So many numbers! Why? What do they mean? This article will explain how to read our tire sizes, and what each of the numbers in our sizes represent. The bottom line is, I like to be precise. The more precise I can be, the better the tire will fit. Better fit equals ease of use and better performance.

Let’s take a look at an example – 205 x 85 x 134 / 50 – 14

The numbers are measurements in tenths of millimeters, which I use to avoid using decimals (which would make the numbers even longer). Those numbers are in two groups separated by a slash “/”. The numbers to the left of the slash – describe the size of the tire. The numbers on the right of the slash, describe the center channel (rib space) of the tire – typical on most slot car wheels.

So in our example, first number (205) is the diameter of the tire when mounted on the wheel, the second number (85) is the width of the wheel, and the third number (134) is the diameter of the wheel off the rib (where the tire sidewall touches the wheel). In this example, the tire would be 20.5mm in diameter, 8.5mm wide, and fit on a 13.4mm wheel. Now for the rib channel measurements – the numbers to the right of the slash. The 50 represents the rib/channel width, while the 14 is the rib/channel height (again – in 10ths of a millimeter), so the rib is 5.0mm wide, and 1.4mm tall.