Big Tire Suspension Upgrades for Dodge Diesel 4x4

Sep. 06, 2011 By Jaime Hernandez

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Dodge Mega Cab Diesel 4x4 with Thuren Fabrication control arms, 37-inch BFG All-Terrain tires wrapped around 17-inch Mopar eight-lug wheels.

In our last article, we successfully installed 37-inch BFG All-Terrain tires with minimal lift using factory Mopar 17-inch eight-lug wheels. The setup worked great, but at full lock we did rub on the control arms. There was also very little space between the tire and fender at the back.

We sought out for a way to rectify the geometry of our suspension in order to be able and fully cycle our front suspension, and so we can make tight turns without any rubbing. Since we were already running KORE Performance suspension up front, the natural progression was to seek their help. We unfortunately found out that KORE ceased production of their control arms that corrected the geometry for larger tires. So we set out to find another control arm company.

Too close for comfort, we sought out help from Thuren Fabrication to correct our suspension geometry to safely run 37s on our Dodge Ram 2500. Rubbing on the control arms, and less than two inches of fender clearance can make things interesting.

After much research and talking to other Dodge diesel owners, Thuren Fabrication kept surfacing as a great suspension company for Dodge Ram trucks. We probed a little deeper into Thuren Fabrication and quickly realized that owner Don Thuren not only makes the stuff, but he also personally tests it on his Dodge Ram diesel. Thuren is an off-road enthusiast that enjoys pushing his diesel truck to the limits out in the desert and trails.

Don Thuren’s Diesel Dodge Video:

We talked to Don Thuren about our third-generation Dodge Ram 2500 Mega Cab diesel 4x4 and our tire-rubbing dilemma. We also mentioned to him that it was important that any modifications we did needed to keep our heady-duty truck able to perform off-road while retaining its ability to tow/haul heavy loads. Thuren confirmed that his new control arms with added bends would be our best bet to move our axle forward and eliminate tire rubbing, all while keeping our tow/haul capacity.

With an added 1/2-inch longer length, Thuren Fabrication control arms allows the use of 37-inch tires (using wheels with factory offset) on third and fourth generation Dodge Ram 2500/3500 4x4 diesel trucks.

According to Don Thuren, their control arms are a great addition to any 2003-2011 Dodge Ram. The factory control arms are constructed from very thin wall material, and the bushings have too much deflection. The factory rubber bushings are prone to failure with upgraded suspension travel.

Some other features are:

• Lower arms are built from high-strength DOM tube, and the upper arms are solid alloy.
• 1/4-inch wall lower tubes for impact strength, and new version arms have bends in the lower arms for more tire clearance.
• Fully greasable, adjustable, and rebuildable joints.
• Powdercoated arms are sand blasted, primer coated, then gloss coated.
• Arms are built in precision fixtures to ensure perfect alignment.

We ordered up a set and waited a few weeks for them to be fabricated and shipped. Thuren is in high demand, and there’s a reason for it--they make good stuff.

INSTALLATION
The installation of Thuren Fabrication control arms can be done with the truck sitting on the ground. Thuren recommends doing one side at a time. This ensures the front axle doesn’t shift.

We sought the help of Off Road Warehouse in Escondido, Calif., for our latest suspension upgrade.

Doug Ebba at ORW has been working on our Dodge Ram Mega Cab and was ready to tackle our latest modification. Since our truck spent time in Texas and Louisiana early on, it had accumulated some rust around the pivot bolts. It needed a good amount of deep penetrating oil to loosen up those rusty suckers.

After wrestling with our rusty pilot bolts for a while, Doug was able to loosen them and get the factory control arms out. A top view of the upper control arms shows the inboard curved design of the Thuren arm, which allows greater turning radius for large tires.

On some Cummins diesel trucks, the pivot bolts closest to the exhaust side may need to be cut off in order to remove the upper control arm. There isn’t enough clearance to remove the bolt without taking the exhaust pipe off. Replacement pivot bolts are provided by Thuren for such cases.

After getting the top and bottom Thuren control arms in place for both sides of our front axle, Doug moved on to tighten the pivot bolts and torque them to spec.

To finish it off, Doug checked the front-end alignment and got everything dialed in. There was very minimal adjustment needed, which is a good sign for the geometry of our suspension.

While we were at it, we also upgraded our stock steering stabilizer with a new Bilstein 5100 Series. This new line of performance steering stabilizers offers a great alternative to stock twin-tube models.

The Bilstein 5100 Series steering stabilizer is a must for any truck or SUV running large off-road tires. The nitrogen-charged steering stabilizer keeps positive pressure on the steering components, which make driving and handling much more predictable on and off-road. The installation is simple and will fit into the stock location without having to use an aftermarket clamp.

Dodge 2500 Diesel 4x4 equipped with Bilstein 5100 Series monotube steering stabilizer (Part# BS-BE5-H079-H0).

Here are some features of the Bilstein 5100 Series steering stabilizer:

• Gas pressure monotube design eliminates cavitation and foaming
• Precise steering damping
• Reduces wear and tear of steering components
• Durable corrosion resistant Bilstein Triple C process zinc finish
• Patented digressive valving
• Features highest quality components
• Offers optimum driver comfort & confidence
• O.E. Replacement 36mm & 46mm models
• Fits 2003-2007 Dodge Ram, 4x4

FINAL THOUGHTS
We are really pleased with the Thuren Fabrication control arms and their high level of craftsmanship. The truck rides and handles a lot better, and no more tire rubbing.

We have also noticed that the front axle has some new characteristics as well; it moves much more freely off-road with the Thuren Fabrication control arms. It also makes running a 37-inch tire with a Low COG suspension setup much more feasible since it maximizes turning radius and wheel travel performance.

The added control from the Bilstein monotube steering stabilizer is also a welcomed upgrade that has surpassed the twin-tube stocker. It works well with large 37-inch tires and makes it all come together nicely.

The truck works well loaded and unloaded. We tested it on a recent trip hauling/towing our Lance overhead camper and car trailer with a 5,000 lb. trail toy. It handled great. The front end never felt floaty and we had full control while driving up curvy mountain roads.

If you’re serious about running 37s with maximum suspension performance and safety, Thuren Fabrication control arms along with a Bilstein monotube steering stabilizer is the way to go.

SOURCES:
Thuren Fabrication
http://thurenfabrication.com/
805-886-9250

Bilstein Shock Absorbers
http://www.bilsteinus.com/
858-386-5900

Off Road Warehouse
http://www.offroadwarehouse.com/
800-341-7757