cstreit

So in my last 3 events I broke a wheel stud every event. Luckily at two we were able to extract the stud and get an emergency replacement. At the last two a fellow cup'r loaned me a spare center-lock setup to get through the day.

So it seems that these studs do tend to break regularly. At a minumum I'm going to replace them all this winter, but wondering if I should just go back to center-locks.

Any downsides (other than the expensive torque wrench) ?

Thanks

Glen

C locks for sure...

Derek@TRG

If you decide against center locks i have plenty of studs in stock.

amso3

Chris

I was crew chief on 996 and 997 Cups in grand AM for 5 years. I only saw a couple studs break. I think they will be fine if treated properly. I'd replace all of them when you get time and go from there since you don't know the history of the current studs.

cstreit

THanks guys,

At a minimum they are all getting replaced... I have to assume someone overtorqued them at some point.

Any real reason to go one way vs. the other (centerlocks vs. studs?)

tcsracing1

i find studs more durable towards abuse.

what brand/make studs do you have??

IPguy

Pricing?

cstreit

No idea on the brand of studs. they are shorter than the Porsche ones and have a silver finish. second on the pricing request....

Derek@TRG

I have press in studs, made by ARP, 92.6mm total length, 78mm effective length, 14mm leader.

These are the studs we used in our Grand-Am cars when they were 5 lug. We had no failures with these that i can remember, not counting cross threading dring a pit stop, which was very rare.

These studs are $20.00 EA.



IPGUY, if you are looking for studs for the GT3 pictured in your avatar you will need the thread in studs we have, also made by ARP, 74.25mm overall length, 60.5mm, effective length with a 19mm leader

These are also $20.00 EA

cstreit

Derek,

Mind have all broken at the shoulder right where they thread into the hub itself. Seems like a stress riser forms there as the 4 that I have broken now show signs of extended fatigue before failure.

Is the wider shoulder flange on these designed to sit on the surface of the hub? Seems like this would help prevent lateral roking and repeated stress fatigue/cracking.

Thanks!

dan212

I think they are a wear item and replace all of them every year.

Derek@TRG

Chris,
On the thread in studs, yes, the shoulder sits on the hub, these were used on our GS cars and we never had one break.

They are a wear item and we did change them half way through the season. Keep in mind we did pit stops and pit stop practice, so they did see a lot of stress.

jrgordonsenior

Miss my cup's center locks. Much easier to deal with than 5 lugs. That said I bought the longest I could find from CDoc so I could use spacers. 90mm IIRC. With BBS-E88's 9's and 11's I can barely get full thread with 7mm spacers. Just takes a little tugging and rolling on the fenders......

smsarchitects

CL

Apex996

If properly designed the studs should not touch the brake hat (or wheel), therefore when located and torqued there "should" be no lateral movement as you put it.

The hub's threads should be inspected. A stud that is not well supported by the threads when torqued is effectively a loose stud and will allow the aforementioned lateral movement of the wheel under braking and acceleration. When using Loctite to fix the stud into the hub make sure the wheels are mounted and torqued before the Loctite dries. Otherwise the final torque may break the Loctite and may allow the stud to loosen during wheel changes.

... more info here:
http://www.track-studs.com/ProductInfo/stud_info.cfm
and
http://www.track-studs.com/ProductInfo/stud_install.cfm

If all is well with the car, a set of these thread-in studs can last through years of track use. I have a set of 80mm & 90mm Pro Series studs on a track 7 GT3 going on the 3rd year and 6 C2 that are going on 4 years. Inspected regularly of course while changing tires.