Washers

I recently let an employee at my favorite local skate shop look over my skates and mess around with them a little. After replacing my bearings, he suggested that I put a tiny washer inbetween each wheel and the axle nut. If you look at any decent pair of skates, there is a little knob where each inside bearing butts up against the truck (see picture).

The little knob makes sure that less of the bearing touches the truck, letting it spin easier. Theoretically the tiny washer on the other side would do the same thing - a lot of skateboards are put together this way, but I haven’t seen too many rollergirls trying it.

Spacers

Spacers go inside each wheel between the two bearings. With spacers in between your bearings, you can tighten the axle nut all the way down on your wheels thanks to the bearings being separated evenly. They also are supposed to prevent bearing from bending or getting dented.

Both washers and spacers should cost you pennies at most. I’ve never used spacers personally on roller skates, and their performance could be based on what type of wheels are used since the size and shape of the hub could differ.