staggered

Hi all I recently purchased a C Class 2014 (W205) Bluetec Sport Premium. I've just noticed that the tyre sizes on the front are the same as on the back?! They're both 225/50 17 Y. I thought rear wheel drive vehicles had bigger/wider tyres on the back as was evident in my last C Class...

I've been holding off until the good weather landed to get my wheels either refurbished or replaced. I just found an almost new OEM set of alloys from a W205 for sale that I'm hoping will fit my W204 C350 D. Their sizes are: Front wheels ET44, 7.5J Part number A2054019500 Rear wheels ET49...