb/ft is it. The spec is zip to do with any other factor.

Just because you're "a racer" and never used this high a torque spec before doesn't mean you shouldn't now. You probably never had a car with 14mm studs before. If someone is breaking lug nuts on 14mm studs and thinks they torqued it to 140lb, then either their torque wrench is really off or the studs had previous damage of some sort. If you need a long breaker bar have to stand on the end of it to break loose these lug nuts, then you had considerably more than 140lb/ft on them.

It's your car and you can do what you want, but please stop advising others to torque their lug nuts to less than the factory spec! That's just irresponsible.

100% agree!!! This is not debatable.


Nigel

[DaveC113]

Originally Posted by Msquared

Holy shit, people! The torque spec isn't open to interpretation! These studs are 14mm, much bigger than what most cars use...probably because these cars are heavy. A Mustang GT has the same M14x1.5 studs, and Ford calls for 150lb/ft. So it's not like Chevy is out on a limb here. A 14mm stud has a well established torque spec, and 140lb/ft is it. The spec is zip to do with any other factor.

Just because you're "a racer" and never used this high a torque spec before doesn't mean you shouldn't now. You probably never had a car with 14mm studs before. If someone is breaking lug nuts on 14mm studs and thinks they torqued it to 140lb, then either their torque wrench is really off or the studs had previous damage of some sort. If you need a long breaker bar have to stand on the end of it to break loose these lug nuts, then you had considerably more than 140lb/ft on them.

It's your car and you can do what you want, but please stop advising others to torque their lug nuts to less than the factory spec! That's just irresponsible.

+1...

[2SS Capt]

This thread should have been exactly 2 posts long, post 1 someone asking what the lugnut torque is and post 2 an image of the owners manual showing 140 ft/lb...

Done...

[Msquared]

Originally Posted by Msquared

These studs are 14mm, much bigger than what most cars use...probably because these cars are heavy. A Mustang GT has the same M14x1.5 studs, and Ford calls for 150lb/ft. So it's not like Chevy is out on a limb here. A 14mm stud has a well established torque spec, and 140lb/ft is it.

I'd like to expand on this a bit. Our cars are heavy and also generate some serious lateral and longitudinal acceleration forces. So the forces trying to spin the wheels on the hub faces are big. This goes for the Mustang and Charger as well. The friction between the wheel and hub is the only thing that keeps it in place, and that friction is provide by the Cf of the hub-and-wheel interface and the clamping force provided by the lug nuts. All three manufacturers clearly decided it is important to have a lot more friction force on these heavy and high-G vehicles, and therefore they spec'd 14mm studs to allow the safe application of extra clamping force compared to a 12mm stud.

So the entire reason for the bigger studs is to allow greater clamping force between the wheel and hub face. If you decide your car is fine with 100lb/ft because you know better than the engineers, you're choosing to reduce the force holding your wheel in place by 29%.

[enzia35]

Oof, gotta buy a $100 tq wrench just to tighten the lug nuts on the Camaro.

[JG61354]

Originally Posted by Msquared

Holy shit, people! The torque spec isn't open to interpretation! These studs are 14mm, much bigger than what most cars use...probably because these cars are heavy. A Mustang GT has the same M14x1.5 studs, and Ford calls for 150lb/ft. So it's not like Chevy is out on a limb here. A 14mm stud has a well established torque spec, and 140lb/ft is it. The spec is zip to do with any other factor.

Just because you're "a racer" and never used this high a torque spec before doesn't mean you shouldn't now. You probably never had a car with 14mm studs before. If someone is breaking lug nuts on 14mm studs and thinks they torqued it to 140lb, then either their torque wrench is really off or the studs had previous damage of some sort. If you need a long breaker bar have to stand on the end of it to break loose these lug nuts, then you had considerably more than 140lb/ft on them.

It's your car and you can do what you want, but please stop advising others to torque their lug nuts to less than the factory spec! That's just irresponsible.

Just to be clear I suggested or advised nothing. I simply stated my experience. I probably have 2500+ laps going around Sebring, Homestead, Road Atlanta in Mustangs, Corvettes and Camaros. I don’t have a $100 Nothern freight torque wrench. I take a little exception to the idea I’m suggesting anything. You certainly may do it anyway you see fit, no argument from me. Maybe we can hook up some where and run some laps in your part of the world. At any rate stay safe.

[Msquared]

Originally Posted by JG61354

Just to be clear I suggested or advised nothing. I simply stated my experience. I probably have 2500+ laps going around Sebring, Homestead, Road Atlanta in Mustangs, Corvettes and Camaros. I don’t have a $100 Nothern freight torque wrench. I take a little exception to the idea I’m suggesting anything. You certainly may do it anyway you see fit, no argument from me. Maybe we can hook up some where and run some laps in your part of the world. At any rate stay safe.

You asserted "racer" experience as a way to lend credibility to your claims that you torqued your lug nuts to 140lbs and you had had to jump on a two-foot breaker bar to get them loose, you ruined a bunch of lug nuts, and you're using 110lb/ft now with no trouble. Do you honestly think that's not a persuasive statement? BTW, the number of laps you have driven is a non sequitur to this topic: the wheels, studs, and lug nuts don't care about your tack resume.

But since you want to argue the point, let's dissect your post a little further. You torqued them to 140lb/ft, but you don't have a suitable torque "northern freight" torque wrench, so...how do you know what you torqued them to? For someone wanting to assert his racing credentials, it seems awfully strange that you don't have a cheap torque wrench to tighten your lug nuts properly. It's a little like a mechanic saying it's okay to work underneath your car without jackstands because he can't afford them. By the way, you can buy an adequate torque wrench from Autozone for $47. I don't think it's news to anyone that you need the proper tools if you want to work on your car yourself. But to put this in perspective, a proper oil/filter change on our cars costs around $100 if you do it yourself (just the oil and filter, not including tools).

You stated you had to jump on a 24" breaker bar to get them loose at 140lb/ft. So...you only weigh 70lbs? Because that's the force we're talking about at the end of a two-foot lever to reach 140lb/ft. And you ruined the lug nuts doing so? This despite the fact that millions of cars and trucks these days have 14mm studs and similar torque requirements, and other people aren't complaining about similar experiences? A modicum of thought from someone who's touting a road racing resume should tell you those things don't add up. It seems way more likely that your lug nuts were torqued to a force much, much higher than the specified 140lb/ft, or they rusted on, or something like that. Whatever problems you had, they weren't the result of torquing to the factory spec.

Stay safe, indeed.

[Scargoes]

People do what they want, but there is a reason the spec is 140lbft. It's not out of line either. Ford is 150, Tesla is 135. At least you aren't having to torque my truck wheels, 450-500lbft.