1997 Ford Aerostar Owner's Manual - Page 185

Gross Axle Weight Rating (GAWR) We have all seen a car or a truck that is loaded down in the rear and riding high in the front. This is a dangerous condition that usually means that the rear suspension components are under severe strain and that vehicle handling is impaired. There is more to carrying a load than just payload or GVWR. Your Safety Compliance Certification Label not only gives the GVWR, it also gives the Gross Axle Weight Rating (GAWR) which is the carrying capacity for each axle system. For trucks, the rear axle will be designed to carry more weight than the front. The rating is based on the carrying capacity of the lowest rated axle and suspension component as well as other factors. This is why it's so important to observe vehicle loading ratings. Overloading a vehicle punishes components and can lead to shortened service life or outright failure. The capacity of the tires is included as part of the axle and suspension system, which is to be considered when determining the lowest rated component. Tires are rated to carry a specific maximum load at a specific maximum tire pressure. Passenger car type tires when installed on light trucks and multipurpose passenger vehicles are rated at 10% lower load carrying capacity due to the differences in vehicle usages. The vehicle must not be loaded to both the front and rear GAWR because the GVWR will be exceeded. The GAWR of the front and rear axles exceeds the GVWR when added together to allow flexibility in fore and aft loading of cargo. 185