Enduro bearing ACB6808 SS 290413 40x51x6.5mm 36x36 deg

ACB 6808 SS, 290413 - 1-1/2" 440C stainless steel Angular Contact Headset bearing (40mm x 51mm x 6.5mm: 36 x 36deg)

Angular-contact headset bearing featuring 440C stainless steel balls and races for superior corrosion protection. Please note that this bearing has slightly different dimensions from the other ACB 6808 bearings we sell, it has a slightly smaller OD and has 36 degree chamfers internally and externally. It was originally spec'd by Trek on Madone and Domane bikes.

This size bearing is also known in the bike Industry by these part numbers:
W540243
417578
ACB3636150

Not all stainless steel is created equal.
Enduro only uses 440C stainless steel balls and races to provide long life and superior corrosion resistance in applications and environments that may be less than ideal. 440C has the highest strength, hardness, and wear resistance of all the standard 440-series stainless alloys with high carbon content. As expected, it is also the most expensive of the 440 series alloys and requires multiple rounds of heat treatment and cryogenic treatment to achieve its superior mechanical properties. Though stainless steel has 20% less load capacity and is slightly softer than our standard 52100 chromium steel used in most of our bearings, stainless steel is an excellent alternative for use in wet conditions, if you wash your bike often, or where sweat can be a problem. Enduro Bearings also uses LLB type seals and CRC Marine grease in these bearings to additionally water proof against the elements. Enduro 440C stainless headset bearings are the same bearings found in many popular headset brands, including those that carry a 110 year warranty. All Enduro stainless headset bearings carry a limited lifetime warranty.

The Enduro line of headset bearings consists of two basic performance levels that are a substantial step up from standard bike industry specifications. Enduro "entry-level" headset bearings feature premium materials like Black-Oxide treated races and carry a two year warranty, while our premium 440C stainless headset bearings carry a full lifetime warranty. 

All Enduro bearings are always engineered with the largest balls possible and feature dual lip labyrinth seals for maximum protection against sweat and the elements and to contain the 90% high pressure water proof grease, keeping everything running smoothly for the duration. The Angular Contact (A/C) design of Enduro headset bearings allow all balls in the bearing to engage the load, spreading the force over a larger surface area minimizing any possibility of premature wear and greatly extending bearing life.

Static load - 917lbf / 4.08kN
Weight - 23.36g