NitrogenBalance

Installed some stainless lines and motul RBF600 on brakes yesterday and found one of my wheel bolts a little wooblely and apparently loose. Jacked the car up and took both wheels right off. Very carefully inspected and cleaned the remaining 9 bolts and found one from the other side to be cracked also. So I broke one from each side of the rear. The fronts I checked also to be careful. I'm going to get the specs from these and see if there is something safer/stronger available.

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The bolts where torqued to spec. so my only guess is the abuse I put the car through recently did this I guess this weekend calls for cold beer and removing the remaining stud left in the hub at lease only one stuck in there..

AMG140.6

Time for ECS Tuning's racing studs.

Just make sure you use Red Loctite when you turn them into the hub.

www.ecstuning.com.

NitrogenBalance

So would one replace the "bolts" with "studs" and switch to using lug nuts instead of lug bolts? I could only find the studs on the website.

I was going to measure and order some new ones today. Turns out the popular "RAD" brand for MB is the same brand I just snapped. I also have a gut feeling that the bolts I got with these Renntech wheels are a little short possibly as it seems my OEM bolts threaded a bit deeper. Soon will know.

AMG140.6

Yes, ditch the bolts for the H&R stud kit. Get them long. At least for the rears.

This will be very useful when you go to NED and want to switch to Hoosier slicks once you're there.

NitrogenBalance

Interesting, I'm going to look into doing this, I like the idea.

email or post up some stuff about your audi. That car sounds great, I wish you got up to NED I would have loved to see it run and there was an RS4 at the rental day.

Ausmbtech

What rims are you using? Are they genuine?

If they aren't genuine and the hub center is larger than the hub and you don't have an adaptor then the wheel bolts get much larger shear loads than intended.......maybe the cause?

PTE

I looked at those broken wheel lug bolts . They are for a taper style wheel seat. . So I went out and looked to see what I had on my 2003 CLK 5.5 . They are the Ball style type and had a much large contact print on the seat area in the wheel and on the bolt . Your Pictures show a Narrow contact print . Just my observation. I maybe all wet/
___PTEngineering

NitrogenBalance

PTE, good to hear from you. The T-stat and thermos are working great

The wheels are renntech's finest. Doing some measuring I found that the bolts were a little short also. Threading 5mm less into the hub than the stock bolts/wheels. I'm going to order 5mm longer bolts and I'm going to confirm the seat is the right one for the bolt/wheel combo...I think it is...seems like something I would have picked up on right away.

PTE

I took the time to check with Scotty @ Renntech. Their wheels do use the Cone typo of seat. With steel threaded bolt into a steel componet , the engagement should be at lease the diameter of the bolt , at Minumum. A steel threaded bolt into a alum alloy componet , should be a minumum of 1 1/2 the diameter of the steel bolt. I know I got laughed at , the track rentals at Moroso in WPB FL. because I was running around with my torque wrench checking lug bolt torque after some of the guys made a run or 2. Of well , safety First !. Cheers ___PTEngineering

NitrogenBalance

Eh' something typical of an engineer to check and a non-engineer to laugh at. I checked mine the day I left for the track thats how I'm sure it was the culprit along with being the wrong size...how scary to think of the maniac things I've done with improper lugs. You can never check/measure too many times, especially when safety is at bay. As a past and very brief engineer I can't always engage but very much enjoy your posts and help PTE!! Great info on the steel/alum and steel/steel thread depths which I assume is related to as "engagement". Thanks so much.