I'm new to the forum, sorry if this is a duplicate, I promise I searched!

I have a 2010 G37 Journey RWD and I need new rear tires. It has the stock 225/50/18 Michelin Primacy tires and I want to go wider and stickier. I "think" my wheels are 18x8 and I could fit a 245/45/18 but wanted to ask the experts first. I'm pretty sure the width will fit on the wheel and the height isn't too different, but I'm not certain. Thanks for reading.

I'm thinking of getting these:
http://www.tirerack.com/tires/tires....omCompare1=yes

 

You'll be fine w/ that size, although I'd replace the fronts w/ the same tires in the near future since the rears will be much more performance oriented. Oh, and welcome to the site!