So I am trying to purchase some wheels and tires for my new g37x I just got. I have some wheels from tire rack that I think would look really nice on my pearl white car. It says they are 20x8.5 but that isn't very wide, is it?

Enkei Performance Lusso Black w/Mach Lip

 

The stock wheels are 18x8, so no that isn't very wide compared to what you've got right now. That said, you could fit a 245 (maybe 255 even) tire on there which is a good deal wider than stock.

 

If they are only 8.5, how am I able to fit tires of 245 dimensions on my car?

 

225s are typically mounted on 7.5-8" rims, 245s on 8-9" rims, so your 8.5" width is just right for 245s. FWIW I've got 245s on my 8.5x20 fronts, perfect fit

 

Thank you for clearing that up for me!