This Trap Door Ceramic Bearing Upgrade is a high-performance replacement for Harley-Davidson Part #8970A, engineered to handle the unique loads at the trap door/countershaft interface in Big Twin and M8 transmissions. The precision ceramic rolling elements reduce friction, lower operating temperatures, and improve durability compared with standard steel bearings. Designed to maintain proper shaft alignment and support smoother gear transitions under load, it’s ideal for both street riders and performance builds seeking enhanced drivetrain reliability and longevity.
- Direct OEM replacement for 8970A
- Includes one (1) Trap Door bearing
- Installation should be performed by a certified technician, referencing the H-D Factory Service Manual
- Quicker elapsed times and higher MPHs
- Ceramic bearings offer 40% less friction than steel
- Less friction = more horsepower
- 60% less rotating weight
- Low tension, maintenance-free dust seals
- Mobil® Polyrex® lightweight aerospace grease
- Bearing life 3 to 5 times longer than steel
- Lower vibration levels
- Cooler running
- No extra maintenance required
- 2-year warranty
- 100% hand assembled in the USA to exacting specifications
- Why Choose Worldwide Bearings? - Read More
- Worldwide Bearings Ceramic Ball Torture Testing (Video)
Worldwide Hybrid Ceramic Bearings
Speed starts with efficiency. Worldwide Hybrid Ceramic Bearings reduce friction and rotating mass where it matters most—delivering smoother operation, cooler running temperatures, and longer service life than traditional steel bearings. Built with SAE 52100 high-carbon chromium steel races and Grade 5 Silicon Nitride ceramic balls, they’re designed for serious street riders and proven performance builds alike. Finished with low-friction removable seals and backed by a 2-year warranty, these bearings are engineered to win.
