Tire wear questions

Took my car (2001 525i) to my trusted BMW indy for what I thought was a rear wheel bearing. I had planned to do them myself, but time and lack of a couple tools made that problematic. In any case, he checked and found no noise at all from the bearings. Looking over the tires (BFG Sport Comp-2), he found cupping on both edges of all four, as well as a fair bit more general wear than the 15k miles I've had them on the car would suggest is normal (note that I rotate these front-to-back each year when I pull the snows, so all four have seen service front and rear). He theorizes that the tires are the source of the noise, which I can believe, having had tires become loud before on other cars.

Suspension has all been replaced in the last few years, stock except for Bilstein HDs all around. Car was aligned 35k miles ago, after the suspension work was done. The basic question is: what is likely to have caused the tire wear I'm seeing? I'm going to pass by the alignment shop and see what they have to say, and maybe get it back on the rack to check where things are. This car seems to eat tires (though not with this sort of wear pattern, at least not that I've noticed), and I'm getting rather annoyed with having to replace them every few years.

Your cars recommended alignment settings may be great for performance driving but not for minimizing tire wear. (camber/toe) Have alignment checked and talk to alignment tech about optional alignment settings to minimize the wear. You will sacrifice handling for reduced tire wear.

You mention that you have snow tires.
Mount up the snows temporarily and see if the change in tires changes/eliminates the noise.

I too think possible that "performance alignment" is wearing tires quickly.

I had similar issues with our '09 Mazda 5. They are notorious for it. I finally got fed up with it destroying tires and got an alignment done by my local shop that is WAY outside factory specs (rear only, front factory spec is fine). It required me to install adjustable camber arms in the rear. Tire wear is now even across each tire, and near equal on all 4 corners. The dealer took it upon themselves to put it on the rack when it was in for some minor servicing and the new service manager threatened to not let it leave the shop as it was "dangerous" and "negligent" for another shop to align it to those specs.

It won't go back to that dealer again, ever. The previous service manager had praised me for finally solving the issue as they are aware of it, but not allowed to do what I did...Unfortunately he retired.

I was always under the impression that cupping or inconsistent wear around the circumference (as opposed to radial wear) was a sign of uncontrolled suspension motion, such as insufficient damping or bad / overcompliant bushings.

The rear ball joints are a common wear item on the e39. Make sure they are checked for play when checking alignment.

As mentioned, BMW has very aggressive alignment specs to optimize handling and disregard tire wear. If my customer isn't an aggressive driver I will set the alignment angle on the tamer side of specs (least amount of camber/toe).

Some cars also tend to run a lot of rear toe-in to keep the rear end stable when being driven hard. IIRC, the E46 is this way, so the E39 very well may be too. Running less toe in the rear will make it easier to step the tail out accidentally but should help tire wear significantly with no real handling sacrifice.

Duke wrote: I was always under the impression that cupping or inconsistent wear around the circumference (as opposed to radial wear) was a sign of uncontrolled suspension motion, such as insufficient damping or bad / overcompliant bushings.

That was/is always the first assumption. However, it is a combination of camber (usually negative) and toe in/out that causes to tire to scrub to the sideways and then pull back thus causing the cupping around the edge of the tire and making noise when the cupping becomes excessive.

I tried to talk to the guy who did the alignment, but he wasn't in the shop when I stopped by. When I do get to speak with him, I'll see if he's willing to dial in a less aggressive alignment to see if we can reduce the wear on the tires. I'll still be looking at a new set pretty soon, which means I'll be lucky to get 20k miles out of these. At that time I'll also be shopping less aggressive tires more oriented toward long life than anything else. It's a daily driver, and I have a toy (also riding on Sport Comp-2s) for when I want more grip.

And just to confirm for those who raised the question, all the bushings are in good shape, relatively new, and properly installed. This is an alignment and/or tire problem, I believe, not a suspension problem.

As I recall, the first Acura NSX customers were complaining about having to replace tires under 10,000 miles.

My tire wear is cause by an outside source.

The driver. he likes to take curves fast.