. Its dimensions are 110/90-13, which means it has a width of 110mm, a profile of 90, and can be mounted on a rim with a diameter of 13". The profile of the tires, which refers to the height of the tire's sidewall, is always expressed as a clean number without a unit of measurement as it is a percentage of the width. For example, a tire with a size of 100/90 has a width of 100mm and a profile of 90, which means it has a profile of 100 x 0.90 = 90mm. See Description & Specifications