5-Ton Standard 4WD Forklift (2-Stage Mast, 3m Lift Height) Load Capacity Specification

Document No.: FL-5T-4WD-3M-2025  

Applicable Configuration: Kaystar rough terrain forklifts 5T Rated Load, 4WD Drive, Standard 2-Stage Mast, Max Lift Height 3000mm  

Compliance Standards: GB/T 5140-2021, ISO 22915-4:2020

1.Load Capacity Table (At 3m Lift Height)

Key Principle: As the Load Center (LC) increases, the Safe Working Load (SWL) decreases. The 4WD system only enhances terrain adaptability and does not change the load attenuation rule.

Note 1: All load values include a 10% dynamic safety margin per ISO 22915-4, to accommodate minor ground unevenness or load movement.  

Note 2: The 4WD system improves traction on rough terrain (e.g., mud, slight slopes). For slopes >3°, reduce load by an additional 15%.

2.Core Load Limitation Principles

1. Moment Conservation PrincipleThe forklift’s load capacity is determined by the load moment (load × load center distance). The maximum allowable moment is 25,500 Nm, to prevent exceeding the mast’s structural limit and counterweight balance capacity.
2. Structural Strength LimitAt 3m lift height, the standard 2-stage mast’s beams and cylinders are rated for 5000 kg (at 500mm LC). Exceeding this may cause mast deformation.
3. Stability BoundaryThe stability triangle of a 4WD forklift is identical to that of a 2WD forklift. When the load center exceeds 900mm, the risk of longitudinal tip-over rises sharply, so the minimum load is limited to 2700 kg.
4. Dynamic Load CorrectionIf lift/lower speed exceeds 0.8 m/s or the load is unstable, reduce the load by 20% to avoid inertial forces compromising balance.

3.Safety Operating Guidelines

1. Before operation, calculate the actual load center using cargo dimensions (for irregular loads, use the farthest CoG point). Cross-verify with the table to confirm SWL; overloading is strictly prohibited.
2. If the load’s CoG is offset by more than 100mm from the fork center, reduce the load by an additional 10% to maintain balance.
3. On uneven terrain (even with 4WD), avoid maximum lift height with full load. Lower the forks to 300–500mm above the ground before traveling.
4. For loads with protruding edges or unstable packaging, use additional securing straps to prevent CoG shift during lifting.