Broken / cracked lugbolts after last Track Day!! pics

[pixelblue]

Originally Posted by HondaGoneRogue

Skinny is (correctly) referring to these. This was on their site:

so that's good to know. thanks! anyways I'll try something different next time. I hear TC Klines make some quality studs

[SkinnyVT]

Originally Posted by HondaGoneRogue

Skinny is (correctly) referring to these. This was on their site:

Originally Posted by pixelblue

so that's good to know. thanks! anyways I'll try something different next time. I hear TC Klines make some quality studs

Yup those are the ones I was talking about, the old silver (zinc) ones. The cheapest ones they sold. Luckily I didn't have any issues with them before I switched to the BW ones. Not sure if BW is going to do a 12 days of christmas sale again this year but that is when I got mine last year at a significant discount.

[pixelblue]

"drives like an asshole" LOL, that's hilarious! that used to be me before I was conformed by the law and insurance companies

[Dackelone]

Originally Posted by DriveHard

Well.... YES..



BTW i did check the official BMW Repair instructions and the correct Torque for the standard M12x1.5 Lug Bolt is 120 Nm

1 newton meter = 0.737562149 foot pounds

120 x .7 = 84 Ft/Lbs
120 x .73 = 87.6 Ft/Lbs
120 x .737 = 88.4 Ft/Lbs

so i guess its safe to say 85 to 90 Ft/Lbs ( or as accurate as you can see the line on the torque wrench

In my "BMW jack and tool kit", there is a preset torque wrench made my HEYCO. It is preset to: 130Nm.

130Nm = 96 Ft/Lbs So... I think it is safe to torque the wheel bolts to 96 Ft/Lbs.

On my old '86 Porsche 944 Turbo (with wheel studs) Porsche's lug nut spec was 120 Ft/Lbs. And the lug nuts were made from titanium - I think. I remember they were VERY light.

[Spec Volcanic]

When I autoX regularly I found there was one thing other then over torqueing the lugs then lead to regularly failure.

Torqueing the wheels when the wheels and lugs were still hot.

After my last run of the day I would also quick rush to change wheels before I had to marshal so I could head straight to pub for a beer with the boys after the event. I would be changing the wheels when the lugs were so hot there were hard to hold... and next time I would try to change the wheels, sure enough I would have to snap / break a lug to get the wheel off...

As soon as I started waiting until the wheels were cool... no more braking lugs every other weekend

[fourtailpipes]

make sure anytime anyone other than yourself touches the car, they hand-torque the lugs. my local dealership routinely installs lugs using many whacks with an impact gun if you don't babysit them. i've measured them coming off, and have gotten results as high as 200+ ft-lbs. that will ruin a set of bolts/studs for sure. in the case when i was seeing 200+, one of the bolts broke coming off as well.

not suggesting user error necissarily, but unless you're the only one who touches your car, you never really know. to be safe, i replace them every spring so i'm not bringing any winter road salt corrosion with me to the track.

[DriveHard]

Originally Posted by Spec Volcanic

When I autoX regularly I found there was one thing other then over torqueing the lugs then lead to regularly failure.

Torqueing the wheels when the wheels and lugs were still hot.

After my last run of the day I would also quick rush to change wheels before I had to marshal so I could head straight to pub for a beer with the boys after the event. I would be changing the wheels when the lugs were so hot there were hard to hold... and next time I would try to change the wheels, sure enough I would have to snap / break a lug to get the wheel off...

As soon as I started waiting until the wheels were cool... no more braking lugs every other weekend

Thanks spec..

Yeah i know better then to crank on hot lugs.. those wheel studs are looking better and better anyway.. im just a little vain and hope that the 75mm long ones look ok in the stock wheels..

[DriveHard]

Originally Posted by fourtailpipes

make sure anytime anyone other than yourself touches the car, they hand-torque the lugs. my local dealership routinely installs lugs using many whacks with an impact gun if you don't babysit them. i've measured them coming off, and have gotten results as high as 200+ ft-lbs. that will ruin a set of bolts/studs for sure. in the case when i was seeing 200+, one of the bolts broke coming off as well.

not suggesting user error necissarily, but unless you're the only one who touches your car, you never really know. to be safe, i replace them every spring so i'm not bringing any winter road salt corrosion with me to the track.

Ill be honest... its me 100% of the time...i do use my electric impact to help get them on every wheel swap, but i dont use that as a tightening tool just to get them on enough to be flat against the hub.. then out comes the torque wrench.. It appears all this time i think i have been going 5 to 10 lbs to tight.. live and learn..

In any case new lugbolts on there till next season..then ill decide on the studs..maybe ill catch a sale or something..

Thanks again for everyones input..

[Xaeryan]

You can also try a torque stick (Google it) for your impact gun. I have used one, and verified calibration - they work and they're pretty inexpensive.



I'm surprised more shops don't use these - they're still cranking my lugs to 200 lb/ft.

[satakal]

thanks for the good info guys.

[bogart]

90-100 ft-lbs is way too much and yes bolts have a life cycle. It was probably a mixture of torquing the bolts multiple times and using too much torque. It is also important to torque in stages when torquing a bolt to such a high value. Time for studs.