In industrial applications, most equipment is not stationary. Movement introduces vibration, impact forces, surface irregularities, and uneven weight distribution. For this reason, selecting a caster based solely on static load capacity often results in underspecification and early failure.
Static load rating refers to the maximum weight a caster can support while completely stationary. There is no rolling motion, no impact, and no dynamic stress applied to the swivel assembly or wheel bearings.
Static ratings assume:
Static load rating is relevant for equipment that remains stationary for extended periods, such as fixed machinery or storage units.
Dynamic load rating represents the maximum weight a caster can safely support while in motion. This rating accounts for real-world industrial forces including rolling resistance, vibration, impact loading, surface transitions, and frame flex.
For nearly all mobile industrial applications, dynamic load rating must be used for engineering calculations.
| Condition | Static Load Rating | Dynamic Load Rating |
|---|---|---|
| Movement | No movement | Rolling / Active movement |
| Shock Impact | Not considered | Included in rating |
| Floor Irregularities | Assumes level surface | Accounts for uneven surfaces |
| Typical Use Case | Stationary support | Industrial mobility |
When equipment moves, forces multiply. Wheel deformation, bearing stress, and swivel race impact increase significantly compared to stationary conditions. Selecting casters using static ratings alone can lead to:
In practice, uneven floors and equipment frame flex cause three casters to carry the majority of the load at any given moment. Engineering calculations should never assume perfect four-point weight distribution.
This is why safety factors are applied when determining required dynamic capacity.
| Application Type | Recommended Safety Factor |
|---|---|
| Manual Indoor (Smooth Surface) | 1.25 – 1.35 |
| Manual Outdoor (Rough Surface) | 1.5 – 1.8 |
| Powered Equipment | 1.8 – 2.0+ |
| High Shock / Impact Environments | 2.0+ |
Load per Caster = (Total Equipment Weight ÷ Number of Casters) × Safety Factor
Use the CasterSpec™ Load Calculator to determine the proper dynamic load capacity required for your application.
Applications involving dock plates, steel fabrication, manufacturing transitions, and high-impact movement require reinforced rig construction. In these cases, kingpinless heavy-duty casters are often recommended to resist shock loading and pivot stress.
View available kingpinless industrial casters designed for high-impact environments.
Dynamic load rating should be used for any application involving movement. Static rating applies only when the caster remains stationary.
Movement introduces vibration, impact forces, and uneven weight distribution, increasing mechanical stress on the wheel and swivel assembly.
Divide total equipment weight by the number of casters and multiply by the appropriate safety factor based on application type.
Return to the full Industrial Caster Selection Guide for complete engineering methodology.
