Tire fitment

Up sizing:

There are two possible areas where upsizing may lead to rubbing. First is in the over all diameter of the new tires. In your case the closest --so close as to be almost no difference at all-- comes from the 235/45 R18 tires.

But --and this is where the other factor comes into play-- this tire is considerable WIDER than your original 215 tire. It is, in fact, 20mm wider. This is getting close to one inch wider and it could be a cause for concern. The best bet is to try a test fitting by mounting one tire in the area where there is the least clearance. Try a front wheel where you can turn it the maximum distance left and right and if there is no rubbing then you're likely going to alright. If you find minor rubbing you may want to choose the 225/45 R18 tire which is just a wee bit smaller in diameter but still wider.