Rear wheel/tire noise

[GulfCoastAquarian]

My 2001 BMW M3 was pulling slightly to the right, so I had an alignment done before a 1200 mile road trip to NJ and back. During the trip, a noise from the right rear wheel/tire became progressively worse, to the point where it was deafening as I pulled back into town.

Conditions for the noise:
1) It's a loud, oscillating drone like an uneven whirring noise. Phonetically? Woo, woo, woo. Increasing in speed with vehicle speed.
2) Particularly bad at 25 mph and 45 mph.
3) Makes noise going straight, or during a turn. It seems to ease up a bit when I make a hard right hand turn and unload the right tires.

My Michelin Pilots were worn to the indicators, so I figured they must be the culprit. Just had a fresh set of Goodyear Eagle F1 A/S tires installed, and the problem is the same. What the heck?

Here are my alignment specs:
http://images30.fotki.com/v40/photos...0071119-vi.gif
I just noticed he didn't bring the right rear camber to within spec. It remained -0.9 degrees, although the spec is -1.3 to -2.3
Would this be enough to cause this sort of severe noise? The tech at the tire place noticed very, very slight cupping, but not enough to cause this kind of noise.

Wheel bearing? Aren't wheel bearing noises affected by side loading?

I just changed the pads, so is it possible the caliper bolts might have worked themselves loose? Seems like the noise would go away under braking, then. And it doesn't.

[curtis73]

sounds like a bearing to me.

[MagicRat]

Originally Posted by curtis73

sounds like a bearing to me.

I agree. Also, in anticipation of your next question, I do not think the poor alignment, worn tires or the long trip had anything to do with the bearing failure.

The design, materials and precision of the assembly process has everything to do with it.

Unless the mileage on the car is very low, consider doing both rear wheel bearings. Even if the left rear bearing is quiet now, it may fail soon as well.

[GulfCoastAquarian]

Originally Posted by MagicRat

I agree. Also, in anticipation of your next question, I do not think the poor alignment, worn tires or the long trip had anything to do with the bearing failure.

The design, materials and precision of the assembly process has everything to do with it.

Unless the mileage on the car is very low, consider doing both rear wheel bearings. Even if the left rear bearing is quiet now, it may fail soon as well.

Thanks for weighing in. I've got an aftermarket warranty that is going to cover the failed bearing. Once it is quiet, if I can hear the left rear making noise, I may change it myself (only $75 in parts). The car has 53k miles.

I'm sure it was well on its way towards failure before the road trip, but keep in mind the road trip was to New Jersey , with a trip across the Cross Bronx Expressway, to boot. Those roads are absolutely pitiful. And with a stiff suspension and low profile tires, if that bearing was on its last legs, the NY/NJ potholes did it in for sure.

[GulfCoastAquarian]

Dealer just called and verified it was the bearing. I guess it should have been more obvious. I'd just never heard a bearing oscillate like that. I have had bad luck with bearings, though! My first post on here was also a bearing issue with a Mitsubishi Galant!
Also, the fact that it coincided with the alignment and road trip was throwing me for a loop.
Thanks!