rim width range

AviatorTim

I'm getting conflicting information from TireRack.com and the sales rep at my local wheel store.

According to TireRack, the rim width range of the front stock 225/50ZR18's (2009 370Z non-sport package) is 6-8"and the rim width range of the rear stock 245/45ZR18s is 7.5-9"

See specs here:
Yokohama ADVAN Sport

Their spec sheet seem to indicate the tires are already on the widest wheels they should be mounted on. Yet the sales rep told me I would have no problem putting the tires on 18x8.5 and 18x9.5 wheels I was looking at. Is he just lying to make a sale?

Imperial

They are both correct... The specifications you got from Tire Rack are the manufacturer's recommended rim width range but you may choose to stretch the tires beyond those specs at your own risk (potentially voiding any warranty the tires may come with) as many people do.

AviatorTim

I see. I think I will stay within the tire makers specs then. It would suck to have a blow out on day one of a brand new tire only to be told it wasn't covered because I didn't follow mounting instructions.

Also, isn't it true that as you approach the widest recommended width you are maximizing performance at the expense or ride comfort? I read something to that effect on another website. If that's true, I think that would make for a stiffer/harsher ride than the factory setup.

Tim