I tried to do that and they wouldn't mount anything over 255 on my 8" rim. They said their insurance said it was a no no and they told me I would have to get a wider rim. Since I had already dropped the change for the rims...I wasn't about to go looking for wider ones. I did like the look of my 305/60/15s but those were widened 15x10 Police Rims on the rear of my 70 Charger...but c'est la vie