Amazon.com: 8 Pack 32 x 58mm 82A Roller Skate Wheels with Bearing for Indoor or Outdoor, Rolitwils Quad Roller Skate Wheels with Multi-Function Portable Skateboard Accessories T Tool for Double Row Skating :
How to take care of your skates' wheels - InMove Skates Learning Center
All About Bearings: Bearings 101 - RollerSkateNation.com