Interesting - the winter tyres I picked up (on the same rims) are 285 at the back, which matches the summer tyres I took off. Looks like my rears may have been over-specified.
AMGeed is right on the OEM winter set up at 255 all round. The standard 19” (summer wheel/tyre) is a 19x10” rear (I think) and runs the 285. This wheel is the same design as the 9.5” used for the factory winter spec. Therefore, if you have a 285 rear with a winter tyre I guess it depends on what rear wheel rim width you have with it.Interesting - the winter tyres I picked up (on the same rims) are 285 at the back, which matches the summer tyres I took off. Looks like my rears may have been over-specified.
The 255 winter 19" on the CLS63S/E63 W212 drops the rear rim size to 9.5" if you buy the complete wheel/tyre package. I don't think either car would take a 255 on the standard 10" rear or wider, as the rears are pretty stretched on the 9.5 " rim with the 255. but I'm no tyre fitting expert. If you're fitting a winter to the standard (summer) width wheel I assume you'll need to use the same width winter tyre as the summer tyre.I think I need to check this. I have 285’s on my 911 (10” rim) and they look quite big for the rim, whereas the 285 on the E63 looks really stretched- I’d be amazed if a 255 would go on there. If you asked me to guess the E63 rim width I’d put it at 11.5” from how a 285 sits.