Carli Suspension isn’t just something you stab under your truck’s framerails to fit bigger tires and look cool rolling into the mall. Carli actually engineers its suspension systems, with specially designed applications for Dodge, Ram, and Ford trucks that ride killer, increase wheel travel, and retain on-road drivability and hauling capability without sacrificing off-road performance.
When it came time for the owner of this 2018 Ram 3500 Cummins with the Aisin six-speed transmission to improve the suspension, Carli offered a topnotch lift system to meet its needs. The plan was to build a crawler-hauler-daily-driver-working truck that can go reasonably fast in the desert, crawl rocks, and serve as a recovery and trailer-hauling rig. It’s a tall order, a pickup that can do it all.
Carli offers four 3-inch suspension systems: Leveling, Commuter, Backcountry, and Pintop. For this truck the Backcountry system was used since it improves not only off-road performance but also highway ride. New coil springs and full-replacement Deaver rear leaf packs, along with application-tuned Fox shocks with remote reservoirs, make for a complete package.
To retain good front suspension geometry with the added lift, Carli provides new brackets for the frame to drop the rear attachment point of the radius arms. The plan was to go from the stock 34-inch-tall tires to 37-inch ones. As such, we also used a set of Carli radius arms that are much beefier than stock, use a spherical joint at the frame end, and are angled inward on each side to allow for greater tire clearance at full steering lock.
The Cummins-powered trucks come with a fat torsion bar from the factory that severely limits front axle articulation. It can be retained with the Carli lifts, but we opted to use Carli’s torsion sway bar because it’s tuned to allow the axle to move more freely from the chassis, improving ride quality and trail flex. The lift kit also includes an adjustable front track bar, plus bumpstops and limit straps to protect the Fox 2.0 reservoir shocks under full bottoming and droop conditions. In addition, we added a Carli high-mount steering stabilizer to supplement the stock unit. The radius arms and track bar come preassembled with spherical joints, and Carli provides detailed instructions for the kit build.
The lift was installed at Lamb Fab in Gilbert, Arizona. With two guys working with the truck on a lift, the install was completed in one day. In general, only common mechanic tools were needed, with the exception of a right-angle drill for making some of the holes in the frame. Two limit strap brackets do require welding at the frame. We estimate the lift could be installed in a home driveway over a weekend with two people, given the amount of work needed and the weight of some of the parts.
With the rise in height and fender clearance, it was time to mount some new rubber to the Ram. The truck now turns 37X13.50R17LT Toyo Open Country R/T tires. These are an aggressive all-terrain-type tire designed to provide solid off-road traction combined with comfortable highway ride and handling. The 37-inch tire is a D-rated tread with a load rating of 3,195 pounds at 50 psi.
The new suspension felt firm at first, but after some trailering and a good trail run the springs set in and softened. After a month they keep getting better. With the lift and larger tires, the approach angle was improved by about 8 degrees and departure angle by about 4 degrees. Axle ground clearance went up 1 1/2 inches due to the increase in tire height. The truck rides well both on the highway and off-road. The suspension feels like it wants to roll fast through whoops, and soaks them up cleanly. The truck still tows well while also flexing better in the dirt. The Toyo R/T tires turned out to be a great fit for this project. They are very quiet on the highway, feel stable, and still provide solid traction under most trail conditions we should encounter. Overall, the choice of lift combined with upgraded tires greatly improved the performance of this diesel Ram.
Carli offers several different kits for this application to address the needs of most drivers. In this case, the company’s 3-inch Backcountry system satisfied our use goals and made way for fitment of 37-inch tires.
With the truck up on a lift, disassembly of the front end began with removal of the front sway bar components, shocks, coil springs, and bumpstops. It pays to be thoughtful about where you place the lift pads or jackstands because you need access along the frame to install the new radius arm mounts.
Each factory radius arm was removed from the frame and the axle mount points. For the larger suspension pieces, it helps to have a second person to move the parts in and out.
With the front axle drooped, it was a good time to pull off the factory rubber bumpstops. It’s necessary to drill a hole in each frame mount to allow installation of the Carli drop mount. Here’s where that right-angle drill we mentioned can come in handy.
The provided bumpstop drop brackets were bolted in place and the factory rubber bumps pressed into them.
Here you can see one of the radius arm drop brackets being put into place. These fit over the factory brackets and are secured there and to the transmission crossmember with hardware. They provide a confident, tight fit, so do make an effort to push them into position.
Two new holes need to be drilled in each framerail for additional bolts that secure the drop brackets. Carli provides a 3/4-inch hole saw for this purpose. Clearance is tight in this area, so Tanner Lamb of Lamb Fab in Gilbert, Arizona, used an air-drive right-angle ratchet with a socket on the hole saw to drill the frame holes. There were also burrs left in the factory frame holes that needed to be cleaned up with a carbide burr tool.
With the drop brackets torqued in place, the guys lifted the Carli radius arms in place. The rear end of each arm uses a spherical Johnny Joint that sits in the drop bracket. The front of each arm bolts to the factory axle mount locations.
The Carli linear-rate coil springs were then installed. The spring rate is slightly less than that of the stock springs. A nice part of the kit is the inclusion of the remote-reservoir mount for each shock. It simply sits above the coil spring isolator and is held in place with spring pressure.
Shocks used are Fox 2.0 remote reservoir dampers that are specifically tuned for the application. They are rebuildable and fully serviceable.
Each front shock reservoir mounted cleanly to the reservoir bracket using a pair of screw clamps.
The Carli heavy-duty track bar was installed to replace the factory part. A high-quality FK rod end is used at the axle to allow for side-to-side adjustment, based on lift height.
With the front axle fully drooped to the full extension of the shock travel, the position of the limit strap mounts could be determined. An upper mount was welded onto the frame on both sides of the truck. At this time it was confirmed that there was sufficient slack in the brake lines and ABS wiring at the knuckles.
Front limits straps connect on top to the welded frame mounts and to the radius arms below. If a welder is not readily available during suspension installation, the truck could be driven to a location where the limit strap mounts could be welded.
It is possible to retain the factory sway bar with this kit. However, it’s quite large and greatly limits front axle articulation. A Carli torsion sway bar was used instead. New mounts with polyurethane bushings support the torsion bar and steel arms.
Adjustable links with spherical rod ends connect the Carli sway bar arms to the factory axle tabs.
The factory steering stabilizer was retained and a Carli high-mount steering stabilizer added. It attaches to a new mount bolted to the frame and a billet clamp that is secured to the factory draglink. The stabilizer comes precharged with 200 psi nitrogen. Carli advises that you adjust the charge as needed down to a minimum of 70 psi.
Carli offers a progressive add-a-pack option for the rear suspension. However, the company recommended its Deaver progressive full spring packs for just a slight lift and better trail articulation. The factory rear shocks and leaf packs were removed from the rear axle.
The stock shackles are reused, so they were transferred over to the new Deaver spring packs.
The Deaver packs were secured with the provided U-bolts that were trimmed to length after installation. On the driver side, the parking brake cable was disconnected, rerouted on the frame, and then reconnected. This provides the extra length needed for the cable when the new suspension is flexed out.
Fox 2.0 remote-reservoir shocks were also bolted in place in the rear. Clamps were provided to attach the reservoirs directly to the shock bodies.
The Toyo Open Country R/T tires were mounted on 17x8.5 Method Standard wheels with 25mm offset. With the steering at full lock, the outer edge of the tire rubbed just slightly on the back edge of the fender opening. Minor body trimming quickly fixed the issue.
R/T on this Open Country tire stands for rugged terrain. The tires come with raised sidewall patterns, with a choice of a different pattern on each side of the tire. Stone and mud ejector bars sit at the root of the open shoulder tread blocks to help release and flush material out and away from the tread.
On the street, we ran 50 psi in the tires. With pressure dropped conservatively to 30 psi on the heavy diesel truck, we experienced good sidewall flex for traction and a smooth trail ride. Toyo offers a 45,000-mile treadwear warranty on the Open Country R/T tires.