I know everything is in balance and they aren't too tight. But everytime I throw Nittos on the back I break the damn wheel studs when I hookup. I mean the wheel doesn't go flying off, but when I check them afterward 2-3 out of the 5 are shot. I've been replacing them with the grade 8 bolts and nuts from Carquest. What are the STRONGEST wheel studs and nuts that I can put on. I'm tired of this.... Thanks in advanced...

 

Do they actually break or do they strip???

 

Grade 8 bolts and nuts? Are these wheels studs, or bolts from the hardware bin? My understanding is that wheel studs (say ARP P/N 100-7708) are a stronger grade than grade 8, I think it's called grade 12, but not sure about that.

Dave

 

NO WAY that those are designed to handle a 3500 lb car launching! Use ARP wheel studs, 12mm X 1.5, 2.5" length. Thunder Racing has them, and they are infinitely stronger than Carquest crap.

 

Try the ARP wheel studs for your car. They are 190,000 psi tensile strength, which is about as strong as you should use. As steel strength increases it 'stretches' less before it fails. At 300,000 psi, about the compressive strength of a ball bearing, or needle roller, enough bending stress will cause an explosive failure.

Are you using wheel spacers by any chance? If they are thicker than maybe 8 mm (5/16), you could be bending the studs rather than shearing them. Bolts/studs don't like bending stresses. A 3/4 inch thick spacer would probably fail studs regularly with your traction.

My $.02

 

I use to strip my rear studs with my 1/4" spacer. I finally went with the front studs in the rear and the problems went away. Apparently not enough threads available. The fronts are almost exacly 1/4" longer.

 

Grade 8 fasteners have an ultimate tensile strength of 150 000psi, with a minimum elongation of 12%. Be careful if you use any type of lubricant on the threads as it will make HUGE differences in initial bolt stretch vs unlubricated for the same amount of torque applied. ie if the threads are not to be lubricated and you do, you can overstress the stud or break it just when toqueing it.

The ARP bolts are most likely a rolled thread (although the carquest jobbies might be too) which does not have as sharp a valley between thread pitches which does not create as large a stress concentration.

 

I was tempted to go to 1/2" studs when I upgraded my rear end, but I ended up using stock diameter ARP studs and haven't broken one yet (with launching off the brake in a 4,000lb car and >800rwhp). So, they should be strong enough.

Do they break on both sides or just one side?

Rich Krause

 

Wow, sorry guys. Didn't think you all would pick up on this one that fast.

They are standard, supposedly stock, replacement bolts and nuts from carquest. I just assumed on the grading of the steel. I am not using spacers and it is with stock rims. They seem to break evenly on both sides. I've cracked 2, but they generally just strip. I can only launch at about 2 grand to prevent wheel spin even with the street slicks. I want to get true slicks but I am afraid to with this stupid issue. I'm not using any lubrication on the bolts. I think I just need something stronger. I'll try the ARPs from Thunder and see what happens. Are those the strongest ones available?

 

Yes. If you read Rich's post and read what kind of abuse they can handle on his car, you're probably gonna be fine.

 

Thanks for all the help everyone. I am full aware of the tq and abuse that rich is putting down. The question was only asked because I am the type of person that thinks you should replace broken parts with the best possible replacement.

 

Not a bad plan!

 

Rich, I hope you plan on replacing those studs soon, and very often.. I've seen a couple 1/2" stud failures recently and it isn't pretty. In fact it's ugly enough for me to switch to 5/8" studs.

Most if not all of the drag radial racers are going to the 5/8" studs, general consensus is that the tire shake from the radials is weakening the studs to the point of failure.

good luck!

 

I believe there are wheelstuds made out of chromoly too which would be stronger than steel so you might wanna give those a shot if nothing else works for you.

Myles

 

Read through them all, but I've yet to see anyone mention that the wheels studs are lightly press-fit; The grooves on the shoulder of the stud and the way it closely mates to the flange has surely have to add to it's structural strength.

With that said, I wonder if any stud will mate again into the axle's matching grooves after running bolts with smaller shoulders in the same holes. I'd say it's worth a quick look....

Hope it helps...