How to Calculate Axle Weight on a Truck

When loading a truck or designing for vehicular capacities, not only must the overall weight of the vehicle and its cargo -- even if that cargo is people -- be considered, but the individual loads on each axle must be calculated. Limits on axle loading will prevent steering difficulties, if heavy loads are imposed on the steering axle, and help alleviate maintenance problems resulting from overloaded tires or drive systems requiring early replacement because of overloading on main or drive axle systems.

Things You'll Need

• Calculator

Instructions

1. Go to a certified scale before the vehicle is loaded and have each axle weighed separately. This will tell you what the axle loading is for the vehicle while empty.

2. Use a calculator to subtract the empty weight of each axle from the maximum allowable load from each axle.

3. Use the following formula to calculate loading for front and rear axle weights, where where LCf = load capacity of the front axle, LCr = load capacity of the rear axle, Lf = distance to load center from front axle and WB = wheelbase of the vehicle: (LCf)(Lf) - (LCr)(WB-Lf) = 0.

Tips & Warnings

• Calculate the axle weights for tractor trailer rigs by making separate calculations for the tractor and trailer. Each double axle is treated as a unit, rather than as separate axles.

References

• Truck and Bus Engineering

Resources

• Read this Article in Spanish
• Society of Automotive Engineers