Any discussion of a forklift’s capacity to lift weight must also consider the load center and load moment. As seen above, forklifts are rated not just for a specific weight but also for a particular load center. This is because too much weight on the forks could tip the forklift over — a hazardous occurrence. Weight X is lifted easily when positioned with its center mass close to the fulcrum (in a forklift, the front wheels’ axle), yet can tip the forklift over if the load center is shifted too far toward the fork tips.
Calculation of load moment is Load Moment = Weight x Distance. So you can see that the same 5,000 lb weight from above has a load moment of 120,000 inch-pounds when multiplied by the 24” load center, but the load moment climbs to 180,000 inch-pounds when the load center moves to 36”. Essentially, the load moment measures the overturning force applied to the forks of the lift.