Part of the allure of SRAM's Red component group is that it's designed and made with a pull-out-all-the-stops attitude, and that insistence on lighter, faster, better goes all the way to the bottom bracket. SRAM Red uses the GXP/Blackbox Ceramic Bottom Bracket. It's structurally identical to the Team GXP bottom bracket used in the Force group, except the Blackbox Ceramic GXP uses silicon nitride ceramic balls in the sealed cartridge bearings instead of the less expensive and significantly less round steel balls.
This greater roundness and superior hardness substantially reduces the mechanical drag of the bottom bracket as the crankarm spindle rotates through it. After aerodynamic drag, mechanical drag is the leading culprit in consuming the power you put into the pedals. Can you go faster with ceramics? The answer is a simple and emphatic yes.
SRAM's bottom brackets, while interchangeable between all SRAM cranksets, are brand specific -- meaning, they can only be installed with SRAM cranks. The key element that makes them different from a Shimano or FSA bottom bracket is that the left side bearing has a smaller diameter to mate with the stepped spindle of the SRAM crank. This design allows the inner race of the left side bearing to be captured between the crankarm and the spindle, effectively locating the crank. The right side bearing "floats" on the spindle handling only radial loads as you pedal. The SRAM design optimizes bearing load, minimizes drag, and gives you more durability.
The GXP/Blackbox Ceramic Bottom Bracket has alloy cups, anodized in Red, and is compatible with all SRAM road cranksets -- Red, Force, and Rival. It's available in your choice of English(68mm) or Italian(70mm) threading.
- Made with silicon nitride ceramic balls in sealed cartridge bearings
- Ceramic bearings are lighter and more efficient than standard bearings
- Ceramic bearings use a more rounded cut to reduce mechanical drag
- Compatible with all SRAM road cranksets