What are bearing spacers?

One of the above bearing spacers is placed between the two bearings that are housed in each inline skate wheel. They are difficult to damage but easy to lose. They are often thrown out with old wheels, forgetting, or not realizing they will be needed when new wheels arrive. Should this happen, fear not! Inline Warehouse sells spacers individually at around $1 each.

Yes. Despite seemingly not having any purpose, they perform a very important role. Assembled in the center of the wheel hub, spacers align with the center ring of the bearings to allow tightening of the frame axles without the frame bending or pinching the wheels. This bending and/or pinching will prevent the wheel (or wheels) from spinning freely and affect performance. Bearing spacers also work to distribute the weight load to lessen stress and prolong the life of the bearings (and even the axles). To put it simply, they make wheels roll better and for longer.

The axle size used on the skate frame (8mm or 6mm) determines which bearing spacer is to be used. Rather than trying to measure, a simple way to determine which is needed is to slide the frame axle through the center hole of a bearing. If the frame axle fills the entire space, it is an 8mm axle requiring 8mm floating bearing spacers. If it does not, it is a 6mm axle requiring 6mm long sleeve spacers that fill up the extra space. Both are imaged below with a Sonic 6mm on the left and a Sonic 8mm spacer on the right.

If buying new wheels with pre-assembled bearings and spacers and your axles do not fit through the bearing or they are loose, the wheels and/or bearings are not defective. They are simply pre-assembled with the incorrect bearing spacer for the axles being used.

NOTE: Bearing spacers and wheel hubs can vary in size due to manufacturing tolerances. Although not able to be seen by the naked eye, such tolerances can cause a wheel to make a clicking noise while skating or prevent it from spinning freely. Replacing the bearing spacer is most often the fix.