OK, I no nothing about tire sizes, but my friend is going give me a set of Sumitomo HTRZ II and a set of Yokohama AVS ES100. But they are 255/40 zr 17!
Can I mount those on my stock 17 x 7.5 inch rims?

I highly doubt u can fit those.......especially on the stock rims

a 255 tire is too wide I believe. The sidewall will be very big as well.

I doubt it would fit, especially your on Hotchkis.

NO, they wont fit.

225 is the widest a 7" rim will take.

The stock rims are 7.5, not 7, but I still dont' think their going to fit. Just looking at them next to my car, they are WIDE!
CRAP! and they were free too!
Oh well. He said he has a set of Pirellis that are 235. I might be able to get those on. Damn Porche tires!

no they are 7"... 17" x 7"

definately 7" not 7.5" lol

Double crap. If they'r 7", then I don't even think the 235 are going to work.

yea, 235 will still be too wide I believe.

I've heard others here say they run 235's on their stock wheels, so I think it's possible, just not recemmended. And most definitely not if you're lowered.

You should sell them and buy 225's

Looks like I'm gonna have to.
Thanks for all the input.

I have 225's on my car. The place that mounted them were skeptical enough putting that size on. If I took them a 235 by law they wouldn't put them on.

Im runnin 235's atm, they work... sorta... they rub around corners when I have passengers in the back seat, which is never, so it's not a prob. Gonna go 225 next time...

But according to your profile, you have 18" Konig Unknown, not the stock rims.

Running one-size up on tires is the most you should go.
1) Safety
2) Profile.

If you go up too much, the profile of the tire - the one that real life engineers designed - will be improper.
It is dangerous and wear will be bad on the center of the tires.

Bottom line, don't do it.