I am a bit new to all of this, my last vehicle was an '06 Jeep. Fitting large tires was easy. Lift 4.5 inches, 15x8 wheels with 5" backspacing, and 33x12.5" tires. No rubbing, beautiful.

This spring I traded it in on a 2011 MCS. Original tires wore out this month, so I got some stock sized blizzaks on the Cooper wheels for winter. Now I'm looking for my summer meats. I plan to autocross, as I used to in my Celica years ago... so I want wide rubber. From what I gather using the search function, a 225/45 tire will fit on a 17x7.5 wheel with no rubbing, despite the tire being a bit taller and much wider than stock. Does anyone know the optimal offset or offset range that can produce these results?

Second, I am seeing conflicting info in a few threads as to whether or not a 235/40 will rub on a 17x7.5, with a range of offsets being mentioned again. If there is a 235/40 on 17x7.5 + offset combo that is known to work with no rub or perhaps little rub with interior fender plastics at full compression, I would like to go that route, especially since it results in a nearly identical overall diameter as my currently stock sized 195/55R16s.

If it matters any, I am completely stock, no drop, and plan to stay that way for the foreseeable future. As for tires I am not decided, but I keep looking at Kumho Ecsta XS, Dunlop Star Spec, and Sumitomo HTR Z's.

So to sum up...
Does anybody know the acceptable offset range for a 225/45 on a 17x7.5?
Does anybody know the acceptable offset for a 235/40 on a 17x7.5, if possible at all?

 

I did the 235/40 on a 17x8 ET42 - not sure if this helps, as you wish to do 7.5's.