rear tires issue

hi!
6 month ago i`ve got a 2000 bmw 323i.....tires on it seemed to be new.....but after like a few thousand km`s......i noticed that the inner sides of the rear tires have worn out(alot) a guy in the tire store said that under inflation might be the reason.....so i`ve got brand new Fuzion ZRI......but after like 3k i`ve noticed some kind of cracks(on the insides again),but this time tires were not underinflated for sure......
does anyone know what that might be???
p.s: it`s a rear wheel drive,and no I dont spin tires.....
thatnx guys

One sided tire wear is usually excessive camber.

BMW's are kind of noted for using more rear camber than the average. That improves the cornering capability, but the downside is one sided tire wear.

BMW also doesn't recommend tire rotation under the mistaken belief that a tire takes a "set" and "likes" being in the same position. This would be true if the only concern was cornering, but if tire wear is considered, rotation is a must. BTW none of the tire manufacturers agrees with BMW on this issue.

Hope this helps.

r u trying to say that its normal that they started cracking after like 3,000kms ??????

Actually, I was pointing out what would cause one sided wear and hoping you'd pick up that camber might be the cause of the cracking.

Actually, I was pointing out what would cause one sided wear and hoping you'd pick up that camber might be the cause of the cracking.
thanx alot man