Tires are made so when they're new, the outer layer is the softest(they have the best traction) as they wear down (and with age) they get harder and will produce more tire dust. That's why tires need to be changed even when they still have a little tread on them or if they have plenty of tread but are old. Tire makers know about this and are producing new tires that use layers of different rubber so that the when they wear down they don't have this problem and are still safe.

I have a DA Supercharged 1995 318ti with 215 45 17" Dunlop SP8000 tires. The rear tires a VERY worn (down to the wear bars) and I have a new set of Bridgestone RE730's on order.

: I took the car out for a spirited drive today and when I got back I noticed quite a bit of black dust on the rear bumper right behind the rear tires.

: I have H&R springs and Bilstein Sports on the car and I had the adjustable camber do dads installed in my car last fall. I think the guy who did the alignment is pretty good. I am not sure where this black dust came from (it definitely is not from the brakes). Is it possible that the tires are SO worn that they are creating this dust or could I have an alignment problem. The rear tires show the most wear right down the center with a little bit more on the inside edge (negative camber)than the outside. I think that they seem to have worn pretty evenly. My last set of tires showed MUCH more wear on the inside of the tires (before the adjustable camber do dads) plus I rotated them and did not have the SC installed yet.

: Any thoughts or comments would be GREATLY appreciated.

: Steve M.