ACB4051K (MR009) Headset Bearing 40 x 51 x 6.5 – 36/36

MR009 Bearing – Commonly used as ACB4051K on Trek Emonda, Madone, Domain lower headset bearing. Is used on other headsets too.

• Dimensions – 40 x 51 x 6.5
  
• Chamfers – 36/36
  
• Steerer size – 1.5

This bearing is also referred to as: ACB4051K, W540243, 417578, ACB6808, 072E-RS, ACB3636150 and ME009 

There are multiple options, what do I choose?

The Elvedes premium headset bearings offer ABEC 3 precision, ensuring smoother performance and increased durability compared to the standard option listed. The bearings are made from higher-grade materials that make them ideal for riders seeking long-term reliability, while maintaining the same size specifications.