Am I reading this right? (Receiver capacity)

Your axles are rated differently to allow you to put different weights in your vehicle. For example, a load of gravel over the rear axle will put all the weight there, maybe even unload the front. But then some people pull trailers, and put sizable boats up over the cab.... and that would load the front axle.

Rear axle weights are usually twice the tire capacity and are printed on the label when the truck went off the assembly line. Different tires and wheels would have a different rear axle rating.