There are a number of control arm joints in the aftermarket and they come in a variety of
Control Arm Ends
Lowdown: Your rigs control arms link the axle to the vehicle and they help keep the axle in its proper position. Typically a vehicle with a link-type suspension has a pair of upper and a pair of lower control arms. The control arm ends are what allow the control arms to pivot, thus allowing the suspension to articulate. If they didn’t allow movement, the suspension wouldn’t be able to articulate.
Budget: Rubber bushings
Most factory suspensions utilize rubber bushings in the control arms. Like rubber bumpstops, they’re inexpensive and durable. They’re also great at absorbing road vibration so it isn’t transferred to the cabin. Like rubber bumpstops, oil can impregnate them and make them mushy over time. Rubber bushings have design limits that flexy suspensions and heavier wheel/tire combinations can exceed.
Pros: Inexpensive, durable, they limit road vibrations to the cabin
Cons: Oil can make them mushy over time, they can be overwhelmed by suspension flex and heavier wheels/tires
Better: Polyurethane bushings
Available from a number of aftermarket sources, polyurethane bushings are stiffer than rubber and the result can be better on-road handling. They also typically offer a longer life than rubber bushings and they resist oil. Polyurethane bushings are included in many aftermarket control arms. They need to be greased to seal out water and dirt and they tend to transfer vibrations more than rubber bushings. They’re also prone to squeaking if not properly lubed and they can inhibit suspension flex due to their stiffness.
Pros: Inexpensive, long life
Cons: Need to be greased to eliminate squeaking, stiff, transfer road vibration more than rubber
Best: Joints/spherical rod ends
There is a wide variety of joints and spherical rod ends available for control arms, and they differ widely in construction and strength. One thing they all have in common is that they offer more movement than a standard rubber or polyurethane bushing setup and this will help improve suspension flex. Some joints incorporate urethane or nylon bushings to decrease road vibrations being transferred to the cabin. Also, many of these joints are greasable and rebuildable. Quality spherical rod ends are very strong but they don’t typically use a rubber or urethane bushing, hence they transmit vibrations to the cabin. Most rod ends are not greasable or rebuildable.
Pros: Strong, flexy, many joints are greasable and rebuildable, quality spherical rod ends are very strong
Cons: Both joints and quality spherical rod ends are more expensive than rubber or polyurethane
Cappa: I’m actually a fan of factory rubber control arm ends. In a typical 4x4 application nothing seems to last as long as the factory rubber parts and they are maintenance free. Polyurethane control arm bushings will last nearly forever, but they can be noisy, harsh, and limit movement. They also need to be greased often. Spherical rod ends are best suited in racing environments where they are checked and replaced regularly. On a daily driver you’ll be lucky to get a few thousand miles out of a rod end before it becomes worn and needs to be replaced. If you’re looking for an aftermarket joint with lots of articulation, make sure it’s greasable to keep contaminants out. Currie Johnny Joints or Rubicon Express joints are good options.
Holman: On my links, I prefer factory rubber. The OE engineers have the durability and flexibility nailed and the OE bushings are tuned to keep NVH to a minimum. If you need more flex, Currie’s Johnny Joints are probably the next best thing. Don’t be afraid to run Johnny Joints on the axle end and rubber on the vehicle end. It gives you the best of both worlds: flex and NVH control.
Brubaker: Flex isn’t a big must-have for our work trucks here on the farm. Hence, I just don’t need a fancy, high-tech joint on the ends of my rigs control arms. Nor do I want the hassles of a rod end. I like the no-maintenance, insulating qualities of rubber bushings. I’ve never had a problem with them after years of driving in mud, snow, salt, manure, and rain.