I tried looking this up but i think i know the size of tire i can run but i was just making sure before i order them…
i have a 17 X 8.5 rim and the tires on there currently are 245/45/17. what is the biggest size that i can run safely. I was looking at 255/40/17 because i can get a cheap price but can i go any bigger?
here:
This website kicks SO MUCH ASS when it comes to aftermarker tire and wheel sizing.
you can compare up to 4 tire sizes, or stock +3 others to see what percentage the ratio is off by
275/40/17! 
will 275/40/17 fit ? the rims a c 5 corvette rim
they fit on my 17x8.5’s
I had 285/40r17s on my 17x8s and I’ve even seen 315/35r17s on 17x9s.
275/40r17s will be totally fine, a little bit of bulge but nothing crazy.
ya i want the tires to stick out out a little bit more because the 245 are just about flush with the rim… i think 275’s will be ordered in the next week or so and off to swerve