Hmm, learn something new every day. I was in the process of replying to your post, Junk. I was going to say that changing the width of the tire would not make any difference in the revolutions per mile. I wanted to make sure I was right though, before I put my foot in my mouth, so I decided to do my homework. Turns out that changing the width of the tire does affect the number of revolutions per mile. All this time I thought the 275/40 part of the tire label was done that way for looks, who knew it really was a ratio! The P275/40ZR17 tire is actually 8mm shorter than the P285/40ZR17!
The
Tire Rack has a really good article explaining how tires are labeled.
I'll never doubt you again, Junk. :BOW
Jason