What Does 310/35R12 Actually Mean?

Let's break it down simply: The 310 means this tire has a tread width of 310 millimeters. The 35 is the aspect ratio, which means the sidewall height is 35% of that width. The "R" stands for Radial construction (the modern standard for safety and durability), and finally, the 12 indicates that this tire perfectly fits a 12-inch wheel.