Bearing Enduro Bearings ACB 4545 137 Stainless Steel 1-3/8"

Enduro Bearings ACB 4545 137 SS is a stainless steel angular-contact headset bearing. Dimensions: 37 × 46.85 × 7 mm (36 × 45o). It is also known in the bicycle industry by the part number MR137.

Construction and materials

• The bearing balls and races are made of 440C stainless steel for corrosion resistance.
• With its high carbon content, 440C has the greatest strength, hardness and wear resistance of the standard 440-series stainless steel alloys. It is also the most expensive alloy in the series and requires special heat and cryogenic treatment to achieve its mechanical properties.
• 440C is slightly softer than the standard 52100 chromium steel used in most Enduro bearings. Stainless steel is suitable for wet conditions and environments where the bearing may be exposed to sweat or spilled sports drinks.
• LLB-type seals and Almagard 3752 grease provide additional protection against water and the elements.
• Enduro angular-contact headset bearings are made with black-oxide-treated chromium steel races or entirely from 440C stainless steel. They use the largest balls possible and dual-lip seals that run in a micro-groove (labyrinth). The bearing is 90% filled with high-pressure waterproof grease.
• Angular Contact (A/C) bearings are designed to engage all balls evenly. This distributes force over a larger surface area, reducing wear and extending bearing life.
• Enduro 440C stainless steel headset bearings carry a lifetime warranty.

Static load: 680 lbf / 3.02 kN
Weight: 23.3 g