1st Gen R53 Cooper S Rear tires wearing on inside edge

How frequently have you been rotating the tires? I had not been good about this in the past (did not have time) until I got my Mini. Now I make time, and tires last considerably longer.

 

The problem with the 2003 Minis is that the rear camber cannot be adjusted without installing aftermarket lower control arms.

The rear alignment spec allows all the way to -2.6 degrees of camber and 0.53 degrees of toe-in. If you car is near these alignment limits the alignment will still be considered "in spec" but it will wear the inside edge of the tires.

The rear toe is adjustable and as others have suggested there is usually too much toe-in on the rear which causes the tire to scrap across the inside edge of the tire (with negative camber), wearing the tire quickly. I would suggest an alignment with close to 0 degrees of rear toe.

Some alignment shops will say that the rear toe cannot be adjusted without a special BMW tool but that is not the case. It is just a little more time consuming to adjust the rear toe without the BMW tool.

Low tires pressures will also accelerate the wear.

 

I'm pretty sure you mean like this....



My car has a 22mm rear swaybar which stiffens the rear suspension enough that the inside edge will have more weight on it while driving straight. If cornering hard, more of the tire will be in contact with the road. I do a full wheel alignment every now and again and I have concluded this is normal for the MINIs.

If using regular (non-runflat) tires, you wear down the inside edge and change tires. If using runflat tires, be careful. My OEM Pirelli Euphorias had the inside sidewall start to separate from the tire where the tire started to crack and separate at the first tread bar.

To prolong and wear the tires more evenly, you can rotate your tires front to rear. I do that now when I do my spring switch over from winter tires. I have the tires marked when storing over the winter and mount the rears on the front and the front tires to the rear. It does compromise traction a bit, but does prolong the life of the tires an extra year or two.


Alternatively, it means you are not cornering hard enough. ; )

 

Good picture, looks like your inside is feathering, that's an alignment issue. Two issues here camber & feathering from too much toe-in. Although it may be the picture is fooling me. Can't run my hand over the tire & tell.

FWIW I do not believe that your sway bar is adding spring rate to your suspension when driving straight. It only comes into play while cornering.

 

I stand corrected on the swaybar/spring rate effect.
However, I regularly get wheel alignments done on my MINI and the dealer blames the tires and the tire company blames the alignment. So, I'm not sure who to believe.

 

The dealer is not going to give you a good alignment. There is too much slop in their specs. Find a place that can do a custom alignment to your spec's.

I'd side with the tire company. Your dealer is giving you a sloppy alignment.

 

^ This.

The "specs" for MINI factory alignment suck, quite frankly.

Pretty much true of all standard alignments, because the manufacturers spec in a significant amount of understeer because they consider that safer than the possibility of "snap" understeer (rear end coming around).

So then we all go out and get stiffer swaybars, to add more understeer and make the car more neutral. If you're really serious about it, you add camber plates up front to really make the car neutral.

There's nothing sacred about the factory-spec rear camber or toe. In truth, most MINIs have too much rear negative camber, too little front negative camber, and too much toe all around.