Lower profile tire in the rear?

Maintenance/Repairs
1

A friend just picked up a 2010 Mercedes C300 from a used car dealer. I noticed that her car has 225/45 r17 in the front (proper recommended size for the car), but 225/40 r17 in the rear. What kind of problems would creep up because of this? I think she should return to the dealer and have them put the recommended tires all the way around.

2

The tire size in the rear should be 245/40R17. What is shown on the tire information label in the door jam?

3

Is it the AWD version? Then there could be damage to the AWD system. If RWD, the difference might set off the traction control/ABS improperly. Time to get all 4 tires the same size.

4

Look again at the rear tires to see if you may have mis read the 245.

On many cars with different fron/rear, the objective is to have a wider rear, but not shorter ( closer to the ground )
If hers is the sport trim the fronts are in fact the 225/45r17 and the rears, like neveada said, are 245…245/40r17
IF hers actually has the 225 on the rear …it’s those that are wrong.
BUT…
if hers has the luxury trim then all four should be the 225/45r17.
How to tell ?
The rim bead WIDTH…ie; how wide are the rims ? The type with the different rears truly has wider wheels back there with the fronts being slightly narrower.
The other has all four wheels the same , ergo, all four tires the same.

5

Great information, everyone. The best tip was to look at the information on the door pillar. (Thanks, Nevada-545). I’d never seen this before, but the front tires are supposed to be 225/45 and the rears are supposed to be 245/40. I misread the tire and thought both tires were 225s, but upon detailed inspection, they are correct. So I’ve made my friend stress out for no reason and I think I owe her a Coke. But we both learned something. Thanks, all!

6

Sounds like buying a new set of tires will involve shelling out some serious cash…But that’s one of the many joys of owning a Benz…

7

You were right to be concerned. Especially with newer cars with the high-tech suspension systems, it’s wise to stick with the exact tire size recommended by the manufacturer.