Ball bearing 61903 (6903) ceramic coated

CeramicSpeed ball bearings are hand built in Denmark. The ceramic balls run in a race coated with metal. They are held in position by a polyamide cage. A "Blue Grease" specially developed by CeramicSpeed is used in each ball bearing. And a non-contact seal protects the balls from moisture and dirt. This makes the ball bearings suitable for all forms of road cycling, but also for gravel and MTB wheels.

During the manufacturing process, the bearings are tested four times by hand for perfection. The result is outstanding: The ceramic balls are 400% smoother, 128% harder and 58% lighter than standard steel balls used in the bicycle industry. But even compared to other ceramic balls, they are 15% harder, 99% stronger and 100% smoother.