Definition: Static load rating is the maximum load a caster can support while stationary under ideal conditions.
Key distinction: Static load ratings apply only when equipment is not moving and loads are evenly distributed.
When static load rating applies
Static load ratings are valid only in applications where equipment remains stationary for extended periods.
- Parked equipment or fixtures
- Temporary staging platforms
- Level floors with evenly distributed loads
- No rolling, turning, or shock forces
Important: The moment equipment moves, static load rating no longer applies.
Typical static load rating ranges
| Duty class | Typical static load per caster |
|---|---|
| Light duty | 200–500 lb |
| Medium duty | 500–2,000 lb |
| Heavy duty | 2,000+ lb |
Static ratings are typically higher than dynamic ratings due to the absence of motion and impact forces.
Limitations engineers must understand
- Static ratings assume even load distribution
- No allowance for shock or vibration
- Does not account for rolling resistance
- Not suitable for mobile equipment selection
Reality: Many caster failures occur because static ratings are incorrectly used for moving equipment.
Common engineering mistakes
- Selecting casters based solely on static load capacity
- Ignoring dynamic forces in mobile applications
- Assuming higher static rating equals better performance
- Failing to account for uneven floor conditions
FAQs
Is static load rating higher than dynamic?
Yes. Static ratings are higher because no motion or impact is involved.
Can static load rating be used for carts?
No. Carts and mobile equipment require dynamic load rating.
Why do manufacturers list static ratings?
They are valid for stationary applications and storage scenarios.
Does wheel material affect static load?
Yes. Harder materials typically support higher static loads.