Problem with Currie axle, wheel studs? - Lateral-g Forums

Novelli · #1 10-06-2009, 01:45 PM

The green 67 Chevelle that we built was out with the owner yesterday, when the owner returned back to the shop I noticed that there was a lug nut missing! After further inspection I noticed that it has broke the wheel stud. Three other wheel studs are ready to check out on that same wheel as well. The wheels are billet specialties,(and yes they were torqued) and the axles are Currie. I know the owner drives the car hard, but it def shouldnt be sheering off wheel studs? I am wondering if there was a bad batch of wheel studs out there and I happened to get some. The studs were already in the axles when they came from Currie. Thanks

Vegas69 · #2 10-06-2009, 01:47 PM

That's a scary deal. I'm sure currie would never own up to it. Stick a set of arp or moser studs in the axle. Are you sure the wheel is seating on the axle flange?

Novelli · #3 10-06-2009, 01:58 PM

The wheels are seated, everything looks fine! I am very suprised to see this. The car prob would have sheered the rest of the studs off if it was hammerd on one more time!

Vegas69 · #4 10-06-2009, 02:07 PM

Are you getting 8 full turns on the lug nuts?

**XcYZ** · #5 10-06-2009, 04:41 PM

What size are the studs? I'm assuming 7/16" ?

**Steve1968LS2** · #6 10-06-2009, 05:23 PM

Also, new aluminum wheels need to be torqued twice.. this same deal happened to my Fairlane when I put on the Vintage Wheel Works wheels (strange axles).

Bryce · #7 10-07-2009, 11:25 AM

are the studs long enough? do you have at least one stud diameter threaded into the hex of the lug nut.

Apogee · #8 10-07-2009, 02:50 PM

There are several possible reasons for breaking wheel studs, but usually it can be tracked to being either over-tightened, under-tightened, or not fully seated. As Steve pointed out, you need to retorque new aluminum wheels several times every 40-50 miles or so (unless it's being flogged, then more frequently) until they hold their torque values due to the conical seat on the lug nuts work hardening the conical taper of the seating surface on the wheel. I'm guessing it was torqued to spec for the wheel stud size when it left and then as the wheel material contacting the lug nuts yielded, the torque was lost. Once the studs are loose, they fail remarkably quickly and with minimal loading. Have you calibrated your torque wrench lately?

Too little thread engagement will usually lead to stripped wheel studs, not broken studs, but you do want at least 8 turns egagement as a general rule. It's possible that you received a bad batch of wheel studs, but not all that likely in my experience. Hydrogen embrittlement caused during zinc plating can compromise wheel studs, or any plated high-strength fasteners for that matter, but they're supposed be baked post-plating in order to release any captured hydrogen. If the wheel studs are not electro-plated, then that would rule out that possibility.

Tobin
KORE3

JRouche · #9 10-08-2009, 11:15 PM

Good responses. One more that might cause it. Bolt circles are off. Either on the wheel or the hub. If the bolt circle is off for example on the wheel (not likely but possible) or the hub then you will be pulling the stud over when torquing and with the way studs are fully threaded they cant take a shear load.

Just a thought and maybe something to look at. Easy to measure the bolt circles and see if any are off. And because its the same wheel I would check the hub first. Kinda suspicious that they are all on one wheel. Kinda points to a mismatch on that hub, not the batch of wheels or the studs. JR

Novelli · #10 10-10-2009, 05:25 PM

Update! The wheels were re torqued after a couple hundred miles, the car now has about 1k on it. So yes they were double checked. I just checked the torque on the wheels and both rear wheels killed some studs. The drivers side rear broke some, the pass side rear has tweaked some, and the front wheels are just fine and still torqued to spec. The front hubs are from a different company and have a different stud. I believe the fronts are ARP studs. The wheels use a tapered style lug, not a sleeved style like a drag style SFI approved wheel. It is acting like the rear studs stretched and got loose. The car has only had about 500 miles on it since they were last checked. The car is only putting around 500 HP to the wheels, and has radials on it, so no it does not hook up. Just some food for thought?