What is the difference between a ball bearing and a roller bearing ?

A roller bearing is a cylindrical component designed to facilitate low-friction motion for a bushing or bearing block.

Alternatively, a ball bearing is a spherical element that serves the same purpose.

The primary distinction lies in the contact area between the bearing and the rail. In the case of ball bearings—assuming perfect sphericity and no deformation—the contact area is a single point. Even when deformation is taken into account, the surface area where the ball interfaces with the rail remains relatively small. This limitation gives rise to an inherent strength threshold for ball bearings.

Conversely, roller bearings offer a linear contact zone, significantly enhancing the system's rigidity, stability, and maximum load-bearing capacity.

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