What is the widest 17 or 18 inch wheel and tire I can fit on my car without having to roll the fenders. What offset do I need for the wheel?

What I want is to fill up the wheel wells without having my tires stickout from under the wheel wells? I know nothing about wheels at all is the only reason I ask.

Thanks

 

All the 4th Gens are pretty much the same in this respect. Typical answer is 17x9.5" 45 to 56mm offset in the front, with 275/40 or 285/40 tires. 17x11 50mm offset in the back, with 315/35 tires. Ken Mook ("kmook") ran 335's in the back, but it must have been a tight fit. 18's would be the same as far as width and offset.... just needing "35" aspect ratio tires in the front and "30" in the back.

 

Thanks for the input. That is exactly what I was needing.