sebdavid

Hey guys,

I have had a long stud (believe ARP) break on the rear left during an event at Tremblant. I could swear I torqued that wheel properly, but human error is always possible.

Started getting a vibration right at the outset of the session, thought I had lost a wheel weight or something. Vibration got worse, so I reduced the speed and then the stud broke all of a sudden in a high-speed right-hander. Lucky I didn't lose a wheel altogether!

Now remaining 4 studs are loose, wheel holds torque and I could drive back home on 4 studs/nuts with no problem, no vibration. Wheel is damaged and needs replacing as the holes are not looking great.

1) I believe I will have to replace the whole hub/bearing assembly, right?

2) Do I have to replace them in pairs?

3) Do you guys use anti seize on the studs and especially on the nuts where they seat on the wheels? I have been told this may have been my problem as I keep changing wheels all the time and that area is a bit scruffy with aluminum on the nuts, hence maybe some of the torque I put in when torquing the wheels is friction instead of tension?

4) Perhaps most importantly: do you preventatively change the studs once in a while? What about the whole hub? This one had been on the car probably for many years as it was there when I bought it.

Lesson learned: when there's a weird unexplained vibration, come in instead of assuming it's an unbalanced wheel, and re-check torque and visually check all nuts and studs. Fortunately I backed down when the vibration got worse and when the stud broke, I didn't even go off-track.

GAS

[QUOTE=sebdavid;1581635247]Hey guys,

I have had a long stud (believe ARP) break on the rear left during an event at Tremblant. I could swear I torqued that wheel properly, but human error is always possible.

Started getting a vibration right at the outset of the session, thought I had lost a wheel weight or something. Vibration got worse, so I reduced the speed and then the stud broke all of a sudden in a high-speed right-hander. Lucky I didn't lose a wheel altogether!

Now remaining 4 studs are loose, wheel holds torque and I could drive back home on 4 studs/nuts with no problem, no vibration. Wheel is damaged and needs replacing as the holes are not looking great.

1) I believe I will have to replace the whole hub/bearing assembly, right?

2) Do I have to replace them in pairs?

3) Do you guys use anti seize on the studs and especially on the nuts where they seat on the wheels? I have been told this may have been my problem as I keep changing wheels all the time and that area is a bit scruffy with aluminum on the nuts, hence maybe some of the torque I put in when torquing the wheels is friction instead of tension?

4) Perhaps most importantly: do you preventatively change the studs once in a while? What about the whole hub? This one had been on the car probably for many years as it was there when I bought it.

Lesson learned: when there's a weird unexplained vibration, come in instead of assuming it's an unbalanced wheel, and re-check torque and visually check all nuts and studs. Fortunately I backed down when the vibration got worse and when the stud broke, I didn't even go off-track.[/QUOTE

Don't ever forget the lesson you learned. The car is telling you there is a problem and at the speeds we run only bad stuff can happen if you don't listen! The hubs wear out over time and with the broken stud it is probably a good time to change that complete hub and add new studs. It is not an overly difficult task if you have some tools and are a little motivated. I just replace the hubs individually as they wear out. I never use anti-seize. We have moved the ARP studs from hub to the next hub 2, 3, or 4 times, so yes you may use them over. We switch wheels/tires six or eight times per race weekend.

GOOD LUCK and listen to the car!

Cobra4B

1. I've never seen or heard of an ARP stud breaking, but I'm sure it happens.

2. Usually studs break due to being over-torqued. 100 ft/lbs on your torque wrench means 100 ft/lbs. Not click and then "a little more". Again... usually ARPs can take a little extra abuse.

3. Stock studs eventually wear out after enough on/off cycles of the lug nut. Every time you torque the lug you stretch the threads (this is what creates the friction to hold it on). Eventually the threads fatigue and it's done. The nut will run on and torque fine, but when you go to take the nut off it will gall and get fused in place. Again... never seen this happen with ARPs, just stockers.

4. Using some anti-seize is a huge area of debate. Many will tell you it's a horrible idea and you'll die. The GM torque spec is for a dry thread and using lubricant increases the resulting stress on the threads. So 100 ft/lbs using lubricant is tighter than 100 w/o. Personally I always use a tiny dab of anti-seize to prevent galling. Whenever I try and run new studs/lugs dry I have issues taking the lugs off at the track. This is using brand new top-end components (ARP studs and Gorilla stainless lugs). I'm sure the next post in here will tell you about how much I'm wrong on this, but it's been my experience that I need a little anti-seize and I torque to 100 ft/lbs and never had another issue with lugs/studs.

5. No need to replace in pairs, but if they're old and you're tracking the car you may want to consider replacing them with new SKFs. You can also get the OEM bearing (made by Timken) from Auto Zone for far cheaper than the stealership. Many folks replace them one at a time with SKFs as they wear out and start to roar/grind. You can hear/feel a bad bearing.

6. As for preventative changing of hubs/studs... depends on your $$$$ budget. Those with lots of it will tell you to change the hubs once a year regardless of how they're performing. If you were W2W racing a full season 8+ events I'd probably agree. However, for the average amateur racier, let alone the HPDEer, I'd just replace them as they start to make noise. That said, I inspect them like a hawk before each track weekend. If I was using stock studs I'd change them periodically as they do wear out, but with ARPs it's one and done.

7. Listen to your car... it will usually communicate if something has changed. If you hear/feel a change then something has changed!. Too many people will say, "Oh it's nothing... oh it'll go away...". Now I'm not saying come in every time you feel rubber globs on the tires or a slight pulsation in your pedal, but over time you learn to feel what's normal stuff vs. an actual change. Completely disregard if you're racing and it's the last few laps.... then run it until your crash or it blows up

sebdavid

Always torque to 100ft/lbs, never more. But then again I don't know what the previous guy did.

I probably put on much MORE wear and tear on the car than the average racer. I do 30-40 days a year and that's 1.5-2h running every day. I'm now using scrub slicks so more Gs, and the car is heavy and powerful.

Then again, don't discount human error, if I was viewing this externally I'd probably go with the "idiot did not torque his wheel properly" theory.

Thanks for the advice on not necessarily replacing in pairs. I might do it anyway for peace of mind and keep the old good one as a spare, although the right one doesn't show any sign of wear.

My issue now is whether I should find a local shop to do it or drive 5 hours to Powell's shop on 4 studs/nuts. It held up coming back home yesterday but that was only a 2.5 hour drive.

RX-Ben

Swapping a hub is a pretty easy swap, assuming you have the tools (the oddball piece is a T55 Plus torx bit).

Olitho

If the stud broke I doubt it is an ARP. I bet it is one of the long GM studs.