The first number is the tire’s width in millimeters; the second represents the tire’s aspect ratio, which describes the tire’s sidewall height as a percentage of its width. In this case we have a tire that’s 130mm wide and 70mm high. R means this tire’s radial, and 17 tells us it fits a 17-inch rim. MC means it’s a motorcycle tire, while 62 is the load rating index, or the maximum amount of weight the tire can carry at maximum inflation. This may also be expressed elsewhere on the sidewall as a letter or spelled out along with the maximum tire pressure. Don’t confuse maximum tire pressure with the motorcycle manufacturer’s recommended tire pressure. The maximum is the pressure the tire can safely hold, not the pressure you should be riding with under everyday circumstances. H is the tire’s speed rating, an H-rated tire being safe at a sustained 130 mph. You’ll also find either tube-type or tubeless stamped somewhere to let you know if you need a tube.