Shearing off wheel studs

[pcinpdx]

Has anybody had problems with shearing off the rear wheel studs on their cars? All five studs sheared off of the left side when I was at the drags on Friday night and then the other five sheared off of the right side today while I was driving downtown. On Friday I could see why - I was getting a little wheel hop under full power off of the line. Today, on the other hand, I was getting on it a bit but nothing too insane. Just a blip on the throttle to break the tires loose is all that it took - no wheel hop, no sideways action just going in a straight line and BAM! the car was on the ground with my tire passing me by.

The first question I'm sure that most will ask is if these were stock studs. The answer is no. They were the studs installed by Moser when I bought the axles less than a year ago.

My question is have any of you guys seen this kind of thing? I'm wondering if I got a bad batch of wheel studs from Moser and if I have any kind of recourse on the esuing expenses I've had to shell out for getting things squared away - namely the towing bill.

 

[strtracer442]

What type of wheels are you using,what type of lug nuts , and what size were the wheel studs? More than likely,you damaged both sides earlier than when they actually broke. If the rim hole doesnt fit snugly around the studs,or you're using universal fit rims,thats the problem. Post up some pics and we might be able to figure it out. I seriously doubt that you have any recourse against Moser unless YOU can PROVE the studs are defective.

 

[pcinpdx]

I've got the Cobra rims from a '96 on it. I'll post some pics tonight of the rims and of the studs.

 

[NKau]

You run slicks on your car? I still find that pretty odd; you don't usually hear of that happening except in pretty high HP cars.

 

[89MustangGX]

It's awful strange that you'd lose ALL of them, not just on one wheel, but both??? Something is definitely up. I'd collect all the pieces of the studs if you can and hang on to them while you figure out what happened.

 

[pcinpdx]

Sorry I haven't posted pics yet but I found out that my camera was at my house when I was at my shop (about 30 miles away). I've got the camera and I'll see if I can't get some pics posted tomorrow.

One thing I did find is that the center hole on the rim does not line up with the center of the axle. I called Moser about this and told them what I found but was told that it didn't matter. I told them that there was about a 1/8" space between the axle backing where the rim met the axle but the person I talked to said again that it didn't matter. I told him that it seems that the wheel would then travel in an elliptical pattern. Again, he said that it doesn't matter. I also asked if there is any way that the holes could have been drilled incorrectly to which he simply stated "No." He told me repetedly that there were only three ways a stud would break:

1. The nuts were over-torqued on the studs
2. The nuts were under-torqued on the studs
3. There is too much hp for the studs to withstand.

I asked what they recommend for a torque value on the studs and was told 25 ft-lbs. To me this sould extremely low.

It sounds like to me. I think I'm getting the runaround from these yahoos but I'd like some tech to back it up. If I'm right then I'd like them to rectify the situation. If I'm wrong, I'd like some tech to back it up.

You run slicks on your car? I still find that pretty odd; you don't usually hear of that happening except in pretty high HP cars.

No slicks but I am running DRs. While I haven't dynoed the car, I should be somewhere in the neighborhood of 400 rwhp which, I don't feel is dramatic enough to cause this type of issue.

 

[ECU5.0]

25 lbs of torque is way too low....and the thing about the center of the rim and axle....you saying the rim doesnt sit flush against the hub....or the center of the axle is 1/8 in off from the center of the wheel? because either one would cause some bad consequences

 

[89MustangGX]

The rims not sitting right is definitely the problem. You do not have enough traction or power to break those studs, and I think it would take a pretty hefty guy to overtorque them THAT much. Undertroquing is one thing, but you'd fel whe wheel wobble before they just broke off.