Im thinking cuz of the upgraded wheels.....I have the AMG 18x8 and 18x8.5 staggered wheel setup...so yes, my rear tires are wider than the fronts.

 

Really ? I gotta measure this lol
Thanks for bringing up this

 

So I guess tire rotation is out of the question?

 

The SLKs have this tyre rotation problem due to larger rears - If you get non directional tyres, you can swap left to right without dismounting from the rims

Oberoi

 

If you have a 4Matic, then it is required to have 4 same size tires.

 

My E class coupe w RWD has staggered front and rears and my C has staggered sizes with 4 matic. Not sure of the need for same size with 4 matics??

 

My E550 4matic has the same size front and back.