GMC Control Arms

Types of Control Arms: The types of control arms vary widely based on the vehicle suspension type, the arm construction, and the arm's unique features. Below, we have detailed these types to help you decide your best option based on your needs and budget.

Upper Control Arms (UCAs) for Coilover-Style Suspensions

This style of upper control arm comes standard on most current 1/2-ton and midsize trucks and SUVs. The UCA has connecting points at the chassis and at the top of the steering knuckles on the driver and passenger sides.

Function and Benefits

Aftermarket upper control arms are a popular upgrade on models lifted or leveled 2 inches and above using strut spacers, adjustable-height struts/shocks (Bilstein 5100 Adjustable Height, Fox Snap Ring Shocks, etc.), or lifted coilovers (Bilstein 6112 Coilovers, Icon 2.5 Coilovers, Fox Performance Elite Coilovers). These types of lifts can create issues with suspension travel and front-end alignment. Most arms have built caster and camber adjustments to address alignment issues and ball joints or uni-ball joints with a greater range of motion than factory ball joints to improve suspension travel and full suspension droop.

Construction

UCAs are built from several materials. The material will affect the strength and cost of the arms.

1. Tubular Steel:The most common upper control arms are built from tubular steel. They offer a good balance of strength, looks, and function and are generally priced as a mid-range option.
2. Forged Aluminum:Arms built from forged aluminum are a good option for those on a budget while providing excellent strength and durability. Rough Country offers this style for many applications.
3. Billet Aluminum:The billet aluminum arms by Icon Vehicle Dynamics are a premium option. They look great, are very strong, and allow on-vehicle camber and caster adjustments. If your budget allows for a higher price, they are a great choice.
4. Cast Steel:This mid-price option is a significant upgrade. The cast design eliminates the need for welded joints, which can be potential weak points that can be found in other steel options. There are a limited number of applications for this type of arm, but for those that are available, these arms are a solid choice.
5. Boxed Steel:Zone Off-Road offers a variety of boxed control arm options. This alternative to tubular control arms are fully welded and features a more bulky look with hard corners.

Bushing Types

At the chassis connecting/pivot point, upper control arms are equipped with several different types of bushings or rod ends.

Rubber Bushings: Clevite rubber bushings come equipped with BDS, Zone, ReadyLift, and Rough Country upper control arms. These bushings wear very well, do not squeak, and can provide a slightly more comfortable ride than other options due to the softer compound.

Polyurethane Bushings: Brands using polyurethane bushing in their arms include Icon Vehicle Dynamics (tubular arms), Bilstein and Fabtech. These bushings are a more rigid material that tends to wear quicker than rubber, but their 2-piece design makes them easy to replace. Polyurethane bushings do require maintenance. Periodic application of silicone base grease will prevent premature wear and squeaking.

Rod Ends: The Icon Vehicle Dynamics billet aluminum control arms feature PTFE-lined rod ends in place of bushings. These do not require maintenance, are very durable, and will not bind due to the rod ends pivot abilities.

Joint Types

UCAs connect to the upper portion of the knuckle using a ball joint. Aftermarket upper control arms generally use a ball joint or uni-ball that allows for a greater range of motion for better suspension travel. Below are the most common types of joints used in UCAs.

Ball Joint: These consist of a ball enclosed in a socket, made of metal. The ball is mounted on a stud that connects to the steering knuckle. The socket allows for movement in multiple directions, providing articulation for the suspension system. While ball joints offer a good range of motion, they may have limitations in extreme angles and off-road conditions. Ball joints are generally durable but may wear out over time, especially in off-road or heavy-duty usage.

Uni-Ball: This type of joint uses a spherical bearing, a single ball, or a sphere. The bearing is housed in a metal cup or race, allowing for rotation and movement in various directions. Uni-balls provide a greater range of motion compared to traditional ball joints. This makes them popular in off-road applications where increased suspension travel and articulation are crucial.

Hybrid: The Delta Joint by Icon is a heavy-duty high-angle ball joint that combines the durability of a ball joint with the performance of a traditional uniball. It allows for greatly increased articulation with little binding while also protecting from the elements.

Control Arms for Coil Spring-Style Suspensions

These types of control arms can be found on Jeep Wrangler and Cherokee models and earlier Dodge Ram 2500 / 3500 trucks. They consist of an upper arm and a lower control arm for the driver and passenger sides. One end of each arm is mounted to the axle, and the other to brackets on the chassis. The lower and upper arms run parallel to each other and are the primary support for the axle (front &/or rear, depending on application).

When lifting a model with this type of suspension beyond 2 inches, your stock control arms will be too short, causing your axle to be pulled off center. Aftermarket control arms are used to re-center the axle in the wheel well for proper suspension movement.

Fixed vs Adjustable Arms

When upgrading to an aftermarket control arm, you have a few choices to make. A fixed control will likely work great if you are on a budget and/or don't plan to off-road much. This arm is very similar to a factory arm but is longer to compensate for the lift installed on your vehicle. Adjustable control arms differ in that one end of the arm has a threaded end joint. This joint allows for length adjustment, making it compatible with lift kits of multiple sizes. The threaded end joint also eliminates binding for a full range of movement, not restricting articulation. For off-road enthusiasts, an adjustable control arm is the preferred option.

Short Arm vs Long Arm

If you own a Jeep, you may have heard the terms short arm and long arm. While this obviously is in reference to the length of the arms, it really refers to how the arms are mounted. Short arms are using the factory mounts on the axle and chassis. Long arm kits use the factory axle mounts but include new mounting brackets on the chassis that allow for the use of extended-length arms. The long arms will significantly increase suspension articulation. Jack-it offers a great selection of long arm lift kits and control arms. These are designed for serious off-roaders who want to push their vehicle's suspension to the limit.