This rating is stated on the side of each tire. Suspension systems . Suspension systems have a manufacturer's weight capacity rating. Coupling device capacity . You must keep weights within legal limits.
States have maximums for GVWs, GCWs and axle weights.
Often, maximum axle weights are set by a bridge formula. This is to prevent overloading bridges and roadways. Overloading can have bad effects on steering, braking, and speed control. Overloaded trucks have to go very slow on upgrades. Worse, they may gain too much speed on downgrades.