[marshall834]

Recently getting new tires, I had a local body shop install and balance them as I've had experience with them in the past and they're very reasonably priced.

Today I went to work on the car and noticed my impact wrench was having a hell of a time taking the lug nuts out. I finally grabbed my breaker bar and got them loose that way.

After taking that tire off, I used my torque wrench to see what the exact settings were. Most bolts I tested were 145+ (BMW specs @ 90)

My question is, does this do any damage to the nut or the wheel itself? I drove like this for nearly two weeks before noticing. I've re-torqued since.

[alexwhittemore]

Originally Posted by marshall834

Recently getting new tires, I had a local body shop install and balance them as I've had experience with them in the past and they're very reasonably priced.

Today I went to work on the car and noticed my impact wrench was having a hell of a time taking the lug nuts out. I finally grabbed my breaker bar and got them loose that way.

After taking that tire off, I used my torque wrench to see what the exact settings were. Most bolts I tested were 145+ (BMW specs @ 90)

My question is, does this do any damage to the nut or the wheel itself? I drove like this for nearly two weeks before noticing. I've re-torqued since.

Damage, no. Wheel nuts and bolts are designed to absurd tolerances, maybe -10%+250%. Maybe even + more.

It's a pain in the ass though. I had a nut torqued so tight when I first bought the car that I broke like 4 tools trying to get it off, then broke the wrench I WELDED to the nut. I had to grind the weld down flat then drill it out with a cobalt bit (the bolt blunted a regular bit) in a hammer drill with heaps of fluid. It was a nightmare.

[zipstic]

If the lugs are torqued too tight it can cause warping of the rotors.

[jphughan]

Not sure if the wheels were damaged, but you might have damaged your torque wrench. It's well-known and mentioned in many torque wrench manuals that you shouldn't use them to loosen bolts.

[Xpander]

Damn I would think that much torque would strip the threads. I start freaking out when I'm 10 ft-lbs over.

[galahad05]

Yeah, I finally bought myself a breaker bar last year (and a new set of bolts) when I ended up having to try all kinds of stuff to take off the passenger side front wheel. Dealership had waaaay overtorqued it. Ended up rounding the bolt heads too.

[Kalidian]

Originally Posted by galahad05

Yeah, I finally bought myself a breaker bar last year (and a new set of bolts) when I ended up having to try all kinds of stuff to take off the passenger side front wheel. Dealership had waaaay overtorqued it. Ended up rounding the bolt heads too.

Because dealers like to save time by cutting corners, using an impact wrench to bolt wheels on rather than a torque wrench to proper settings.

[scheherazade]

When it sits for a while, it will 'age in', and be tougher to remove than when it was first tightened.

Maybe not 150, but 110 or so is not a surprise if it was initially tightened at 80.

-scheherazade

[marshall834]

Originally Posted by jphughan

Not sure if the wheels were damaged, but you might have damaged your torque wrench. It's well-known and mentioned in many torque wrench manuals that you shouldn't use them to loosen bolts.

Nah I didn't use the torque wrench to loosen, used my breaker bar. I inspected some nuts and they looked fine.

I have an appointment for an alignment next week we'll see what they say.

[alexwhittemore]

Originally Posted by zipstic

If the lugs are torqued too tight it can cause warping of the rotors.

That's pretty much just straight up a myth. For one, consider the wheel-rotor interface. The bolt ring on the wheel is a flat plane that mates up with a flat plane on the rotor hat. You can overtorque an individual bolt all you want - it's not going to warp the steel. There's nowhere for the steel to even yield to - you'll strip the threads way before then.

Beyond that, rotor 'warp' is virtually always uneven deposition of brake pad material onto the rotor surface rather than actual deflection of the rotor. Think about it. Even if you were to heat the rotor to the point of yielding (which you never do), the brake pads pull the rotor in an exclusively torsional direction, there would be no deflection parallel to the axle anyway.

Anyway, that's neither here nor there. Unevenly torquing your wheel lugs stands to cause much more damage than OVERtorquing one. For example, if you put the wheel on and torque one bolt down to 150lbs, you could easily bend the flange that holds the wheel.

But then that's exactly what most shops do anyway, so even that's probably quite unlikely.

EDIT: Point of data to back this: my wheels were all egregiously over-torqued when I bought the car, and remained so for a good 7-8 months, during which I heated the brakes aggressively, panic stopped, etc etc etc more than once. Most bolts were, by my calculated estimation, 150lbs or so. One was comfortably over 250-300lbs. Surely, that wildly uneven torque would indicate a prime candidacy for rotor warp, which I have never experienced on this car.

[Hybrid For Life]

Originally Posted by jphughan

Not sure if the wheels were damaged, but you might have damaged your torque wrench. It's well-known and mentioned in many torque wrench manuals that you shouldn't use them to loosen bolts.

He said he used a breaker bar to loosen them, he check the torque with a torque wrench

[John 070]

Originally Posted by jphughan

Not sure if the wheels were damaged, but you might have damaged your torque wrench. It's well-known and mentioned in many torque wrench manuals that you shouldn't use them to loosen bolts.

I had a Craftsman torque wrench that was from the 90's. My wife's car was spec'd to 140 lbs. ft from the factory, so when I cranked my torque wrench up to 140 and used it, it broke.

When I used my current torque wrench to that spec, it was fine.

imho many people don't realize that a torque wrench is less accurate at its low end. for example, you often have a choice of 30 to 250 or 20 to 150 in a 1/2". So if you're going to do a lot at say 45 lbs., you better choose the 20 to 150, because the 30 to 250 is not accurate below 50.

imho #2, shops cannot rely upon customers to recheck/tighten lugs after they've left, so they have to overtighten for liability. I've never had a BMW dealership tell me to make sure I recheck my lug nuts 3X after they've removed my wheels.

[Efthreeoh]

Originally Posted by marshall834

Nah I didn't use the torque wrench to loosen, used my breaker bar. I inspected some nuts and they looked fine.

I have an appointment for an alignment next week we'll see what they say.

I'm still confused as to how you used a torque wrench to determine what the torque was applied to the wheel bolts. Did you re-tighten the wheel bolts and the re-loosen them with the breaker bar again? That would not give you an accurate measurement if you were using "muscle feel" to determine the required force to loosen the bolt.

That said, I don't think any damage was caused. I had a BMW dealer over-torque a wheel bolt on my right rear wheel so hard it broke my 17MM Craftsman impact socket when I went to rotate the tires a few weeks later. I have a Ingersoll 2131 impact gun with 1,000 ft.lb. reverse torque. I didn't find any damage to the bolt, wheel, or hub.

Also, the torque applied to properly tighten down the bolt (88 ft.lb. for BMWs) is not related to the torque necessary to remove it. What theoretically could have happened is the bolt was over stretched and could fail at some other time, or the bolt hole in the wheel could have been cracked from overstress. However, the size of and material of the bolt is far more capable of taking just 88 ft.lb. of torque. The conical shape of the bolt hole face allows for a much greater application of force before the material would start to spread and crack. Like another Poster said, there is no place for the material to spread.

Finally, you need to understand the engineering. The wheel bolts are designed for a safety factor of 4, meaning they can take 4 times greater stress than the application they are used for. This is standard engineering practice. The reason the torque is only 88 ft. lb. (which is not a lot by the way for the size of the wheel bolt) is to (traditionally) allow for hand removal of the bolts on the road side to remove the wheel and replace it with a spare.

[John 070]

Originally Posted by Efthreeoh

I'm still confused as to how you used a torque wrench to determine what the torque was applied to the wheel bolts.

Agreed, I could see that if he tried to tighten with his wrench at 150, and it clicked right away, that would imply that the lugs are 150+, +/- 4% or so...

[Efthreeoh]

Originally Posted by John 070

Agreed, I could see that if he tried to tighten with his wrench at 150, and it clicked right away, that would imply that the lugs are 150+, +/- 4% or so...

Here's the thing I have an issue with, which is wheel bolts loosening in the first 500 miles and require re-torqueing. I've never experienced this, ever. I think it is a myth.

[J02 335i]

Its rare but Ive seen it happen, drastic temperature change affects metals differently, steel bolts and aluminum wheels. Thats why its only recommend with aluminium wheels.

Its also a liability thing for shops.

[marshall834]

Originally Posted by John 070

Agreed, I could see that if he tried to tighten with his wrench at 150, and it clicked right away, that would imply that the lugs are 150+, +/- 4% or so...

This is exactly what I did. I started at 90 and went up in 10 lb increments and the torque wrench clicked immediately at every single interval. Some nuts stopped clicking ~135 (as the bolt moved before it clicked) but in most cases I put the wrench on and it clicked immediately.

I get the bolt being manufactured to certain standards it's the wheel surface I'm concerned about - any hairline cracks, etc. But this has been all good information, thanks!

[marshall834]

Originally Posted by Efthreeoh

Also, the torque applied to properly tighten down the bolt (88 ft.lb. for BMWs) is not related to the torque necessary to remove it.

Can you explain this more? If I went to re-tighten the bolts with the wrench, this is not removing the bolt but rather tightening it, giving me an accurate reading.

[zipstic]

Originally Posted by alexwhittemore

That's pretty much just straight up a myth. For one, consider the wheel-rotor interface. The bolt ring on the wheel is a flat plane that mates up with a flat plane on the rotor hat. You can overtorque an individual bolt all you want - it's not going to warp the steel. There's nowhere for the steel to even yield to - you'll strip the threads way before then.

Beyond that, rotor 'warp' is virtually always uneven deposition of brake pad material onto the rotor surface rather than actual deflection of the rotor. Think about it. Even if you were to heat the rotor to the point of yielding (which you never do), the brake pads pull the rotor in an exclusively torsional direction, there would be no deflection parallel to the axle anyway.

Anyway, that's neither here nor there. Unevenly torquing your wheel lugs stands to cause much more damage than OVERtorquing one. For example, if you put the wheel on and torque one bolt down to 150lbs, you could easily bend the flange that holds the wheel.

But then that's exactly what most shops do anyway, so even that's probably quite unlikely.

EDIT: Point of data to back this: my wheels were all egregiously over-torqued when I bought the car, and remained so for a good 7-8 months, during which I heated the brakes aggressively, panic stopped, etc etc etc more than once. Most bolts were, by my calculated estimation, 150lbs or so. One was comfortably over 250-300lbs. Surely, that wildly uneven torque would indicate a prime candidacy for rotor warp, which I have never experienced on this car.

Good to know. There's a lot of talk about it causing issues, but like you said maybe it's just a myth at this point. It sounds like you know a lot about the topic

[alexwhittemore]

Originally Posted by Efthreeoh

Finally, you need to understand the engineering. The wheel bolts are designed for a safety factor of 4, meaning they can take 4 times greater stress than the application they are used for.

I've always wondered what the actual factor is, where'd you get 4?

[alexwhittemore]

Originally Posted by marshall834

Can you explain this more? If I went to re-tighten the bolts with the wrench, this is not removing the bolt but rather tightening it, giving me an accurate reading.

I think saying they're 'unrelated' is a stretch, but certainly saying 'they're not necessarily the same' is accurate.

When you torque a bolt, the force goes to two functions. 1) it tensions the bolt axially, loading the threads. 2) it contributes to friction between the head and whatever work you're bolting down (in this case the wheel).

Imagine two setups, one where the bolt-wheel interface has zero friction and one where it has infinite friction.

In the first case, all the torque loads the threads. There's no friction on the bolt head, so there's nothing to impede torquing the bolt further besides the thread loading. Unfortunately, only the friction in the threads will hold the bolt from unscrewing.

In the second case, as SOON as the bolt head touches the wheel, you can't turn the bolt any further. Any and all torque applied is fighting that friction, and the threads don't get loaded whatsoever.

Neither can actually happen, of course, but the former is like when you apply lube to the bolt, and the latter is more like normal operation. This is one reason manufactures virtually always recommend AGAINST using lube on wheel bolts - for the same applied torque, the thread loading and tension is higher, and simultaneously the bolt is more likely to rattle or thermal cycle itself loose. If you torque to the same spec, you're closer to damaging the bolt and it's also closer to falling out on its own.

Anyway, the friction in the head is the same reason that torque in isn't always the same as torque out - imagine the infinite friction example. You could torque the bolt to 1000ft-lbs and it'd never move, thus no thread loading. But because there's infinite friction, it'd be JUST ON THE EDGE of falling out on its own - if you measured the torque to get it out, it'd be very low. Much much lower than 1000ft-lbs.

Of course, this is a far more linear, idealized model of the head 'catching' than actually happens. Which is why most torque specs, if you're getting really serious, say something like "torque to 88 ft-lbs, then another 30 degrees of turn"


As far as the wheel falling off on its own: it's not a myth, it definitely happens. But it IS quite rare. Personally, I've been torquing my wheels on whenever I've had to get them off, always driving 100mi then re-torquing. I've never noticed any additional bolt turn when I did, suggesting that the wheels were fully settled in when I originally torqued them down.

That said, I've also had friends who failed to go back to the shop after 100mi for retorquing and had wheels fall off on the highway.

I think the reason that's super rare, though, is that most shops just torque them down so hard there's no chance they'll settle so far as to come loose.

[jphughan]

Originally Posted by Hybrid For Life

He said he used a breaker bar to loosen them, he check the torque with a torque wrench

Ease up there dude, the OP said he used a breaker bar to loosen ONE of the wheels and then checked the torque with a torque wrench. I read that as the OP possibly having just set the torque wrench higher and higher until it loosened a bolt rather than clicking over, but fortunately it looks like that wasn't what happened.