Fox Racing Shocks 981-02-391-1 4.0 Factory Series External Bypass Piggyback Reservoir Shock 4-Tube Custom Valving 14.0 in. Stroke

The Fox Racing Shocks 981-02-391-1 is a 4.0 Factory Series External Bypass Piggyback Reservoir Shock built for serious off-road racing and high-performance trail use. Featuring a 4.0-inch body, 14.0-inch stroke, and a 4-tube external bypass configuration, this shock delivers the position-sensitive damping control and adjustability demanded by racers and hardcore enthusiasts alike.

The bypass design allows the shock to behave differently at various points in the suspension travel, providing a progressive damping curve that eliminates harshness over whoops and rough terrain while maintaining high-speed control. External compression, rebound, and free bleed bypass adjusters let you fine-tune damping behavior without disassembly.

Key Features:

• Body Size: 4.0 inches
• Stroke: 14.0 inches
• Extended Length: 38.54 inches
• Collapsed Length: 24.54 inches
• Bypass Tubes: 4-tube external bypass (2 compression / 2 rebound)
• Shaft: 1-1/8 in. diameter 17-4 H900 hard chrome-plated stainless steel
• Valving: Custom valving configured for specific applications
• Body: Smooth bore, honed seamless steel with zinc plating for long-lasting corrosion resistance
• Components: Black anodized, CNC-machined 6061-T6 billet aluminum
• Seals: High-temp Viton redundant sealing pack (main seal, wiper seal, and scraper seal)
• Oil: JM92 Advanced Suspension Fluid for consistent performance across variable temperatures
• Bearings: Spherical, PTFE-lined, heat-treated alloy steel
• Reservoir: Piggyback style with rotating body cap for easy routing clearance
• Finish: Black anodized aluminum components / Zinc-plated steel body
• Adjuster: Gen 3 clicker adjusters with color-coded compression, rebound, and gold valve seals
• Warranty: Fox limited one-year warranty against defects and premature failure

The rotating body cap design allows the piggyback reservoir and bypass tubes to be repositioned during installation, simplifying fitment in tight or complex suspension configurations. This shock is 100% rebuildable and serviceable, ensuring a long lifespan with proper maintenance. All necessary washers, bushings, and nuts are included. Sold individually as one shock absorber.