I am currently running a set of Regas that are squared 17x8 +35. I just recently purchased a set of RG1's and they are squared as well 17x8.5 +37. My fenders are rolled flat, my quarters however are untouched. I want to run a 40 series for front and rear without stretch and I don't want to touch the quarters but if I have to I will.

I'm looking at 225/40 front and I have some idea as to what I want for the rears 235s possibly but I don't know the sidewall. I am still new to fitting wheels on these cars. Any help is appreciated.

 

225/40 is shorter than stock as is 235/40. Neither is a good tire choice. Roll the rear quarters and run proper size tires.

 

You should be able to run a 235/40 up front and a 245/40 in the rear. These are going to be the best stagger for your rim widths for fitment without stretch and have a chance at fitting with your current rolled fenders. I don’t know what your ride height is, but you will need some aggressive camber in -2.5/-3 arena front and rear.

 

So 245/40s in the rear?

 

Yep!

 

And roll your rear fenders and relocate the bumper tab.