The SRAM GXP BlackBox Ceramic Bottom Bracket Cups, welcome to gutter seal technology. Gutter drastically improves sealing against the elements while reducing seal drag. Sram have designed a fresh new cup forging for a new high end look. A new standard in external bearing performance, now with ultra smooth ceramic bearings that ensure every ounce of your energy translates into on the trail speed. You'll soon be showing you riding partners a fresh set of heels.
GXP is different - and better. Other systems rely on side-loaded bearings to eliminate play, causing bearing wear. GXP captures the left-side bearing between the spindle and left crank arm and allows the drive-side bearing to float axially on the spindle. There's no need to side-load bearings during adjustment. No excess wear and much simpler installation. Just tighten to the proper specifications and you're ready to roll, worry-free. GXP's two bicycle-specific cartridge bearings and eight seals ensure a smooth, long lasting ride. SRAM's new gutter seal system takes a two stage approach in directing contaminates away from the bearings providing longer bearing life. GXP's new gutter seal design also reduces friction, 35% less drag than the current GXP bottom bracket, improving rider feel and performance.