Before starting oft on vacation, be aware of the dangers of overloading your car-damage to tires and other parts, and handling problems.
Abnormal flexing under heavy loads causes the injury to tires. The edges of the tread can build up excessive heat and possibly start separating from the tire. Cords in the sidewalls can begin to snap, and once this starts, it will probably continue, even .after the load is removed.
An overloaded car is hard to handle, especially in emergencies calling for quick maneuvering. And the car's springs and shock absorbers may be strained to the point of actual damage.
The size of a tire, its ply rating or load range and the inflation pressure determine the safe load limits of a tire. The tire's maximum load capacity at a specified maximum inflation pressure is molded on the sidewall. One example might be: "Max. Load 1500 Ibs. @ 32 psi (pounds per square inch) Max. Pressure." If your car has four of these tires, the weight of the car and the passengers and baggage inside shouldn't exceed 6,000 pounds. But your owner's manual probably will tell you not to inflate the tires recommended for your car to the maximum pressure. So, in the case above, you would probably inflate the tires to about 30 psi (or slightly under), lowering the maximum load of the tires a few hundred pounds.
But what about the times when you need to haul heavy loads, especially for vacation trips? You can change to tires of the same size with a higher load range or to larger tires, or increase the pressure in each tire on your car (as long as you don't exceed the maximum).
One surefire way to avoid the worry of an overloaded automobile is to consider one of the heavier duty vehicles on the market, such as Chevrolet's Suburban. Actually a rugged truck that passes for a wagon, a properly equipped Chevrolet Suburban "Superwagon" can haul as much as 16,000 pounds, including vehicle, trailer, passengers, equipment and cargo.