The Firestone Coil-Rite Air Helper Spring Kit Rear is a performance upgrade designed for vehicles with coil spring suspensions. This kit features air helper springs that fit inside existing coil springs to provide a variable spring rate, helping to level the vehicle and improve braking and handling under heavy loads or challenging road conditions. Constructed from durable, elastic polyurethane, these springs support 500-1000 lbs per set (not exceeding the vehicle's GVWR) and allow for easy air pressure adjustments, enabling precise load leveling and ride comfort. The Coil-Rite system enhances vehicle stability and comfort by enabling quick modifications to spring performance, similar to inflating a tire, making it ideal for towing or carrying heavy loads.

This kit is compatible with 1998-2017 Toyota 4Runner models, regardless of engine configuration, and is designed for rear installation. It is suitable for use in a wide temperature range from -40°F to 180°F, ensuring reliable performance in various climates. The installation involves fitting the air springs inside the existing coil springs, providing a straightforward upgrade for improved load support and ride quality. The kit is intended for daily driving, towing, and off-road use, offering enhanced stability and control when carrying heavy loads or navigating uneven terrain.