Headset Bearing Enduro ACB 4545 405495 SS (40.5×49.5×6.5–45/45) 440C Stainless

Headset Bearing Enduro ACB 4545 405495 SS (40.5×49.5×6.5–45/45) 440C Stainless

The Enduro ACB 4545 405495 SS is an angular contact headset bearing manufactured from 440C stainless steel, designed to deliver maximum durability and smooth steering performance even in harsh conditions. It features 440C stainless steel balls and races for outstanding corrosion resistance and long service life.

This bearing size is also known in the bicycle industry as HSS 6011 ACB495H6.5. Not all stainless steel is created equal – Enduro exclusively uses 440C stainless steel, which offers the highest strength, hardness, and wear resistance of all standard 440-series stainless alloys. Achieving these properties requires specialized heat treatment and cryogenic processing.

Although 440C stainless steel is slightly softer than Enduro’s standard 52100 chromium steel, it is an excellent choice for wet conditions or environments where sweat and spilled sports drinks can cause corrosion. This makes it ideal for demanding riding conditions and long-term reliability.

The bearing is equipped with LLB-type seals and filled with Almagard 3752 waterproof grease for enhanced protection against water and contamination. Dual-lip labyrinth seals riding in a micro-groove and a 90% fill of high-pressure waterproof grease ensure exceptional durability and protection from the elements.

Enduro angular contact bearings are engineered so that all balls are evenly engaged, distributing loads across a larger surface area. This design minimizes wear and maximizes bearing life. 

Technical specifications:

• Type: Angular contact headset bearing
• Dimensions: 40.5 × 49.5 × 6.5 mm
• Contact angle: 45° / 45°
• Material: 440C stainless steel
• Seals: LLB, dual-lip labyrinth
• Grease: Almagard 3752 waterproof grease (90% fill)
• Also known as: HSS 6011 ACB495H6.5
• Application: headset bearings