2003-2025 Toyota 4Runner Firestone Coil-Rite Rear Air Helper Spring Kit | Part# 4135

4Runner Firestone Coil-Rite Rear Air Helper Spring Kit Features:

• Supports up to 1,000 lbs of load
• Fits inside factory rear coil springs
• No-drill, bolt-on installation
• Installs in about one hour
• Manual inflation valves included
• Adjustable for uneven or shifting loads
• Improves handling and ride control
• Reduces suspension fatigue and sag
• Made from durable polyurethane material
• Operates from -40F to 180F
• Helps reduce tire wear and sway
• Helps prevent bottoming out

Premium Rear Air Bags for Loaded Suspension

When you're loading up the 4Runner for a weekend getaway, hauling extra gear, or towing something heavier than usual, the stock suspension can start to feel overwhelmed. That’s where the Firestone Coil-Rite Rear Air Helper Spring Kit steps in. Designed specifically for 4Runners running a coil spring rear suspension, this system fits neatly inside the factory coils, giving you a smart and reliable way to balance load support with ride comfort. Unlike Firestone’s Ride-Rite kits, which mount between the frame and leaf springs, the Coil-Rite system is made for vehicles with coil springs and focuses on subtle control and adjustability from within. The real magic is in the way these air springs offer a variable spring rate; meaning they firm up under load but stay soft and comfortable when you're unloaded. It's a great setup for folks who use their 4Runner as a daily driver during the week and load it down on the weekends for camping, gear runs, or towing a small trailer.

High-Quality Construction with Straightforward Install

Each air spring is made from durable, elastic polyurethane that’s built to handle extreme temperatures; whether you're tackling mountain trails or just navigating through brutal winter cold or desert heat. The kit includes everything you need for install: air springs, hardware, air lines, and manual inflation valves you can fill just like a tire. No drilling required for most applications, and install time usually clocks in around an hour. Once installed, you'll notice less rear-end sag, more confident handling, and improved braking control–especially when you're carrying extra weight or dealing with uneven cargo. Body roll is reduced, headlights stay aimed where they should, and tire wear evens out thanks to a properly leveled ride. Behind the wheel, that translates to a smoother, more planted feel with far fewer surprises when you hit bumps or uneven pavement.

Fits: 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025 Toyota 4Runner

Note: Custom modifications may be required for lifted applications to ensure air bags are properly supported. If using on a lifted application, do not follow Firestone bump stop/jounce cut instructions. You will need to determine where to cut based on your lift amount.