ReadyLift 43-21450 4-Inch Coil Spring Lift Kit with Falcon 3.3 Coilovers for Ford Super Duty

The ReadyLift 43-21450 is a 4-inch coil spring lift kit engineered specifically for 2017–2022 Ford Super Duty F-250 and F-350 4WD diesel trucks. This complete suspension lift system pairs specially engineered front coil springs with Falcon 3.3 Fast Adjust coilover shocks to deliver a commanding stance without sacrificing ride quality or everyday drivability.

Key Features:

• 4 inches of front lift using precision-engineered replacement coil springs
• Falcon 3.3 Fast Adjust Dampers with two separate adjustment knobs for terrain-specific tuning
• 3-Position Fast Adjust Knob for Soft, Custom, and Firm compression settings
• Soft mode partially bypasses the main piston for a more compliant ride on the street
• 8-Position Micro Adjust Dial for refined damping control
• Reservoir design increases nitrogen-to-oil ratio for consistent damping across temperature ranges
• Hard-anodized large-bore 6061-T6 aluminum shock body for impact resistance, corrosion resistance, and increased oil volume
• VOD (Volume Optimized Damping) with a digressive linear piston for reduced body roll and improved bottom-out resistance
• Red Line high-VI shock oil rated from -50°F to 450°F for all-weather performance
• Bolt-on installation — no structural modifications required
• Accommodates up to 37-inch tall tires on 9-inch wide wheels
• Includes front track bar relocation bracket to maintain proper suspension geometry

Important Notes:

• Designed for diesel-powered trucks only — not recommended for gas engine applications
• For 4WD configurations only — not recommended for 2WD trucks
• Tremor package trucks may not achieve the full 4 inches of lift over stock ride height
• Single Cab configuration fitment and drivability has not been validated by ReadyLIFT

The ReadyLift 43-21450 gives Super Duty owners a premium upgrade path to larger tires and improved ground clearance while maintaining the handling confidence and control expected from a purpose-built suspension system. Professional installation by a certified mechanic is recommended.