Hi, in my 54,e320 CDI estate,I am experiencing crabbing from the backend when hitting holes in the road it's only momentary but annoying, it's air suspension on the back only, I've also noticed just today that the outer 40 mm on the offside tyre is bald, the other side is not as bad but getting there, no tread wear anywhere else, would all that have anything to do with the change of wheels from standard size to 245'45'17s on a 20 mm spacer ? Have also got some vibration which rises and falls mainly at high speed !!. Incidentally wheels were all balanced etc when new tyres were fitted 6 months ago. Any suggestions would be most appreciated. Thanks.