BDL Polished Billet Aluminum Inner Primary Spacers for Harley-Davidson Wide Tire Offset Applications

BDL Polished Billet Aluminum Inner Primary Spacers for Harley-Davidson Wide Tire Offset Applications

When building a custom chopper or fat tire bagger, pushing your rear tire width beyond stock limits often requires offsetting the transmission to maintain proper chain or belt clearance. These BDL Inner Primary Spacers are the professional-grade solution for filling the resulting gap between the engine and the inner primary. By providing a solid, rigid bridge, these spacers ensure a perfectly aligned drivetrain assembly that can handle the torque of high-performance V-Twin engines.

Precision-engineered by Belt Drives Ltd., each spacer is CNC-machined from high-quality billet aluminum and finished with a high-luster polish. Because the primary acts as a critical structural member between the engine and transmission, these spacers are machined to exacting tolerances to prevent case flex, binding, or oil leaks in closed primary systems. They offer a stable mounting surface that maintains the structural integrity of your driveline while accommodating significant wide-tire offsets.

Technical Specifications

• Material: CNC-Machined 6061-T6 Billet Aluminum
• Finish: High-Luster Polished
• Inner Diameter: Standard Big Twin Primary Profile
• Available Thicknesses: 1/4 Inch, 1/2 Inch, 3/4 Inch, 1 Inch, 1-1/4 Inch, 1-1/2 Inch
• Manufacturing: Made in the USA

Key Features

• High-grade billet aluminum construction ensures maximum strength and a precision fit.
• Optimized for custom frames and wide tire kits requiring significant transmission offsets.
• Parallel surface precision eliminates stress on engine and transmission cases by ensuring square alignment.
• Show-quality polished finish complements both open belt drives and stock-style primary setups.
• Maintains the primary as a rigid structural member of the drivetrain.
• Reduces the risk of drivetrain vibration and premature component wear.

Installation and Fitment Notes

• CRITICAL REQUIREMENT: Must be used in conjunction with a corresponding offset motor sprocket/pulley insert and extended mounting hardware (sold separately).
• Application: Designed for use with BDL open belt drives or stock-style inner primary covers in offset configurations.
• Transmission Offset: Moving the transmission to the left requires a matching offset transmission plate (not included).
• Safety: Verify all mounting bolts are of the correct length to ensure full thread engagement into the engine case.