I'm looking at purchasing a used 2011 C300 from a dealer. It appears to be in great shape overall, but I'm concerned about the new tires they've mounted.
Front and Rear tires are both 245/40 R17.
The back tires fit their wheels/rims differently than the front tires. Specifically, either the tires or the wheels are of differing widths. The rear tires are Zeetex (had never heard of them until I did a web search) and the fronts are a different manufacturer.
The wheels are OE 5-spoke.

When I look it up online, it appears that the 2011 C300 was originally shod with 225/45 R17's in the front and 245/40's in the rear.

Are the front and rear rims different widths or the same?

 

Some have staggered wheel fitment which means the front and rear rim widths are different. Example is my stock 17's are 7.5" wide for front and 8.5" wide for the rear.

It's very possible that car has staggered fitment and someone just installed the 245/40-17 tires on instead of the 225/45 - 17's on the front.

Makes you have to guess which wheel is suppose to be where it is or not though. They probably did it for rotation purposes maybe to cheap skate on tires.

 

Thank you for info, Catmandoob.
After talking with the dealer again (by phone), I was incorrect about front tire sizes.. they are 225/45 R17.
So I'm guessing you're correct about the wheel widths differing from front to rear. If the 245/40's are indeed 20mm wider than the 225's, I'd think the wheel/tire fitment would look about the same.
But it's easy to tell (looking at the tires/wheels) that the front tire's sidewall width extends out past the rim slightly. On the rear, the rims actually extend out more than the sidewalls of its (245/40) tires. Looks pretty crappy to me...
Definitely don't want to be brushing the curb when parking the thing because it will scrape those back rims!
Maybe the Zeetex manufacturer (UAE) measures their tires differently...

 

That sidewall difference you see could just be a difference in the brand of tires. The best way to avoid the wheels getting scraped is to not hit curbs in the first place.

By the way, I used to own a 1991 Alfa 164S way back when. Loved that car. Just had such a connected mechanical feel to it when driving. Engine also had those cool looking chrome intake runners.

 

It's probably because if they are from different manufacturers the front tire brand has the common bead wall lip to help protect the wheel where it hangs over just a bit.

Without that protective lip you would see more of the wheel sticking out.