Why do roller bearings have a higher load capacity compared to ball bearings?

Roller bearings possess a higher load capacity compared to ball bearings primarily due to their greater contact area. The design of roller bearings allows for a larger surface area of contact between the rolling elements (the rollers) and the raceway. This expanded contact area distributes the load more evenly, which reduces stress on individual rolling elements and prevents deformation under heavy loads.

In comparison, ball bearings, which have a point contact scenario because of their spherical shape, provide less surface area for load distribution. This makes them more susceptible to wear and failure under high load conditions. Therefore, the geometry of roller bearings, which often includes cylindrical or tapered shapes, enhances their ability to support larger loads effectively, providing improved performance in demanding applications.

While factors like size, material strength, and design complexity can also influence the performance of bearings, it is this increased contact area that is a fundamental characteristic allowing roller bearings to bear heavier loads than ball bearings.