A ball bearing designed to carry radial loads, such as in a motor or MG set, will not last long if subjected to ________ loads.

• A. radial
• B. angular
• C. axial
• D. tensile

Answer: (B)

Radial ball bearings are built to support loads that act perpendicular to the shaft. When a bearing of this type sees angular loading—loads that have an axial component in addition to the radial one—the thrust forces on the races increase. That axial component is not well supported by a pure radial bearing, so the contact stresses rise, wear becomes uneven, and the bearing life drops quickly. In other words, these bearings don’t handle combined radial and axial loading well, so angular loading severely shortens their life. If axial loading is needed, a bearing designed for thrust or angular contact loading would be used instead. Tensile loading isn’t typical for bearing elements in this context and isn’t how these bearings are meant to be loaded.