Bearing spacers why do we need them ???
Bearing spacers are extremely important to take side load off your bearings and at the same time allowing you to quickly and properly tighten the wheel nuts to a correct firm tension, and still maintaining 100% a free-spinning roll with no axle chatter.
We do see many customers who have been misled thinking that their wheels should spin for an exact amount of minutes and seconds and to achieve this it would be ok to have loose wheel nuts no spacers.
This, in fact, will cause premature wear, bearing chatter, or bearing lock possible damage to the axles, plus your wheels could vibrate off possibly causing injury to the user,
All bearings fit into a recess and the gap between the two recess points this is your exact spacer width thus allowing you to tighten the retaining nut nice and firm putting absolutely no pressure on the side of the bearings allowing the bearing 100% free spinning.
One thing to remember new bearings that are pre-lubricated will take a few days to run freely, the higher the abec the higher tolerances as in smoothness and firmness of the bearing, plus the higher the abec does not mean will spin faster, in fact, abec one or abec eleven can all do the same revolutions per minute but the higher abec due to there higher quality will run cooler and smoother as the machining tolerances are more exact.
For any more feedback contact
Ed @ amproskates.com.au over 45 years of Mechanical engineering experience.