The Overbearing: A Modern Fix for a Century Old Problem
Worn-out main drive gear bushings and leaky mainshafts have plagued Harley transmissions for decades—The Overbearing solves both.
This innovative upgrade features a high-strength, hardened drive gear nut paired with a precision-ground bearing. By keeping the mainshaft and main drive gear perfectly concentric, it eliminates bushing wear and drastically reduces—if not outright eliminates—mainshaft leaks.
Now Available in Two Versions:
Overbearing (Original) – Designed for use with all OEM clutch and drive components
Overbearing 2.0 – Updated with a narrower 3/8" bearing for added clearance when running aftermarket clutch baskets in custom builds
• Ensures perfect concentricity between mainshaft and drive gear
• Eliminates bushing wear and mainshaft leaks
• Fits all Big Twin 4-speed transmissions, 1964 and earlier
• Made in the USA
Run your Knucklehead or Panhead transmission with more horsepower and longer intervals between rebuilds. The Overbearing keeps your drivetrain tighter, cleaner, and built for the long haul.
*NOTE*- The Overbearing is intended for all big twin 4 speed transmissions pre-1965. The Overbearing is designed to work in the minimal space allowed in OEM situations. In the event aftermarket clutch baskets or aftermarket transmission sprockets are used, a minimal amount of material may need to be removed from the backside of the clutch basket to allow proper room for the Overbearing. In stock applications, the Overbearing will slightly overlap the taper on the mainshaft, but will maintain approximately .030" clearance between itself and the clutch basket.
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