December 2020 | By: Vera Catalfo

Ball Joint Bearings 101: Spoiler Alert – Not All Metal Bearings Are The Same

It goes without saying that a bearing’s material will dictate how well it will perform and last. The best bearings are built for endurance and strength, have a low coefficient of friction, stand up to wear and resist deformation, heat and chemicals. If you want to know which bearings are best for your customers, it’s a good idea to take a look inside. However, because you don’t regularly cut ball joints open to see their internals, our latest on-demand webinar will give you a look inside each ball joint technology – so you can see the very real differences.

What Are Ball Joint Bearings?

The bearing of a ball joint is a buffer material used between the ball pin’s sphere and the ball joint’s housing.

What Are The Different Bearing Technologies?

Metal on Metal: These ball joints are actually a non-bearing technology, and they are pretty much obsolete. They have a solid milled steel upper bearing, and the housing is milled out to act as the bearing surface.

– Non-bearing technology
– Must be lubricated
– High friction
– Increased breakaway torque
– Risk of fretting corrosion
– Obsolete design

Polymer: With polymer bearings, a plastic cup acts as a bearing. Extremely reactive to contamination, they are usually non-serviceable and wear rapidly once the lubrication is gone.

– Low cost
– Light weight
– Very low friction
– Deform easily
– Soften under high heat
– Cannot be lubricated with typical grease

Sintered Metal: With sintered metal bearings, the upper and lower bearings are made of sintered powder metal, and a Belleville spring provides consistent pre-load.

– Longer lasting
– Extremely durable
– Handle high impact and loading
– Low friction
– Impervious to heat
– Serviceable

Why Are Sintered Metal Bearings Superior?

Polymer and sintered metal bearings both have their place in the aftermarket, depending on the demands of the application. Polymer bearings were originally introduced by OEMs as a lighter, lower-cost alternative to metal. However, sintered metal bearings last 3 times longer than polymer. They can operate in a high heat environment without deforming, and they stand up to heavy wear and fatigue. Any GC-LB grease can be used to service the part without fear of damaging the bearings, and their porous nature means they are continuously self-lubricating.

Overall, sintered metal bearings are the more durable, longer-lasting choice.

Want to see for yourself? Watch the brief webinar to get a look inside the parts.