Oct 23, 2020 · The diameter of the center circle of the rolling element of the bearing is 3150mm, the ball diameter is 75mm, the gear modulus m=20mm, the ring material is 50Mn, and the blank material is an internal tooth four-point contact ball manufactured in a normalized state. The swing bearing is expressed as 013.75. 3150.12.608 Full Ceramic Skate bearing that works in all skate applications like skateboard, inline skate, roller-blades, roller hockey, And even the 8mm quad rollers, Bearing can be used inline skate, rollerblade, roller hockey, Bearing can be used forpetitions or racings, You will need 8 bearings for skateboards and 16 for all other skate applications.A better bearing will keep you rolling longer, so you can put in less effort to cover the same amount of space. In the past bearings were actually put in by the skater with loose balls. This is very rare now. All ball bearings for roller skates made todaye put together, and have the same 5ponents. The 5ponents of a bearing: Shield:Single row radial ball bearings with flanges. True high precision bearings are not rmended for skates or fishing reels. High precision bearings are used in accurately balanced application such as spindles, gyros and medical equipment. If your application is not of a precision nature, standard bearings may be more suitable (and less expensive).