Control arms, long arms & caster

What the arms actually do

A solid axle has to be held in three ways: front to back, side to side, and against twisting as the brakes and driveshaft load it. On a coil-sprung axle, the arms and the track bar do all of that and the springs only carry weight. That's why changing spring height without addressing the arms changes where the axle sits.

Front control arms on link trucks (1994-2012/2013)

The factory arms are stamped steel with a bushing at each end. They're fine for a stock truck, but they're fixed length, they can be bent by rocks, and once the truck is lifted they no longer put the axle where it belongs. Common aftermarket choices:

• Fixed-length replacement or extended arms: stronger than stock, sometimes a little longer to push the axle forward again after a lift.
• Adjustable arms (single or double adjustable): you set the length to center the axle in the wheel opening and tune caster.
• Bent or high-clearance arms: shaped to clear bigger tires or rocks.
• Joint choice: rubber bushings are quiet and soak up vibration. Flex-style joints allow more articulation but behave differently on the street. Ask what maintenance they need.

Short arms vs long arms

Every arm pivots at the frame, so the axle end moves in an arc. A short arm gives a tight arc: as the axle moves up and down it also moves noticeably forward and back, and the axle rotates, so caster changes through the travel. A long arm gives a flatter arc, so for the same wheel travel the axle stays closer to where it started. That's the main reason long-arm systems are popular on lifted trucks that see rough terrain.

Lifting also changes the starting angle. With the axle hanging lower, short arms point more steeply up toward the frame, which makes the fore-aft swing and the caster change worse. Long arms start out flatter.

Radius arms (2013-on 3500 / 2014-on 2500)

A radius arm clamps to the axle at two points and pivots at one frame mount, so arm and axle rotate together. The setup is stiff and simple. But a lift rotates the axle and takes caster out with it, and caster keeps changing through the travel because of that single pivot. The usual fixes:

• Drop brackets: restore arm angle and caster and keep the factory arms. You lose some clearance under the bracket.
• Replacement radius arms: stronger arms with built-in caster correction or more adjustment, mounted in the factory location.
• Link or long-arm conversion: separate upper and lower links per side, so caster stays steadier through the travel. It's the most work, but the most control.

The track bar's suspension job

Front and rear, the track bar runs across the truck and keeps the axle centered under it. Because it swings in an arc too, raising or lowering the truck pulls the axle sideways. After a lift, an adjustable track bar is how you put the axle back in the center. For suspension planning, that's the part to remember: the track bar sets side-to-side position, and the axle has to be centered before an alignment means anything.

Track bars also affect how the truck steers. That side of it is covered at the end of this page.

Rear links and traction bars

• 2014-on 2500 link-coil rear: the rear has its own control arms and a rear track bar. Adjustable rear arms set pinion angle and wheelbase, and an adjustable rear track bar re-centers the axle after a height change.
• Leaf rears: the spring locates the axle. Under hard throttle, the axle can rotate and wind the spring into an S-shape (axle wrap). Traction bars resist that rotation.
• Rear link conversions on leaf trucks: replacing the leafs with a multi-link rear is a major build, aimed at off-road travel. Think carefully about how you tow and haul before going that route.

Caster and alignment after a lift

Caster is the tilt of the steering axis, viewed from the side. It's what makes the wheel want to return to center and the truck want to go straight. On a solid front axle the steering axis is fixed to the axle housing, so anything that rotates the housing changes caster:

• Link front: a lift tips the short arms up and rotates the axle. You bring caster back by setting the relative lengths of the upper and lower arms (adjustable arms), or by keeping the arms flatter with a long-arm system. The factory adjustment in the lower arm mounts has limited range.
• Radius arm front: the lift rotates the arm and axle together. Drop brackets, replacement arms with caster built in, or a link conversion bring it back.
• Pinion angle comes along: rotating the front axle for caster also rotates the front pinion, and with it the front driveshaft angle. Good kits are designed to balance the two.

Toe needs resetting after any height change. Camber on a solid axle isn't normally adjustable the way it is on independent suspension. If camber looks wrong, suspect worn or bent parts first. Do the work in this order: center the axle with the track bar, set caster, then set toe.

Steering topics live next door

Track bar angle, bump steer, drag links, steering boxes and death wobble on lifted trucks are covered in depth on our sister site, Dodge Ram Steering's lifted-truck guide. This page sticks to the suspension side so the two sites don't repeat each other.

Arms and links at Dodge Off Road

Last reviewed 2026-10-19. General information for planning. Follow your service information and parts maker's instructions.