Added Sumo Spring model Solo SSR-307-40 to my 2018 RAM 1500 Quad Cab 4×4

I just purchased a left over 2018 RAM 1500 Quad Cab 4×4 (Tradesman). I had previously rented many RAM 1500’s in the past and was very familiar with the 5 link coil spring rear suspension. It provides a very nice unloaded ride, but becomes soft as you reach payload capacity (1,700 pounds in this case). I prefer the rear end of my trucks to be firm; as “squat-free” as possible. Air bags were of course one option, but on a previous truck one failed after approx. 5 years. Granted that particular air spring installed inside the coil, and after years of the coils rubbing up and down on the bags, one sprung a rip in the side despite being very careful to maintain proper minimum air pressure. So I decide to research other options. One option was an air bag system that mounted outside the coils, but that was a 5,000 pound system which was way beyond what I needed in capability, cost and complexity.

I then came across Sumo Springs and knew it was exactly what I was looking for. I opted for the lighter duty 40 series (blue spring) versus the medium duty 47 (black) spring mostly on the basis I was going to install the springs with the provided 1″ spacer so the spring was always engaging the axle. The folks at Super Spring recommended against the 47 series if I wanted the spring constantly engaged even without load – on the premise it would be too firm without load. I took their advice.

I received the springs yesterday and installed them in approx. 90 minutes. The driver’s side was really quick – with not much in the way. The passenger side was a little more difficult as the exhaust system prevent putting a ratchet on some of the bolts. As a result I used a standard wrench but had to make very small turn increments, making the complete tightening of the lock nuts a longer process than expected. However, that is by no means a negative of the product itself. The spring itself feels indestructible and the mounting plates very substantial.

Once installed, I lowered the truck off the jack and noticed how planted the rear end was. Normally the weight of the truck would compress the spring a little (as expected), but having the Sumo Spring working in coordination with the factory coils, kept the rear end more upright. I didn’t measure, but I would say the Sumo spring prevented the rear end from dropping approx. 1/2″ to 3/4″ (again completely unloaded) when taken off the jack. The 1″ spacer allowed the Sumo Spring to make contact with the axle with no load. Pushing down on the bumper, you immediately notice how much firmer the rear end was. Of course you have the option to install the spring without the 1″ spacer where the spring will only engage with a load. I am guessing at least 400-500 pounds would be required to engage the sumo spring on the RAM 1500. Time for a test drive.

As soon as I pulled out of my driveway, I noticed the rear end firmness. Absolutely no drop, bounce and rebound that would normally happen coming out of the driveway. Driving down the road one of the biggest improvements I immediately noted was how much better the truck’s steering was. There was no longer any side to side body motion or roll when taking a turn. It was almost as if I just installed a massive anti-sway bar.

I haven’t loaded down the truck with anything just yet. That will come soon with a trip to the landscape yard for bags of mulch. I fully expect the Sumo Spring will do exactly what it is intended to do under load. This is a great product for anyone who wants a maintenance-free solution to provide supplemental support to a truck’s factory suspension.