Jcpstrat

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For those of you who run spacers with your wheels make sure the lug-nuts engage the proper amount of threads on the wheel studs.

I came VERY close to loosing the passenger side rear wheel recently. I was about to attend a local Cars & Coffee event but when I backed my Vette out of the garage I heard an odd sound from the rear. As I pulled it back into the garage I heard that same sound. I looked under the car at the rear suspension and nothing looked obviously wrong. I decided not to drive it but as I was closing the garage door I noticed something shiny on the drive way. I found 2 lug-nuts (first pic), each with the wheel studs sheared off. I started walking around my car and found the rear passenger side wheel only had 1 lug-nut left (2nd pic), and 4 studs missing. I torqued all 4 wheels myself with my torque wrench to 75 ft-lbs (67 factory spec), when I installed them. This happened with approx. 1,000 of miles on the wheels.

Lugnut/stud pic
Wheel Studs.jpg


Wheel pic
PassSideRearWheel.jpg


It took me a while to figure out what caused the problem. The (4) wheel studs were sheared off flush with the spindle outer surface. The cause was shear stress caused by the lug-nuts only engaging about ¼” of wheel stud threads due to the ¼” spacers I installed.

The tire/wheel/lug-nut vendor I used, ASME and NHRA all recommend that lug nuts should engage a minimum length of threads equal to the diameter of stud. In my case 7/16".
The vendor I purchased my wheels/tires/lug-nuts from near the end of 2018, while body was still off the frame, acknowledged that when they sent me spacers, to cure a wheel/caliper interference issue, they should have also sent me Extended Thread MAG E/T Tapered lug-nuts & locks to replace the ones they had originally sent with the wheels/tires.

Figuring that all the wheel studs have been stressed I've replaced them all. Just a heads up for anyone else running or thinking about running spacers.
 

Rruuff Day

Never wrestle with a pig.
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For those of you who run spacers with your wheels make sure the lug-nuts engage the proper amount of threads on the wheel studs.

I came VERY close to loosing the passenger side rear wheel recently. I was about to attend a local Cars & Coffee event but when I backed my Vette out of the garage I heard an odd sound from the rear. As I pulled it back into the garage I heard that same sound. I looked under the car at the rear suspension and nothing looked obviously wrong. I decided not to drive it but as I was closing the garage door I noticed something shiny on the drive way. I found 2 lug-nuts (first pic), each with the wheel studs sheared off. I started walking around my car and found the rear passenger side wheel only had 1 lug-nut left (2nd pic), and 4 studs missing. I torqued all 4 wheels myself with my torque wrench to 75 ft-lbs (67 factory spec), when I installed them. This happened with approx. 1,000 of miles on the wheels.

Lugnut/stud pic
View attachment 44871

Wheel pic
View attachment 44872

It took me a while to figure out what caused the problem. The (4) wheel studs were sheared off flush with the spindle outer surface. The cause was shear stress caused by the lug-nuts only engaging about ¼” of wheel stud threads due to the ¼” spacers I installed.

The tire/wheel/lug-nut vendor I used, ASME and NHRA all recommend that lug nuts should engage a minimum length of threads equal to the diameter of stud. In my case 7/16".
The vendor I purchased my wheels/tires/lug-nuts from near the end of 2018, while body was still off the frame, acknowledged that when they sent me spacers, to cure a wheel/caliper interference issue, they should have also sent me Extended Thread MAG E/T Tapered lug-nuts & locks to replace the ones they had originally sent with the wheels/tires.

Figuring that all the wheel studs have been stressed I've replaced them all. Just a heads up for anyone else running or thinking about running spacers.

Wow John. You were very lucky. Your baby (and you) were likely saved a lot of hurt by your good luck and noticing before it became a catastrophe. Glad you caught it before it came to that.
 

Jcpstrat

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Thks Rruuff Day ... I know I was very fortunate in many ways this could have turned out. In the process of trying to figure out what when wrong another Corvette owner of a C3 said he had a wheel come off and it did over $3,000 worth of damage to the body.
 

Rruuff Day

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I can easily see that. Doesn't take much of anything anymore to do a lot of body damage, let alone hub and brake skidding down the asphalt...
 

nascar03

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JOHN..
You are sooooo lucky man.
I’m glad you were aware enough to STOP.
That could do so much damage.
When did the missing two nuts come off??
I’m curious if you removed the nuts from the broken stud(s) to see how much you were grabbing.?

glad you are safe.

graham
 

Jcpstrat

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graham ... I agree about being lucky.

I have no idea when the (2) lug-nuts & studs came out that were totally missing and I did search about a 1/4 mile in either direction from my house. The other (2) just fell out when backing out of the garage. I was unaware of any driving issues when I pulled the car in the garage ... this happened after the car & wheels cooled down.

Yes I checked the lug-nuts and they were only grabbing 1/4" of threads. Interestingly I could take the nuts that came off the broken studs and thread them back on the broken end of the stud with no problem. The threads were not distorted at all where they broke ... a very clean shear.
 

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