I have a 2014 c250 Sport currently with 245/40/17 rear tires, they are hankook tires and since the passenger rear got a puncture last year it was replaced with an identical unit, but the driver rear stayed the same, one year later passenger rear is still good but driver rear needs replacement, In the garage I have 2 spare 235/50/17 tires off a porsche boxster, I was wondering If i can use those on the benz without any issues?? If so that is great, if not why not and also weather If I have to purchase tires can I get away with only replacing the worn or is it time for a fresh rear set

 

Anything?

 

Thought I had replied. Guess I didn't hit submit.

The car requires tires with at least 91 load rating. The 235/50/17 Boxster tires have a load rating 96. Okay there. 8½ inch is the maximum rim width for that size tire. Okay with stock rim size.

The Boxster tires are a bit taller than the 245/40/17s. You will be going 69 MPH when the speedometer says 65.

I think the Boxster tires are going to look a bit strange replacing those low profiles.

I can’t comment on the traction and handling changes, if any, so be your own guide and be extra careful for a few thousand miles.

Personally, I never run a worn tire on the same axle as a new one except in an emergency. I’m pretty sure W204 has a 3 channel ABS system. I think both rear wheels are on the same ABS channel, so emergency braking performance could be compromised.