The diameter of these tires is 68mm. The original tires are also 68mm. If you use 70mm tires, they may slightly interfere with the corners of the bolts on the skateboard side for the Ripstik Deluxe Mini. Depending on the angle of the bolts, there may be no interference, but if there is interference, the tires will not rotate smoothly. With these 68mm tires, which are the same as the original ones, you don't have to worry about interference. ◆ This is a set of 3 new tires. As children become more skilled at riding, the rear wheels tend to wear out quickly, and even if you replace them with new ones, they often need to be replaced again in a short period. Therefore, we offer a set of 3, including a spare for the next replacement. ◆ If you need 4 or more, please consult the price in the comment section. Up to 6 can be shipped together. ◆ These are replacement wheels (tires) for the 【Ripstik Deluxe Mini】 from (stock company) Rangs Japan, the best-selling brand of Brave Boards (caster boards). ◆ Please check your child's skateboard (Brave Board) and if it says "RIPSTIK dlx mini," these tires will fit. ◆ These tires come with bearings and bearing spacers installed. They have the same configuration as the original replacement tires. (A bearing spacer is a spacer inserted between the bearings inside the tire. The tire will rotate even without a bearing spacer, but it is included in the original tires, so it's better to have it for safety. Most of the cheaper tires sold elsewhere do not have bearing spacers.) Tire size: 68mm x 24mm (same as original) Tire hardness: 85A Bearings: ABEC-7 (same as original) ◆ We will ship in simple packaging.