will a 275 size tire fit on a 9 inch wide wheel? or will i need 9.5?

 

275/40/17 will work fine.

 

thanks. should i run 18x9.5 instead? i have the option of either and i know the 17s are lighter for track. but what do u think?

 

You could go 17x9.5 and run a 45 series tire. It is just as tall as an 275/35/18 and the tires cost $50 less each on average. The rims are lighter and cheaper. I've done both. (Both are in my garage) If you plan on running big brakes, just make sure you get ones that will work with a 17" wheel (Wilwoods).