I have 15mm H&R spacer kits all around my car, which brings my stock wheels from a 45 offset to a 30. Now, i'm looking at some wheels that are 42 offset but are 7.5" in width vs. 7" stock width. Keep in mind that my spacers will bring these 42 offset wheels to a 27! Alot of people when they upgrade to 18's go with 225/40-18. Now these tires are 0.5" taller overall then the stock 215/45-18. I'm deathly afraid of going with a 225 with a 27 offset cuz i think they'd rub like hell. (Dropped on tein S-tech and will be converting to coilovers soon) Now my question is, why don't people go with a 215/40-18 when they upgrade to an 18" rim because a 215/40 on an 18 that is 7.5" wide will only be 0.2" taller overall than the stock 215/45-17?

 

Oh i almost forgot to add. The 225/40's will stick out 6mm further out than the stock 17" tires, but the 215/40s will only stick out 2mm more.



Using this tire calculator:

http://www.rims-n-tires.com/rt_specs.jsp