BB MRA 1728 LLB-blk | 17 x 28 x 7mm Bearing

R 8 VV A5 CN - ABEC-5, Radial Bearing (CN Clearance) - 1/2" x 1-1/8"" x 5/16" This ABEC-5 bearing features deep-groove design 52100 High-Carbon Chromium alloy races, with grade 10 Chromium Steel balls and 90% fill Mobil XHP 222 high pressure water proof synthetic grease.VV seals are our lightest contact design, allowing for the fastest spinning bearing we make, though not as protective against the elements as our LLB or LLU type seals. Tighter CN (C0) clearance for looser-fit bearing bores to eliminate bearing play. This size bearing is generally used as a hub bearing for BMX hubs, and some wheelchair hubs. The Enduro line of bearings are available in high-carbon chromium steel, 440C stainless steel, ceramic-hybrid and XD15 with ceramic or stainless balls. Our bearings are always engineered with deepest groove races possible to accommodate the largest balls and feature dual-lip seals that ride in a micro-groove creating a full labyrinth to provide superior protection against the elements.