Caterpillar Performance Handbook, January 2017, SEBD0351-47

Weight Distribution

On-Highway Trucks

WEIGHT DISTRIBUTION The first step in spec’ing a Truck is to understand how the load is distributed on the Front and Rear Axles. The load is defined as the Maximum expected weight of a fully loaded Truck. That includes the Driver, Fuel, Fluids, Payload, and Truck Body. Once the axle load- ing is known, it’s possible to begin selecting the Frame, Engine, Transmission, Axles, Suspension, Tires, etc.

Axle Loading Due to 5th Wheel (omit if using a Body) Front Axle Load = 5th Wheel Load × (A/WB) = _______ lb Rear Axle Load = 5th Wheel Load × (B/WB) = _______ lb Axle Loading Due to Forward Mounted Loads (Winches, Plows, etc.) Front Axle Load = Attachment weight × (C + WB)/ WB = _______ lb Rear Axle Load = – Attachment weight × (C/WB) = –_______ lb Negative

Center of Payload and Body or 5th wheel location

Center of Tandem Axle

Attachment Weight

Start by identifying where (in relation to the axles) the load will come onto the truck. This can be a 5th wheel location, or the center of gravity of the Body and Payload (like a Dump Truck or Tanker). See above illustration. Axle Loading can be found by adding up how major loads are distributed on each axle. Typical loads are the weight of the Truck Chassis, Body, Payload, or 5th wheel. Add up all the loads that apply for your Truck. Axle Loading Due to Truck Chassis (see “Chassis Types” tables in this section) Front Axle Load (Given by Caterpillar) = _______ lb Rear Axle Load (Given by Caterpillar) = _______ lb Axle Loading Due to Body and Payload (omit if using a 5th wheel) Front Axle Load = (Body +Payloadweight) × (A/WB) = _______ lb Rear Axle Load = (Body + Payload weight) × (B/WB) = _______ lb

Lift Axle Force*

*Max Lift Force = Lift Axle (Rated Capacity) – Weight of the Lift Axle. Example: Max lift force for a 13,200 lb lift axle is approximately 12,000 lb. The remaining 1200 lb is the weight of the axle, tires, wheels, and brakes. Axle Loading Due to Lift Axles* (see above illustration) Front Axle Load = – Lift Axle Force × (E/WB) = –______ lb Negative Rear Axle Load = – Lift Axle Force × (D/WB) = –______ lb Negative *If more than one (1) lift axle repeat as required. Total Axle Loading Front Axle Load = Add all Front loads that apply = ______ lb Rear Axle Load = Add all Rear loads that apply = ______ lb

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Edition 47 12-13