Fierce - Hub Measurement Jig
(Currently available in red - e-mail to order other colours)
Every wheel hub, from every manufacturer, is different and your bearings are only as good as your spacers. The job of the spacer is to push the bearings apart to allow for better free spin.
Because the tolerances are so tight, and every wheel brand or bearing brand has slightly different dimensions the Fierce Hub Measurement Gauge will give an exact spacer measurement on each wheel to the .000 of a mm to ensure the correct fit.
The spin you get from your best bearings is dependent on the wheel assembly giving them an evenly-loaded environment.
If you notice a clicking sound as you skate, this is indicative of a spacer that is slightly longer than necessary. The clicking may only be coming from some of your wheels.
If your spacer is too short, shear load is placed on the bearing raceways, preventing free spin.