Speed Demons ABEC-5 Red Skate Bearings. Speed Demons Bearings are made to mount your wheels to the axle. Keeping your bearings clean and in good condition is essential to a fast and smooth ride. Make it easy on yourself by starting with high-quality Speed Demons Bearings. Sold in sets of 8 bearings to complete four skateboard wheels for one skateboard, two bearings mount each skateboard wheel to its truck axle. The industry standard size is 608 with an 8 mm bore, a 22 mm outer diameter and a width of 7mm. Note: All skateboard bearings are the same size. These bearings will fit any skateboard.