What Does 315/70R17 Actually Mean?

Let's break it down simply: The 315 means this tire has a tread width of 315 millimeters. The 70 is the aspect ratio, which means the sidewall height is 70% of that width. The "R" stands for Radial construction (the modern standard for safety and durability), and finally, the 17 indicates that this tire perfectly fits a 17-inch wheel.