1997 Ford Expedition Owner's Manual - Page 124
1997 Ford Expedition Manual
Page 124 highlights
Driving weight limit than the originals do not increase the GVWR or the GAWR limitations. In high altitudes, engines will lose power at a rate of 3% power per 1000 ft increase in elevation. A reduction in GVW and GCW is recommended for maximum vehicle performance. Remember to figure in the tongue load of your loaded trailer when figuring the total weight. Do not exceed the GVWR or the GAWR specified on the Safety Compliance Certification Label. Driving with a heavy load The total vehicle weight plus the total weight of passengers and cargo should never exceed the GVWR. The weight that the vehicle carries over the front and rear axles should never exceed the GAWR for the respective axle. The weight limits of your vehicle's tires affect the GVWR or GAWR limitations. Using tires with higher weight limits than the original tires will not increase the GVWR or GAWR of your vehicle; using tires with lower weight limits may lower the GVWR or GAWR of your vehicle. 125