Progressive Suspension 04140387 Fork springsRef : PRSU00033A / 04140387

Progressive Suspension – Monotube Cartridge Kit (manufacturer part no: 31-2503)

This monotube cartridge kit transforms a dual-tube fork into a high-performance cartridge fork without modifying the fork body. Designed for Vintage/Classic enthusiasts seeking more precise handling, it combines gas monotube cartridges with custom fork springs for a safer and more predictable front-end behaviour.

• Fork tube diameter: 41.00 mm
• Style: Monotube
• Height adjustment: Standard
• Unit supplied: Complete kit
• Manufactured in: United States

Expected benefits include improved dive resistance under braking, increased front stability when entering corners, enhanced cornering grip, and more effective bottoming management. The kit includes calibrated springs to match the cartridges and provide a more consistent damping response, ideal for use on winding roads and for heavier Softail-type bikes.

Lowering option available (front lowering up to 2") — note: lowering kits are not compatible with Low models. Common compatibilities: Harley-Davidson FXSTC, FXSTB, FXSTI (years and engines listed for reference).