because bearings are built a certain way. Yes, it is important to have them for dialedness^ but thats not the issue. Bearings are built like this (o) if the small o in the middle gets pushed to the left or the right(by your axle being tight), the ball bearings get offplaced and dont roll like theyre supposed to. So, If you want your scooter to be fast and dialed, put the bearing spacers in