Dude

i have a C230 and have 225-50-17 inch tires on it and they dont rub...but my car is not a C36 either my rims r 17x7.5 front / 17x 8 rear...not sure if it will help u out but the wider tires make it ride smoother on the eway

 

it will most likely make your speedo read slow and may mess up your ASR functions.

Why would you do want to go wider? Traction issues?

 

...

Why would you do want to go wider? Traction issues?

No traction issues. I have some 255/40/17 on the shelf from my Porsche 928 that I would like to reuse for the C36.

 

Yes you can fit them and if your car is not too low you wont have rubbing, i have that set up. and it wont make your speedo read off since the speed is read from the front right speed sensor. nor will the ASR act up for with 255/40/17 and 225/45/17 front there wont be much of diameter differance to cause any issues.

 

Your cruise control will not work!
I ran 255/40/17's in the rear last year. It looked alright, but I was pissed because
my cruise control stopped working after 75km. And sometimes didn't work at all. If
want to go wider, go with 255/35/17's...............

"just my opinion"!

 

i would have to say yes ur cruise will stop working, on my car its above abt 105km/h

 

Some people don't care about the cruise control, but I use mine all the time.
Especially on the freeway, when I'm doing approx. 180km/hr (just joking....)..lol
Another thing is a 255 tire will look bulky on a 8.5" rim (bulky, bigger sidewall).....

 

I just installed them. But I will need to check concerning the cruise control...

 

Any updates to this? Does the cruise control really get messed up when having 255/40 R17s instead of 245/40 R17 on the rears? Sounds weird..

 

I can vouch that, YES, it will mess up your cruise. The system checks the right front speed sensor and compares the value of rear wheels rpm. It doesn't match program values and the ecu and the esp system thinks you're losing traction (actually the rear wheel speed sensors sense the rear going slower than the front and shuts down the cruise control). Eventually it will throw out an OBDII fault. I noticed it the day I put on 255x40zr17's (and it doesn't look bulky) on my 2003 c320 with AMG rims_ 17 x 8.5" rear & 17 x 7" front