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Caster Wheel vs Assembly Rating

Compare the wheel rating with the bracket, axle, and mounting rating so the whole caster is limited by its weakest part rather than by its most impressive number.

A caster is an assembly, and its rating is the smallest number on the datasheet. Enter the wheel, bracket, axle, and mounting ratings with the load the caster will carry, and the calculator returns the utilisation of each part and identifies the component that governs.

On a swivel caster the raceway is often the real limit and is not a separate input here; treat it as part of the bracket rating. The comparison also assumes the four figures were quoted under comparable conditions, which is the manufacturer’s statement to make rather than this tool’s to assume away.

Inputs

Component ratings and applied load

Range: 50–40,000 lb

Range: 50–40,000 lb

The forged or stamped fork that holds the wheel. Often lower than the wheel rating on economy casters.

Range: 30–40,000 lb

Use the published bearing capacity, or the axle thread and hub rating if the bearing is unrated.

Range: 30–40,000 lb

The plate, bolt pattern, or stem that carries the load into the equipment. Bolt pull-through and plate bending usually govern here.

Range: 10–60,000 lb

Result

Real assembly rating (weakest part)
600
Utilization of the assembly rating (%)
108
Which part governs
The bracket governs. The wheel can take more load than the fork that carries it, so buying a bigger wheel on the same bracket adds nothing.
Verdict
Overloaded as an assembly, even if the wheel alone looks adequate. The governing part will fail first: change that part, not the wheel.

What to check

  • Read all four ratings from the same datasheet revision.
  • Treat the raceway as part of the bracket rating on swivel casters.
  • Check side-load suitability separately where the caster will be pushed sideways.

Related calculators

Assumes the four ratings are quoted under comparable conditions, and a wheel rating from a rolling test is not strictly the same kind of number as a plate rating from a static bend test. Side load is not modelled, and the swivel raceway is not a separate input, although on a swivel caster it is often the true limit and should be treated as part of the bracket rating.