Review & Install of Firestone R4 Tech Suspension System

by admin on December 20, 2012

We decided to install the R4 Tech Suspension on the popular Dodge Ram 2500 platform. This truck is a great choice for towing with the assistance of the Cummings motor, and also the rear leaf sprung suspension. The truck can handle heavy loads and does not lack on power to pull. The leaf sprung rear suspension makes this truck a perfect candidate for the R4 Tech kit. This truck had a four leaf with a factory overload spring on it. The truck we picked for this install also had the optional Firestone double convoluted air bags installed on it for extra load support. While the truck had no problem hauling the loads that it was asked to preform, it left very little to be desired of the ride quality. The owner of the truck opted to install the R4 Tech Suspension system. For those of you who don’t know what this system is I will break it down for you. The kit replaces the factory leaf spring with a one and a half leaf spring for a softer spring rate, in combination with an air bag to pick up the weight rating. The kit also replaces the factory shocks with air assisted shocks. Both the air bags and the shocks automatically adjust to compensate for the load changes and road conditions that are different at any given point of the haul. While installing this kit, one of the things we noticed was the quality of the kit. This is a very well put together and thought out kit. It is a complete bolt on kit with no welding or cutting required to install this kit.

Steps to installing kit:

1. Strip all the factory parts in the rear.
This requires supporting the truck from the frame and allowing the axle to hang (supported by axle jacks) to unload the springs while removing them. The shackle is also removed and replaced with this kit.

The shocks will also be removed at this point and for this truck the aftermarket Firestone air bags had to come off as well.

2. Next we start putting parts back on the truck.
This starts with installing the front bracket to the frame. The inner bracket sandwiches the frame then drops down and attach an outer bracket using the factory sprig eye hole. The sandwich design caused us to have to loosen the gas tank straps to gain space on the driver’s side to slide the bracket in between the frame and tank. The lower hole in the front bracket is to accommodate the lower link and J spring. This link spring combination eliminates axle wrap.

3. Now that the front bracket is installed, the leaf springs can be installed.These install right back into the factory position with the new shackles provided.

After the leaves are installed you can start working on brackets that attach the spring to the axle.The axle bracket has a built in height block to ensure proper ride height. They wrap around the axle using the front lower hole to attach the link J spring combo spring and has a pad on top to receive the centering pins from the leaf.

The kit provides new U-bolts but you will have to reuse the factory U-bolt plates.

Installation of the air bags is next up on the plate This step is very similar to installing a regular set of air bags on this truck. It requires removal of the factory bump stops on the frame and a bracket on the axle for the air bag to mount to.

The bag is a heavier duty version to the double convoluted bag in Firestones regular kits.

Time to put on the heart and life source of the system
 The height sensing valves and arms are attached to the upper bracket of the air bags and to the lower bracket of the spring bracket.

As the suspension cycles, the arm attached to the axle moves the height sensor up or down. This adjusts the air pressure in the bags and shocks. If a heavy load is placed on the truck the arm will be forced up signaling the demand of more air in the bags to level the truck out. When the load is lifted the sensor arms will be pulled down activating the dump valves to equal out the air pressure in the bags until level is reached.

The compressor is easily fastened to the side of the frame using the U-bolt Style Clamp around the frame brackets. These brackets make installing the compressor a no brainer. Only wiring and plumbing left.

The wiring is fairly easy as well. Three wires get you up and running. You have a ground wire attached to the chassis, a hot wire ran straight to the battery, and an ignition wire ran to a source controlled by the key.

The kit comes with a tank for on demand air to access air instantly. This allows things like the knee function to work more rapidly. The knee function is a switch that dumps the air allowing the vehicle to drop up to 4 inches to drive under a hitch ball and then flip the switch airing the bags back up to regular ride height.


  • Better ride quality without sacrificing the towing capacity.
  • Easy bolt on installation.
  • Controls axle hop and windup.
  • Offers Kneel function for easy trailer hook up.
  • Keeps load level automatically.
  • Reduces wear and tear on cargo.

Overall we found that installing this kit was a major improvement to the stock suspension. It was fairly easy to install and was custom fit for the application. For what you pay for this kit you really are installing a state of the art suspension system that is able to handle the demands of towing a variety of different trailers and the ever changing road conditions, while keeping the truck level and safe.

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