Is there a tire size that when put on a 17" wheel, would be the same width and diameter as a 255-70-18?

 

Probably the closest would be a 255/80/17. Same width and just a little taller. They come out to 33 inches. Plenty of options in this size too!

 

A 255/70-18 is 255mm wide (10.04 inches) with a total height of 32.06 inches theoretically.

32.06 - 17 inches = 15.06 inches of sidewall

15.06 / 2 = 7.53 inches on either side of your 17 inch rim

7.73/10.04 = 77%

So to be exact, you'll need a 255/77-17, which obviously is not available.

Probably get yourself a 255/75-17 or 265/75-17 and be slightly wider and higher.

 

255-75-17.......is the same as 255-70-18

use this site to calulate tire sizes

www.powerdog.com

 

255/75/17 is the same size, 32"x10", there's lots of them for sale on this forum.

first number is the tire width in milimeters, 25.4mm per inch therefore 255 is almost exactly 10 inches

second number is "aspect ratio" or what percentage of the width is the height. Just like on your TV, 4:3 old school or 16:9 flat panel. 70% of 255 is 7inches, 75% is 7.5 inches.

third number is wheel diameter in inches.

255/70/18 is the same size as 255/75/17

7+7+18 = 32 = 7.5+7.5+17

That all said, every manufacturer and every model from each manufacturer is a little different. Some measure widths and heights to different parts of the tire and the amount of air pressure can change the shape of the tire, too. But that's what the numbers signify.

 

Thanks for the responses.