When you go to buy roller skate bearings, you’ll notice most manufactures offer skate bearings in two sizes (7mm & 8mm). The size refers to the diameter of the skate axle, that fits inside the bearing. 8mm bearings are very common, but some plates manufactures still use 7mm axles. When it doubt, it’s always best to know what size you’ll need.
Here is a real easy trick to help determine your axle/bearing size.
- Skate tool to remove the wheel from the roller skate
- #2 Pencil
Step 1) Remove wheel from the roller skate.
Step 2) Stick a #2 pencil into the center of the bearing (small hole where the axle would go).
-If the pencil fits, the bearing is 8mm.
-If the pencil does NOT fit, then it is a 7mm bearing.