W205 find correct rear tyre size (225/50/r17 or 245/45/r17)

[PaulOliveira]

I'm looking to replace all 4 typres on a c-class W205 sport premium from 11/2014
I bought the car used in 2017 (mercedes used approved) with all 4 tyres: 225/50/r17

On the ats euro master website the recommendation based on the registration plate is:
Front: 225/50/r17 Rear: 245/45/r17

On this website, it presents two possible options:

Mercedes-Benz Fitting Chart and Wheel Fitment Guide | Alloy Wheels Direct

Comprehensive wheel fitting chart and guide for Mercedes. Information on tyre and wheel sizes, offsets and PCDs. Find out which wheels will fit your vehicle

www.alloywheelsdirect.net

Front and Rear: 17x7 48.5 225/50/r17
or
Front 17x7 48.5 225/50/r17 and Rear 17x8 54 245/45R17

It seems that in order to support the 245/45R17 in the rear, the rims need to be 17x8.

Is there a way to identify if the rear rims are 17.8 without taking the tyre out?
What was the original (new car) setup on the W205 sport premium in the rear? 225/50/r17 or 245/45/r17 ?

 

[whitenemesis]

Rim size info will be embossed on the rear face of the spokes.
Quick and dirty way just use a steel rule poked through the rim and measure.? 1 inch is quite a difference (Oh, matron!! )

 

[Riva811]

The tyre size compatible with your vehicle should be printed on the fuel tank hatch

 

[whitenemesis]

The tyre size compatible with your vehicle should be printed on the fuel tank hatch

But may not correspond to that actually fitted to the vehicle now..

 

[raspy]

@PaulOliveira I have a 2015 C350e Sport Premium Plus with 17 inch wheels. The tyres fitted to my car from new are the same as what ATS Euromaster website suggested for your car;

Front: 225/50/r17 Rear: 245/45/r17

Maybe take a look at the datacard for your car by entering your VIN online and seeing what wheel/tyre combo was originally defined for your car when new? I think you should be able to get that info with a VIN decoder

 

[E55BOF]

The VIN will tell you what wheel sizes were fitted from new, but they could have been changed since. As per WhiteNemesis's post, just measure the rears.