This size bearing is also known in the bike Industry by part number HD446K
BKS-0241 - T47-Internal
90% fill Kluber NBU52 grease only runs better and smoother with time and is highly resistant to being washed out
Inner Race Width - 19
This process also provides a secondary advantage of heat treatment making them tougher
CO 6808 VV - Enduro Zero, Black-Oxide, Ceramic Hybrid, ABEC-5, Radial Bearing (C3 Clearance) - 40mm x 52mm x 7mm sale This size bearing is alsoCO 6808 VV Enduro Zero, Black Oxide, Ceramic Hybrid, ABEC 5, radial bearing (C3 clearance) 40mm x 52mm x 7mm Enduro Zero, Ceramic Hybrid, ABEC 5, radial bearing featuring black oxide treated 52100 High Carbon chromium alloy races paired with Grade 5 Silicon Nitride Ceramic balls with 90% fill, high pressure, water proof grease. Si3N4 ceramic balls reduce bearing wear and increase bearing life by eliminating steel on steel contact within the bearing.