Black Bearing Ceramic bearing 6904-2RS - 20 x 37 x 9 mm

CERAMIC BEARINGS BLACK BEARING: Black Bearing bearings are "hybrid" bearings, more commonly called "ceramic". These bearings meet the constraints of cycling (Road, MTB, CLM, Cyclo Cross ...) and are used for wheels, cranksets, derailleur rollers ... Compared to a standard steel bearing, the advantages of hybrid ceramic bearings Black Bearing are numerous: - Weight saving (density of ceramic < that of steel),- Holding at very high speeds,- Much longer life (several times that of a standard),- Less friction = less losses when pedaling,- Better rigidity,- Better precision,- Better mechanical characteristics (hardness, compression resistance...). The hybrid ceramic bearings Black Bearing Ceramic are composed of the following elements:- Inner and outer rings in treated stainless steel for better mechanical resistance,- Silicon nitride balls,- Steel cage,- Specific low friction seals for water and dust tightness (2RS),- Grease specially adapted to ceramic bearings.