Tire size

[JohnnyMystic]

I just ordered some XXR 531 rims on black Friday and I'm not sure with the offset which size tires I should get? I got 18x8.5 Platinum 5-100/5-114.3 [+20mm] for the front and 18x11 Platinum 5-100/5-114.3 [+20mm] for the back. I was thinking 305/35/18 for the back but what size should I get for the front? And do I need to run a spacer in the back... if so, which size would look best?
Any help you guys could give me would be great!

 

[1BD9D7]

On the 8.5" wheel I would get a 255 or 275. The rear would be fine with a 305 but a 315 should fit perfect.

 

[digdugdaddy]

265/35 is what ran on my 8.5" BBS, just seem to fit better than 255/40