stock rim size
 

anyone know what size the stock rims are on a 99 gt vert with 17" wheels? they 17x8 or 17x9?

17x8.

and what is the biggest tire i can run front and back :)

Depends on the tire. But you wouldn't want to go any bigger than a 275.

like 275/40/17 all around or what

thinking maybe nitto 555

Yea run a 275/40 out back with some wheel spacers and a 255/40 up front. Nittos would be fine, they run a little on the small side anyways.

You'll want skinnier tires in the front like a 255. Its been proven that its easier to regain control of a RWD car that has skinnier tires up front. Thats why F1, indy and such have different size tires front and rear.

And tire brand is preference but if you live in an area that gets rain then definitely get a tire that is good for that type of weather. When I used to post more regularly, there was always 1 or 2 mustangs wrecked every week because someone lost control in the rain. So that means DONT RUN DRAG RADIALS FOR EVERYDAY DRIVING!

And here's kind of a surprising statistic, 75% of ALL car accidents happen in the rain. So choose your tires wisely.
-P.

yeah i feel that in the rain. i hate the ones i have now, my mom put them on. crap... im going to be living in texas so not much rain lol

but when it rains it pours in TX...in the southwestern part anyways

you dont need wheel spacers to run a 275 out back, i normally run a 315 on my 99 gt out back with a 245 in the front but i have bolted on my 03 cobras 17x9 with 275 all the way around with no probs. i didnt like running that 275 in the front though. the road felt bumpier with the wide tire up front.