I have a 2001 A4 Avant qtm that originally had an AWM 1.8T. These cars came with the larger front wheel bearings (similar to the V6 cars). Because of the larger wheel bearings, there's very little space between the hub and the bearing housing (aka. the uprights), so the bolts used to secure the wheels to the hub need to be a very specific length to prevent them from bottoming out against the bearing housing when torquing down the wheels. Because I run 3 different sets of wheels throughout the year (Summer, Winter, track) that all have different flange thicknesses, I choose to run wheel studs instead of bolts. This prevents me from having to deal with 3 sets of wheel bolts of varying lengths.

For the past few years, I've run 034 Motorsport studs without issues. But last year, I needed to remove them to accommodate some Porsche wheel adapters, and the threads got damaged in the process (they'd been on there for over 4 years). So when Winter came around, I needed to buy new ones. I wanted to get the same ones again, but 034 Motorsport didn't have enough in stock, so I ordered a stud kit from ECS Tuning instead. As soon as the kit arrived, I installed it, mounted my winter wheels, and went on my way.

Fast forward 5k miles, and both my front wheel bearings are shot at exactly the same time. I needed to replace them urgently, so I did the job in my driveway during a cold snap in over a foot of snow. Upon taking the brake rotors off, I noticed that the studs I bought from ECS Tuning screw in too far past the hub and bottom out against the bearing housing. This was pulling the hubs against the bearings, which caused the premature failure. Anyone who's done a bearing job on these cars knows what I'm referring to. The studs do have a shoulder on them to prevent them from going in too far, but that shoulder isn't placed consistently on every stud, and it didn't do its job on 5 of the studs (2 on one side of the car, 3 on the other). I did screw in the studs only by hand, but when torquing down the lug nuts, it's a crap-shoot whether only the nut will turn, or the entire nut/stud assembly, so that final tightening can cause severe preload on the bearings. Here's a photo of the issue:



You can't actually spot this issue with the brake rotors in place, and who removes brake calipers and rotors to install wheels studs?!?

So my only recourse right now is to thread the studs in "just enough", then tighten the lug bolts using an open wrench while I keep the studs from turning with an allen key. It's a super tedious process and it takes much longer than just spinning the bolts on with an impact wrench and then tightening them with a torque wrench. Especially since the studs have rusted pretty bad during this one winter (the 034 Motorsport studs never rusted in 4 years of use).

ECS Tuning refuses to stand behind the product. All I wanted was store credit, I wasn't asking them to cover the cost of damages or anything. I've contacted them numerous times over weeks, got the end-around multiple times before finally getting an RMA number. They want me to send them back a bunch of rusty studs and lug nuts at my cost. I've got no other way to attach the wheels to the car in the meantime, and 034 Motorsport still doesn't have enough inventory of the better wheel studs. So short of having my car on jack stands while I pay for the studs to travel slowly back to ECS Tuning, my only choice is to keep dealing with these sub-par, defective studs. The RMA will expire before 034 Motorsport gets more inventory of the proper studs.

So... if you've got a big-bearing B5 A4 or B5 S4, avoid this stud kit at all cost. There's a very good chance you'll end up with defective ones, resulting in expensive damage to your car that's super tedious to repair. Heck, even if you've got a small-bearing car, I'd avoid it anyways. It rusted in no time at all. Buy the 034 Motorsport variant instead. It's cheaper and much higher quality. Just be ready to plan ahead since they don't seem to keep enough inventory on hand.

 

Quick update: in response to the negative reviews I left on Facebook and other review sites, ECS Tuning got back to me and decided to give me store credit for the stud kit after all without having to send it back. In addition, they'll check the fitment issue I reported and either amend the description or have the product fixed. It took 2 weeks of being ignored and dismissed, and I needed to make the whole thing public (which I hate doing), but at least they're acting on it now.