Z4m BBS CH lugs overtorqued by 40%...

[Rombbb]

Hello,

For Z4M the advised wheel torque is 88ft/lb's, 120NM, +/- 10% approximately.

BBS CH docs state 82ft/lb's, around 110Nm.

My lugs were torqued at around 115 lb/ft, 155Nm, 40% more.

I guess ft/lb's and Nm's were mixed up during tightening. Thinking it was Nm the wrench was set to 115, but as it was a ft/lb wrench this resulted in 155Nm of torque.

It's corrected now and I checked the lugs on one wheel which looked pretty ok, as far as that can be seen by the naked eye. That alloy wheel did need some persuasion in getting of the hub but that could be normal, don't know.

Happy nothing cracked, the car seemed to drive fine. Was overtorqued for almost a year, not that many miles.

Is all good now or were the lugs stretched too far and I better replace them ?

Thank you

Ps. the idiot that overtorqued them was almost certainly me

 

[Jakg]

How do you know it was over torqued? You normally need more torque to loosen than to tighten, especially if it'd been there for a year.

I wouldn't worry about it personally.

 

[Rombbb]

How do you know it was over torqued? You normally need more torque to loosen than to tighten, especially if it'd been there for a year.

I wouldn't worry about it personally.

Ah cool, learning moment for me. That gives some piece of mind.

But isn't the difference a bit big ? Let's say it was torqued ok at 90 lb-ft can it be that it needs some 110-115 to come loose ?

 

[MrPT]

Even if the bolts are a little stretched they won’t break. Just re-check the torque more regularly for a while and if they’re holding, no worries.

 

[Ed Doe]

Have you seen how most tyre monkeys put wheels back on after a tyre change?! Torque wrench hanging off the back rattling away on each nut - and no one has any issues aside from a lot of swearing when they have to take a wheel off again by hand! Honestly if you've been able to input that torque with a bar it'll be absolutely fine, I really wouldn't worry at all :lol:

 

[PDJ]

I would suggest that wheel bolts/studs are 10.9

 

[JoshsZ4M]

Have you seen how most tyre monkeys put wheels back on after a tyre change?! Torque wrench hanging off the back rattling away on each nut - and no one has any issues aside from a lot of swearing when they have to take a wheel off again by hand! Honestly if you've been able to input that torque with a bar it'll be absolutely fine, I really wouldn't worry at all :lol:

Could not agree more here. Monkeys at QuickFit ripped off my other half a few years ago for tyres she didn’t need, and snapped wheel bolts (Suzuki Alto) in the process!

 

[Rombbb]

I would suggest that wheel bolts/studs are 10.9

Thanks, will check

 

[Rombbb]

Even if the bolts are a little stretched they won’t break. Just re-check the torque more regularly for a while and if they’re holding, no worries.

I will, thanks

What I'm wondering though is when they were stretched and now torqued to spec, i.e. much lower, whether there's enough friction to keep them on or whether you need to keep the overtorqued value because that's what the metal deformed to. Like whether the metals stays stretched or it is like elastic and forms back into spec dimensions.

They did feel sufficiently tight at correct torque of around 90, so am guessing it's indeed all fine.

 

[Rombbb]

Could not agree more here. Monkeys at QuickFit ripped off my other half a few years ago for tires she didn’t need, and snapped wheel bolts (Suzuki Alto) in the process!

Dude at Kwik Fit (high volume tire shop in NL) stuck the balancing weights on my rim on the (out)side of the wheel instead of the inside where the centrifugal forces would keep them in place. I noticed it but otherwise I guess someone pedestrian would have head butted some wheel weights eventually :dizzy:

Dangerous actually how non-skilled and insufficiently trained guys are plucked from the streets and assigned to take care of lots of peoples wheels and tires.