Firestone 4173 Coil-Rite Rear Air Helper Spring Kit for 07-18 Jeep Wrangler JK

Vehicle Fitment

• 2007-2018 Jeep Wrangler (JK 2-door; 3.6 L V6; 2WD/4WD)
• 2007-2018 Jeep Wrangler Unlimited (JK 4-door; 3.6 L V6; 2WD/4WD)

Fitment Notes

• Rear coil spring air assist only; not compatible with Rubicon models
• Does NOT require drilling for installation
• Manual fill only; air compressor sold separately

Features

• High-strength polyurethane air springs integrate inside OEM rear coils
• Adjustable 5-35 psi for load support from 500 lb to 1,000 lb
• Improves handling, braking, and ride comfort under load
• Temperature rated for -40 °F to 180 °F performance
• Includes air lines, inflation valves, and mounting hardware
• No welding or drilling required--OEM bolt-on simplicity
• Backed by limited lifetime warranty
• Quick 1-2 hour install time per side

Specifications

• Part Number: 4173 (Coil-Rite Rear Kit)
• Rear Axle Position; Bellows Material: Polyurethane
• Air Spring Size: 5.5" diameter x 7" length
• Operating Pressure: 5-35 psi; Capacity: 500-1,000 lb per set
• Temperature Range: -40 °F to 180 °F
• Warranty: Limited lifetime (bellows); 2-year on hardware

Included Components

• 2x Polyurethane air helper springs
• 1x Pre-assembled air line and fittings
• 2x Manual inflation valves with caps
• Mounting brackets, bolts, washers
• Instruction manual with torque & fill-pressure guide

Product Description

The Firestone 4173 Coil-Rite Rear Air Spring Kit is designed specifically for 2007-2017 Jeep Wrangler JK models (2-door and Unlimited 4-door) with 3.6 L V6 engines. This reliable air helper spring kit installs inside the factory rear coil springs, offering adjustable support between 5-35 psi to improve ride quality, handling, and braking under heavy loads without sacrificing comfort.

Featuring durable polyurethane bellows rated from -40 °F to 180 °F and supporting up to 1,000 lb of cargo weight correction, the 4173 kit is a simple bolt-on solution--no drilling or welding required. Installation takes roughly 1-2 hours, and the system is backed by Firestone's lifetime warranty on bellows and 2-year hardware coverage. Ideal for Wrangler owners needing extra support for towing, off-road gear, or heavy rear-end loads.