I want to put the widest rear tires possible on my 2010 RS, I got the table below from an earlier post, but I dont know how wide my rims are. Currently I have 275/40 ZR20's. Anyone know how big I can go? And is measuring the rim width as simple as laying a tape measure across the inside of it? Thanks

245/45-20 = 28.7" tall, 8.0-8.5 wheel
255/45-20 = 29.0" tall, 8.0-8.5 wheel
265/40-20 = 28.4" tall, 8.5-9.0 wheel
275/40-20 = 28.7" tall, 9.0-9.5 wheel
285/40-20 = 28.9" tall, 9.0-10.0 wheel
295/35-20 = 28.1" tall, 9.5-10.5 wheel
305/35-20 = 28.4" tall, 10.0-10.5 wheel
315/35-20 = 28.7" tall, 10.5-11.0 wheel

 

What did you end up going with?

 

305s - Antares Majoris. I was hoping they were a little bigger, but oh well, selling the car now.