A wheel bearing is what lets the wheel spin smoothly around its axle. Caster wheels use several bearing types — ball, roller, tapered roller, plain bore, and precision — each with a different capacity, rolling resistance, and cost tradeoff.
Bearing type is a separate spec from wheel material — the same polyurethane or rubber wheel is often available with different bearing options, and the bearing choice mainly affects rolling resistance and load capacity, not floor protection.
High-cycle applications where rolling resistance adds up (less push effort matters at scale), and heavy loads where bearing type directly limits capacity.
Assuming a plain bore bearing is “good enough” at any capacity. Plain bore (bushing-style) bearings are the lowest-cost option but also the lowest capacity and highest rolling resistance — fine for light duty, not for heavy or frequent use.
Which bearing type is best?
Depends on the application — precision and tapered roller bearings roll easiest and handle the most load, plain bore bearings cost less but roll harder and carry less.
Can I upgrade the bearing on an existing caster?
Sometimes, if the wheel and hub design support it — check with the specific product listing or call for guidance.