what happened to my rear tires? (long)

[dsbeaupre]

I just swapped out my snow tires, because my rear tires are nearly bald. My question is why are they so badly worn.

Here's the info - I have a 98 528i Sport. I bought used Pirelli 210 snow tires (225/55-16) mounted on Borbet wheels at the beginning of the winter. The front pair looked new, and the rears did look unevenly worn - they were worn much more in the middle than at the sides, but still had plenty of tread to get me through the winter, I thought. Well, after the last two storms here I knew I had to get the rear tires swapped out - they are almost completely bald through the middle, but still have decent tread on the shoulders. Half way through the winter I tried changing the pressure, they were at 35, down to 29, to try flattening the sides out. It looked like they had been overinflated at one point, hence wearing only the middle. Obviously, I will have to replace these two for next winter, but the fronts still look new.

So I've got my all season 17" tires back on. Should I be expecting this same kind of wear on the rear pair?

Does this occur because of the traction control? I didn't do any 'hard' driving, and certainly no burnouts - just a bunch of spinning on the snow and ice.

[·clyde·]

The wea sounds like overinflation, but 35psi isn't excessively high. The wear pattern could have been excabberated by the tread compound as most snow tires have different compounds in different parts of the tread (center to sides and from carcass to full tread). Generally, the closer to the carcass, the harder the compound to maintain tread life even if it is not as sticky as the soft stuff when new. Same kind of thing for the sides to the center in the tread. Considering that the tires were already showing wear int he center when you bought them indicates to me that there wasn't much you could have done about it (although lower the pressures may have bought you a few extra miles). I wouldn't expect the a/s to wear the same way.

[dsbeaupre]

Thanks, I was just getting worried that I'd be going through a lot of tires on this car (I've only had it six months). I had figured that it was because of the traction control, but I guess its not.

I'll definitely be keeping an eye on all the tires. My 17's had 37 psi in them when I bought the car - the dealer had just put the new wheels and tires on, so I've left them at 37. Only about 5000 miles on them so far (from last fall) only 50 more on them for today.