Medway B10/50MM-3GS-2Z Kart Axle Bearing – 50 × 90 mm, 2Z Shields, C3 Clearance, 3 Grub Screws – 50mm Axle, 90mm Carrier

The Medway B10/50MM-3GS-2Z is a precision 50 × 90 mm sealed ball bearing built for kart rear axles. Three integral grub screws clamp the bearing to the axle while the double metal shields keep track dust and debris out of the race. It uses a 50mm bore, 90mm outer diameter, 2Z double metal shielding, C3 internal clearance, and a polymer cage. The inner race is extended on one side and carries three drilled-and-tapped grub screws — that's the collar that clamps directly to the axle. C3 clearance gives extra room for thermal expansion under sustained load so the bearing runs cooler than a standard-clearance equivalent, and the 2Z shields seal out grit without the drag of a contact seal. This bearing fits any kart chassis running a 50mm rear axle with a 90mm bearing carrier or cassette. Not every 50mm-axle kart uses a 90mm outer diameter — some setups use 80mm carriers (the B8/50MM-3GS-2Z variant) — so measure your existing carrier or take the old bearing to a digital caliper before ordering. New, manufacturer-fresh stock from Medway Power Transmission Ltd, a UK manufacturer (the bearing brand formerly trading as Dunlop BTL).