Topic: WARNING -- wheel torque with ARP wheel studs

[snaponbob]

If I have argued with anybody about lug nut torque on ARP wheel studs -- here is my apology. I was VERY wrong.

What's all THIS about? VERY good question. When I switched to ARP wheel studs, I used ARP p/n 100-7702, which is a 7/16x20 thread. The factory studs are 12x1.5. Well, I was admonished that my continued use of the factory torque value of 100 ft/lbs was WRONG. THEY were correct and I was WRONG. What happened? The car was on jack stands for new springs and exhaust. When I put the wheels back on, I was having trouble torquing the rear wheels. Confused as to what the issue was, I switched to a different torque wrench. No luck. So, I said to hell with it and kept turning and snapped a couple studs. OOPS. So, I called ARP and they told me that 90-100 is correct for the 12x1.5 factory studs but the 7/16x20 ARP studs should be torqued to no more than EIGHTY ft/lbs. 

So -------------- if you have installed, or plan to install the ARP studs, do NOT torque them to factory specs, but rather 75-80 ft/lbs.

[Critterman]

And another valuable lesson is learned the hard way.

[Gentleman Jack]

Snapon,

Thanks for the heads up!  Hope the next person reads this prior to snapping a stud!

GJ

[Uranium-238]

D'oh!

[snaponbob]

D'oh!

Eggs ACTLY !!!!!!!!!!!!!!!!! 

[Sly Bob]

Yet another piece of very useful information to put into the memory banks for later retrieval. Thanks Bob for taking one for the team. 

[Ben L]

Better you snapped it in the shop than in the paddock or, worse, on course.

Live and loin.

[Sly Bob]

Yeah, you could have easily ended up like this guy. You must remember this video.

http://www.youtube.com/watch?v=jv4m41viy4I

[snaponbob]

Better you snapped it in the shop than in the paddock or, worse, on course.

Live and loin.

Well, there IS that !!!!!!! And that is what I was telling myself.

[snaponbob]

Yeah, you could have easily ended up like this guy. You must remember this video.

Actually, there IS a story about that. But I am STILL seriously skeptical about the idea of ALL the studs breaking almost all at the same time, EVEN on the INBOARD side. 

[Sly Bob]

The story that I heard about that video is that they had the wrong thread on the nuts that they were using. They were able to make torque but when the took her for the run, the nuts pulled off the studs.

I understand that they now use the proper nuts on the studs. (No kidding)    

[Critterman]

a bad batch?  or to weak for the job and not up to spec

[snaponbob]

American STD (SAE) pitch lug nuts on Metric wheel stud. In other words, they were "stripped" on to the studs.

[boardkat]

The story that I heard about that video is that they had the wrong thread on the nuts that they were using. They were able to make torque but when the took her for the run, the nuts pulled off the studs.

I understand that they now use the proper nuts on the studs. (No kidding)   

this is also the story i remember hearing.
that said, we had a local competitor in an SRT-4 ACR that had simultaneous failure of all 5 factory studs on one corner at an event last year.  he's running ARP now

[Critterman]

The story that I heard about that video is that they had the wrong thread on the nuts that they were using. They were able to make torque but when the took her for the run, the nuts pulled off the studs.

I understand that they now use the proper nuts on the studs. (No kidding)   

Somewho I missed this, makes a little more sense now, but I have to agree with Bob, I don't see all 4 coming off at once. at lest not that quickly.  I have had a wheel come off before after a shop only finger tightened the lugs, and that took miles 30 miles or more before I got a shimmy, and as I slowed down to pull over the wheel took off on it's own, never to be seen again.

[Ben L]

I remember an SCCA autcross school I went to where a newbie in an M3 Beemer (they use short little bolts, not studs) did not torque his wheels down, and the drivers side front came whistling past my head about 20 feet from me like a Civil War cannonball as it spun off just as he was cranking the turn on the last gate of a slalom. 

I never forgot the simple lesson I learned that day.  Torqin' at home is not enough.  Make sure they are torqued before rolling up to the line.

[TravisJames]

Hey snaponbob... you seem to be pretty knowledgeable regarding spacers and studs.  I'm going to install a set of 3/16" spacers on all four tires; is this going to require longer studs?  If so, would the ARP p/n 100-7702, 7/16x20 thread be the ones I need? 

Thanks!

[shabby]

I'm going to install a set of 3/16" spacers on all four tires

Don't install them if you don't need them, unless they're hubcentric then they're fine.

[TravisJames]

They're the 3/16" spacers sold by DDMWorks (http://ddmworks.com/sky/accessories/wheelspacer.html).  Unfortunately I don't have the spacers yet and I don't see anything on their site stating they're hubcentric, they only say they're made specifically for the Kappa platform.  I've been pretty impressed with the quality of products I've gotten from DDMWorks in the past and would be surprised if they were manufacturing these without considering all the fitting/load bearing aspects of design.  Regardless, I would be really interested to know peoples opinions regarding these particular spacers and whether or not I'll need longer studs.

Thanks again!

[Acadian]

Thanks for the heads up snap-on bob.

Critical information that needed to be shared with the rest of us.

[Critterman]

James - I ran these (DDM) on the front when I ran the stock wheels with the 4 piston brake kit.  Didn't need them on the rear.  It is a close fit and if you are going to be slaming the car around, I would go with longer studs.

[Divingsolo (formely Randy@DDM)]

We can supply the proper 12x1.5 ARP longer studs...I don't think we have them on the site, but just give Dave a call or email and he can get you pricing.   I've been running these for over two years now.  You do have to run an open style lug nut with these.

[snaponbob]

We can supply the proper 12x1.5 ARP longer studs...I don't think we have them on the site, but just give Dave a call or email and he can get you pricing.   I've been running these for over two years now.  You do have to run an open style lug nut with these.

Randy, the ARP 100-7702 (7/16 x 20) has a .580 knurl. The 12.5 x 20's (100-7708 and 13) has a .508 knurl. http://www.arp-bolts.com/catalog/catalog.html The .508 may be too loose as the .580 is not a real tight fit at all. 

BTW, I left a message over the weekend about some braided brake lines. Please let me know.

[snaponbob]

With stock wheels, there is roughly a lug nut engagement of 8 turns. A 3/16" spacer will eliminate 3-4 turns of engagement. NOT enough to safely secure the rims. Spacers = longer studs.

[Divingsolo (formely Randy@DDM)]

Bob,

Those are not the bolts we are using. The ones we sell have the proper knurl size.