What are the two main types of bearings?

• A. Plain bearings and rolling-element bearings
• B. Ball bearings only
• C. Spherical bearings only
• D. Fluid bearings

Answer: (A)

The key idea is how the bearing surfaces contact each other. Bearings are usually grouped by contact method into plain bearings and rolling-element bearings. Plain bearings rely on sliding contact between surfaces, with lubrication reducing wear; they’re simple, rugged, and good for high loads or misalignment. Rolling-element bearings use balls or rollers between races, so the load is carried by rolling motion rather than sliding, which greatly reduces friction and supports higher speeds and precise motion. While there are other types like fluid bearings or spherical variants, the two main, broad categories taught are plain bearings and rolling-element bearings.