I've heard this meaning from some of the old timer truckers.
A 1/2 ton truck can have an additional 1/2 ton of weight put on it's front axle. Likewise the 3/4 and 1 ton trucks can have an additional 3/4 and 1 ton of weight applied to their front axles. While the rear axle is designed to carry the majority of the weight, a small amount of it will be transferred to the front axle as well. Proper loading of a truck (particularly an 80,000 lb GVW semi) will adjust the load position (using a sliding fifth wheel on a semi) so that you have not overloaded the front or rear axle.
My 1958 1 ton, was likely sold as a cab and chasis to Knapheide where they attached the grain bed, sold it to a farmer... and 55 years later ends up in my hands. My front axle is rated at ~4000 lbs and the rear axle is rated at 7600 lbs. Documentation from other models (not the cab and chasis) tells me that the GVW is 9600 lbs. These numbers don't add up! Maybe the axles are stronger than the frame? Maybe they didn't want to have a 1 ton truck that could hold nearly what the 1.5 ton truck could hold?
Another interesting tid bit about my truck. I don't have a stated GVW. Chevy never stated one for the Cab and Chasis. There is not a GVW number stamped on my original data plate inside the door. Knapheide didn't state a GVW after manufacture for the truck. I wonder what would be the first thing to break if I started loading it up?
