1-1/8" 45°/45° ACB Stainless Headset Bearing

The ACB 4545 1125 SS is a 1-1/8" angular-contact headset bearing designed for maximum life and superior corrosion resistance. Measuring 30.5mm x 41.8mm x 6.5mm with a 45x45 degree angle, it is specifically engineered to withstand wet conditions and exposure to sweat or sports drinks.

Premium 440C Stainless Steel: Unlike standard alloys, this bearing features full 440C stainless steel balls and races. This high-carbon alloy offers the highest strength, hardness, and wear resistance of the 440-series, further enhanced by special heat and cryogenic treatments.

Angular Contact Design: Engineered so all balls are evenly engaged, spreading force over a larger surface area. This design minimizes wear and maximizes the service life of the headset under load.

Advanced Weatherproofing: Equipped with LLB-type dual-lip labyrinth seals riding in a micro-groove to block contaminants. The bearing is 90% filled with Almagard 3752 high-pressure waterproof grease for ultimate protection against the elements.

Industry Compatibility: This bearing is a direct replacement for various industry part numbers, including MR042, 870E, MR121, MR070, MR084, MR116, TH-870E, and MH-P08. It is the same high-standard bearing utilized by many popular headset brands offering lifetime warranties.