uneven tire wear
 

i have 16000 miles on my 20' dunlop rear tire and i think i can get another 5000 from it but my concern is the inner tread is pretty worn out. anybody here experience this? do i need an alignment? i just replace my front tire and the tire wear is pretty even. thanks

Get down low and look at any X5 from the rear. The rear squats down, which puts most of the load (i.e. wear) on the inside of the rear tires. The wider the tire the greater the difference between inside and outside. This wear difference is also increased when you carry a heavy load (or tow a trailer).

OTOH the fronts get most of their wear on the outside. This wear difference is increased if you do a lot of short radius turns on pretty rough surfaces (e.g. parking garage ramps, circular driveways, etc). It becomes even more noticeable when you always make short radius turns in only one direction (e.g. if you park on the top floor of a tall parking garage which has ramps that force you to always make sharp counter clockwise turns).

FWIW after seeing how much average tread was left when we had to replace our first set of tires on our 2001 X5, I began swapping tires front to rear every 5000 mi or so to even out this difference in wear. Yes I know BMW does not recommend this. But it works!

Funf Dreisig

This is typical for BMW setups. Rear tires are set up to sit on the inside of the tire to help out in the handling department. Just the price to pay for better grip. The rears will wear faster than the fronts in general and the insides of the rears are the first part to go.

good time to ask this then - would it be ok to swap in new rears without fronts? My remaining vibration in the rear is likely caused by an out-of-round tire on the right rear. I've got 9k miles on all 4. Would it be alright to swap both those rears out, running old / new like that? They will be Proxes ST II in the rear and ST in the front (discontinued).

I ran old and new pairs on our 2001 X5 for most of it's +90k life. Luckily Michelin kept making the exact model that whole time so I never had to face that issue.

Despite recommendations I've read on XS forums, I like to put the new pair on the front of an X5. The front does most of the cornering and braking (just look at the size of the brake discs). On AWD vehicles the rears are actually the least "used", unless you 'floor it' a lot. What causes the rear tires to wear out faster is the strong negative camber (for better cornering) that produces such much wear on the inside.

Of course you need to take it easy while you break in new tires whether you are replacing all four or just two.

Funf Dreisig