But you said earlier in this thread that you've been using them with no issues. Hahah

 

I've been using mine for two years. Uh oh. LOL
It's only about 1000 miles, but they were hard miles.
I still prefer the bolt-on spacers, though. ARP or not, extended studs have a lot of load on them, from different directions, with very little support. Not for me.

 

You're bolt on spacers put a very nearly identical load on the studs they bolt to on the car.

 

I'm no engineer, so you may be right. I just feel better putting the load on 10, shorter studs than all that leverage on five long ones. I can bend a long bolt easier than a short one.
Until I could find some proof to the contrary, that is. I've actually never had a need to worry or research it.

 

Your 5 short studs at the hub are holding the bolt-on spacer and wheel on just the same as 5 extended studs. The stud on my car sheared at the very base of the threads, right at the knurl.

See here:
http://www.maximummotorsports.com/te...s_spacers.aspx

As Rjones pointed out, my studs were likely fatigued and not able to maintain tension, causing a failure. It also didn't help that they were likely not the highest quality part that could be on the car, which likely caused them to fatigue quicker, and fail, Or maybe the pot metal spacer was compressing a bit under load, who knows.

It also probably didn't help that I only had 20 minutes between my last two sessions, so I had to check the lug nut torque while they were still nice and toasty, which isn't a good thing to do.

 

Possibly. Like I said, I'm no engineer.

 

Letsgetthisdone, where your spacers hub centric?

 

Yes, hub and wheel centric.

 

the ARP studs are made from quality metal. nothing preventing you from using ARP studs with a bolt on spacer, you just have to cut off the extra length.

the wheel/spacer should be held in place by the friction resulting from the clamp load applied by the studs, not by the bending strength of the studs. the main reason studs fail is because they are under torqued and allow the wheel to move around and eventually fatigue the studs. The better material strength of the ARP studs, if used with suitably strong nuts, allow higher torque values to handle the increase loads racecars generate. I torque the ARP studs with blox scm435 nuts to 110-115 ft-lbs. that's with 25mm spacers up front with only the extended arp studs. the good news is that by torquing them high they will break in the paddock when they start to get weak instead of on track, which saves you much money and headache.

 

The wheels don't mind that much torque?

 

Yeah.....I forgot about that. I honestly think that it didn't have anything to do with the spacers, more fatigue than anything. I had those studs on for 4 years, with the wheels being removed ~every other weekend during that timeframe.

 

No. The aluminum wheels on trucks with 14mm studs and conical lug seats get torqued to 120-140ftlbs..

 

Haven't been on here in a while and interesting topic at hand.

Letsgetthisdone-glad to hear you're OK man that could have been significantly worse as Im sure you're aware...

I too an running ARP's all around and a 18mm spacer with my 18x10.5 NT03's and I almost had a close call this past summer. I typically torque my studs to 90ft/lbs and retorque them before every auto-x. Well, I ran a Sat and Sun event and not sure I retorqued them Sun morning. Car ran fine however driving home I had a huge vibration in my wheel so I opted to pull over and check everything out. Needless to say I was very lucky as I found all 5 lugnuts on my passenger side were finger loose.

Also, when I put on my snows a couple months back I snapped one of my ARP's upon torquing them. Would this be contributed to them weakening when my lugnuts loosened up or from overtorquing them?

I just popped in a stock stud as that's all I had on hand and like I said was throwing on my snowtires so it didnt matter but I do need to install new ARPs soon. Would it be wise to replace all 5 on that side?

 

Yea, It could have been much worse. Car in front, a different part of the track (like going into the chicane or turn one at 115-120), or it could have happened on freeway overpass and slammed the car into a wall. I was definitely very fortunate.


I just got the first body shop estimate back, $3,250 . Includes repairing my bumper, new lip, new side skirt, new fender, and repainting the whole front of the car (rock chips on the hood and a few on the passenger fender I want fixed from street driving).


If one stud broke, I would replace all 5. I think they come in 5 packs anyways...

 

My Duramax's lugnut torque spec is actually 165ftlb.

A certain someone who has access to a materials science lab did some testing on ARP studs and came to the conclusion that they should be torqued to ~120ftlb based on where they started yielding. That's what I've started torquing mine to since the failure.