wheels studs breaking repeatedly - a real puzzler

[ckissick]

I bought larger wheels and tires for my 4WD Vanagon (the Tristar). Spacers were required for them to fit. I bought a set of 4 spacers, each with studs attached. So I first install the spacer using the original studs, then bolt the wheel onto the spacer with the new studs that are attached to the spacers. You get the idea.

The new studs that are attached to the spacer keep breaking. I have broken 9 so far. Fortunately, the wheel has not fallen off while driving. But I have driven home only to discover just 2 of 5 studs remaining on the wheel. That's when I put the old tires on without the spacers and get new studs installed.

Here's the thing. They always break on the same wheel: the left-front (driver side). The brake disc appears to be true, the spacer has been measured and is true, and the wheel appears to be true.

If they broke on different wheels, I would just attribute it to weak metal. But it's always the same wheel.

Note that the car is 4WD with a viscous coupler, meaning there is always some power to the front wheels.

Any ideas on what's going on? Also, can anyone recommend a clever machinist/tire guy in the SF Bay Area who might be able to solve this puzzler?

[bell]

biggest reason for broken studs is improperly torqued lugs, meaning 2 of the 5 lugs were way tighter than the others......how wide of a spacer? i've done numerous spacers on lifted trucks (some spacers as wide as 4") and never had anything break.....

[Scott R]

Also a dragging brake caliper will cause excessive heat and the studs will snap. But of course torque above all is key.

[ckissick]

I use a torque wrench. Also, the studs always break on the same wheel. 9 out of 9. If it was a torque issue, you'd think some studs would break on other wheels.

[ckissick]

I'll look into the dragging brake caliper. I hadn't noticed it, but that idea does at least focus the problem to one wheel.

[Tishabet]

Your Tristar is cursed. I am willing to sacrifice myself by taking it off your hands....

[ckissick]

Originally Posted by Tishabet

Your Tristar is cursed. I am willing to sacrifice myself by taking it off your hands....

No thanks, but you can pick this one up (Alas, 2WD)

http://www.thesamba.com/vw/classifieds/detail.php?id=670171

[TerryH]

Can you rotate the suspect wheel AND spacer to another corner of the car? If the problem follows, its the wheel/spacer, if it stays it's the car.

[ckissick]

Originally Posted by TerryH

Can you rotate the suspect wheel AND spacer to another corner of the car? If the problem follows, its the wheel/spacer, if it stays it's the car.

I suppose so, but that method entails driving the car waiting for studs to pop. But if they're gonna go anyway... Still I'd like to solve it another way.

[competentone]

Originally Posted by ckissick

I use a torque wrench. Also, the studs always break on the same wheel. 9 out of 9. If it was a torque issue, you'd think some studs would break on other wheels.

When the first one broke, did you replace all five studs in the spacer? If not, maybe you are just dealing with "one problem" of defective studs originally installed on the spacer.

Let's say you had five defective studs originally and one broke. You notice it and replace the one broken stud. Now, if one of the remaining four defective studs break, it would put excessive stress on the other studs, quite possibly the "new" stud you had just replaced. The second stud breaking, could stress the "newly replaced" stud, so that it breaks too. If you replace those two, you still would have three defective studs on the spacer. If another of the original spacer studs break, it could again stress the wheel and break another of the newly replaced studs.

My point, you could get up to a total of "9" studs on one wheel needing replacement, because originally four or five of the studs on the spacer were defective and each time one broke it stressed the other studs and ended up breaking some of the other "newly replaced" studs.

The suggestion of shifting the position of the spacers is an option, but since you say "They always break on the same wheel: the left-front (driver side)," I'd still wonder about the stud strength in the spacers even if the same happens when you reposition a spacer to the left-front wheel.

Our roads -- with driving on the "right" side -- results in the most stress on a left front wheel when making right-hand turns. Left turns put stress on the right-front wheel, but our left turns tend to be more "sweeping," so stress on the wheel is lower than on most right-hand turns. If your set of spacers have weak studs on all of them, putting a spacer from another position onto the left-front wheel could result in broken studs, even though there is no problem with the car itself.

Additionally, have you saved the remainder of the broken studs? (I'll assume you don't have the outside broken off portions, as they have probably been thrown some distance and broken someone's windshield as they passed you .) The metal of the remaining portion of stud could be examined to determine if there is a problem with the metal itself.

[gtc]

Just a few thoughts....
1. Compare the bolt circle diameter of the wheel to that of the spacer. Make sure the studs are lining up perfectly with the holes.
2. Make sure you have the right size and shape lug nuts for the wheels

A friend of mine had some trouble with his boat trailer because the previous owner had used some random wheel and the wrong lug nuts.