What is the difference between 285 65r18 tires and 275 65r18 tires?

Answer 1

The difference between a 285/65R18 and a 275/65R18 is height and width The first 3 digit number is the width measured in millimeters, 285 millimeters and 275 millimeters wide across the tread. The middle two digit number is an aspect ratio number or a percentage of the width. For example if the tread is 285 millimeters wide, than the aspect ratio of 65 is 185.25 millimeters. Meaning the side wall of the tire is 185.25 millimeters tall. 65 percent of 285 millimeters is 185.25 millimeters. So a 275 millimeter tire with the same aspect ratio of 65 will be a narrower and shorter tire, because 65 percent of 275 is less than 65 percent of 285. The R18 means that the tire is of radial construction and the tire is made to be mounted on a 18 inch wheel or rim.