Hi, Can anyone tell me if I can down size my wheels from 19" to 18" on my 2010 911 C4S cabriolet? I would want to retain same width that I have currently but increase sidewall from 35 to next size up. Thanks, Steve

 

Here's what your owner's manual shows -

 

Why do you want to do that? Your ride isn't going to be that much different. Tires will be cheaper definitely. If you don't like your current tires, try a different brand. It makes a world of difference. Unless you go to 17", there isn't that much difference between 18 and 19.

 

Thanks guys between the two answers I am guessing I can't downsize enough to compensate for poor road conditions with thicker sidewall. I will stick with the 19". The left front rim seems to have an unrepairable crack that stays "fixed" for about 8 weeks and then slowly starts to leak. I wanted to check my options before I buy the replacement rim. Steve

 

If road conditions are your problem then a switch to 18s might get the little extra you need. You could touch base with Tire Rack for some help/possible purchase. Although it looks like you might be more than a few miles away.

 

As long as the new 18 inch wheels

Clear the brakes, retain tpms and are the proper offsets it should work. New tire sizes should be around 235/40/18 295/35/18 (not 100% if they make these sizes however. With that said it will make a quite a difference in overall ride quality.

 

Post#2 has the OEM sizes.

 

i stand corrected! thank you!

lol my guesses re sizes were correct!