tire or suspension noise problem?
 

Hey guys,

any suggestions or ideas for me here? i've been trying to figure out a noise coming from what sounds like my right rear tire. it speeds up and slows down with the speed of the car. it's like a womp womp womp noise. almost like the sound of bad bearings.

So i took it to a shop and they said it was the rear wheel bearing. they replaced both and the sound was still there! they shows me some feathering/cupping on the inside of the right rear tire so i was like ok, maybe the bearing problem ruined the tires. i put 2 new tires on and the sound isn't as bad but it's still there.

Now the shop is saying it must be bad shocks and struts. i already paid these guys $1200 for the wheel bearings. how can i tell if the shocks and struts are really bad?

It's an 09 with sports package and 48,000 miles. i've done track days about 10 times and autocross about 8. i'm wondering if driving it hard on the track might cause the suspension to wear prematurely?

for shocks, look at them for leaks.

you sure your front tires arent making the noise? sound resonates inside the cabin so might be worth a shot.
flat spot maybe?

I'm in the same ballpark on mileage on my '09, and a lot more of those miles as trackdays. I haven't had any issue with rear bearings yet (or front, that I know of, but I replaced the fronts once during a diagnosis anyways and they didn't fix anything). It could be the rear shocks I guess; I wouldn't know as I switched to some aftermarket coilovers a while back on mine. There are a lot of other soft joints in the rear suspension, though, so it could be any of those wearing out as well, but most of mine are stock and haven't had an issue yet.

Re: shocks, were they thinking the mount bushings have worn out, or the shock itself is worn out? If the shock itself is worn out, you should be able to tell with a bounce test. Basically bounce a corner of the car (by shoving it up and down pretty hard by hand) and see how it settles when you let go. The shock is a damper for the spring, so if the shock is completely worn out, the car will keep bouncing up and down on that spring for a while. If the shock's working, it should dampen it and stop the car fairly quickly (usual guideline is 1-2 bounces after letting go for it to be still again).

there is also some slight cupping on the inside of the front right tire as well.

Bounce test
 

I did the bounce test on all 4 corners. here's video of the front. i see no bounce at all except the first bounce but i think that was me pushing it.

https://www.youtube.com/watch?v=e-OG...ature=youtu.be

Check for camber and toe while you're at it. "Womp, womp, womp" doesn't really say much. Does it sound like you're driving over cracks on the pavement while you're driving?

look at the rear tire on that side if its not chopped up your looking at a rear wheel bearing .. does it sounds like a helicopter chasing you ? if so its gonna be one of the 2 .. my g35 i had to replace both rears at 60k and i didnt do track days with that car so it sounds about right ..

thats a good description "helicopter chasing you". the shop replaced both rear wheel bearings and did the alignment but i obviously needed to replace the scuffed, cupped, or what ever you wanna call it tires since the damage was already done. hopefully that fixes the problem and the tires don't start to wear like that again.

It could be more than one problem. You've eliminated bearings and tires. I doubt if it is a strut/shock problem because of how periodic the sound is. The cupping problem sounds like alignment, as has been mentioned above. The "womp womp womp noise" could be a parking brake problem, a disc brake problem, or something rubbing on the wheel/tire. Or something else - post a sound clip.