NeverEnoughBoost

So when I first got my 2012 A6, it was as smooth as glass. And now, I've tried everything to get the car to stop shaking at higher speeds, and even the brand new brakes have that warped feeling (which could just be uneven pad bed-in) even though I performed the bed-in process exactly as it describes. I've taken the car to 3 different tire places to balance (audi dealer being one of them), check for match-mounting, or just tell me the tires are bad and need replaced, but they all give the car back to me saying they have mostly fixed the problem but I might still feel a small shake because of some tire run-out on 2 tires. I'd like to feel zero shaking like when I first got it. The tires are pretty much new. I got them last summer and I didn't use these wheels in the winter. I have another set with snows on them. My questions are:

Why am I getting the car back from these places with the same issue, while they are all telling me the balance was off and weights had to be added to different spots?

Why do the brakes feel warped at higher speeds even with the correct bed-in? Could it be because of the tires?

Will driving with this crappy shaking and brake vibrations cause other parts to wear faster or become damaged if I'm getting sick of taking it to places?

What can I do to make it feel like an Audi again without getting hosed?

Recently I've replaced both front wheel bearings. Is it possible they're bad and causing all of this shaking, or would the dealer have picked up on this from the beginning?

Thanks. I'm so frustrated that I'm looking at used Audi's to possibly trade it in. I love the car, just not right now.


****PROMLEM SOLVED**** The hubs were about 1mm undersized (65.5mm) so I wrapped some aluminum tape around the hub so that they measured 66.6mm and it fixed the vibration.

uberwgn

What do you experience with the winter tires/wheels?

NeverEnoughBoost

I took them off months ago. I know it wasn't nearly as annoying with those, but they are a little loud and obnoxious just because they're winters. I don't really remember them shaking at all though. Maybe I'll put them all on and take it on the highway and see how they spin compared to the summers. Good idea. Maybe that'll narrow it down to a tire issue. I still expect the brakes to pulsate a bit though. Would it be a terrible idea to do the bed-in a second time or would I need to burnish the rotors to remove the pad material and start over? Thanks

Fahrer

I don't know if these cars have a center bearing for the drive shaft but some Porsche Cayennes and VW Touaregs had a severe vibration problem on the highway caused by the central drive shaft bearing failing.

NeverEnoughBoost

Interesting. I had an EVO with this issue and didn't even think of it. That's something to look into. Its a very weird intermittent vibration. I can be crusing at 75mph and feel nothing for a couple minutes, then slowing the vibration comes back, then slowly goes away and feels pretty smooth again, etc, all while traveling at the same speed. It's like an oscillating vibration that comes and goes. It's weird though because when I hit the brakes while it's shaking, the vibration gets worse with light braking, and smooths out with normal to heavier braking. Almost feels like the brakes are what is making it shake, but I think they're 2 different issues since I just replaced the brakes. The old rotors shook waaaaaay more, and these new ones were smooth as glass for the first 500 miles, which is why I suspect bad bed-in. Also, for those first 500 miles that the brakes were great, the wheels still had the shakes.

uberwgn

I think you've got to do that and begin to eliminate some things.

Don't mix brake issues with out of balance tires/wheels.

Have you seen the tires/wheels spin on a balancing machine? One can learn quite a bit from that simple check.

These cars do seem to be more sensitive than others when it comes to having tires/wheels that are perfect or close to it. I chased a problem on our A6 wagon for a couple of years. It really annoys me that the people in the tire shop were not astute enough to identify and eliminate a couple of tires that had bad tread squirm. They just kept re-balancing and telling me 'that should be better'. It was a joke until another shop sent me a video of the tires spinning on the balancer. I would have thrown those tires away much sooner if I had seen that. Those tires were never going to be made right. I ended up buying 4 new tires and the car is perfectly smooth again on the highway. I wasted a lot of time/energy on that exercise. Bad tires do happen. Also, you must eliminate the possibility of bent wheels.

uberwgn

That's exactly what our car did on longer trips. You could tweak the cruise control up or down slightly and the vibration would go away for a bit.

NeverEnoughBoost

Honestly I'm hoping it's just the tires at this point. With the money I've spent on balancing lately, I could have gotten at least one tire for the cost. The rims were new last summer so I doubt they're bent but crazier things have happened I suppose. The shops told me the wheels were straight and just a couple tires had slight run-out but that they shouldn't be that bad after the re-balance. Maybe they don't realize my expectations. I'll switch to the snows and start there.

uberwgn

Road Force balancer might help is everything else looks OK.

NeverEnoughBoost

Audi did a road force balance and they didn't even bother trying to reposition the tire on the rim even though one tire was over the recommended limit. I think they said one was around 18-20lb road force, and you want them all to be in single digits from what I've read. They just balanced them all the best they could and said "it should be better but you may still feel something." $100 down the drain...