Hauling Heavy Loads
Overloading can have serious consequences in terms of safety. Too much weight for your vehicle’s suspension system can cause spring, shock absorber or brake failure, handling or steering problems, irregular tire wear, tire failure or other damage. An overloaded vehicle is hard to drive and hard to stop. Brakes can completely fail, particularly on steep hills on an overloaded vehicle. A combination of size of the tire and the corresponding inflation pressure determine the load that tire can carry safely. Overloading the truck, with under inflated tires, can be perilous. Abnormal tire flexing takes place due to overloading. This generates excessive heat within the tire that may exceed the tire’s capacity and lead to tire failure. The air pressure enables a tire to support the load, therefore proper inflation is critical.
Trucks can be loaded in many different ways; air pressures must be determined from the actual loads (determined by weighing) and taken from the load and inflation tables provided by the tire manufacturer. However, they should never exceed the tire limitation for load or air pressure. If you discover that your tires cannot support the actual weights, lighten the load or install tires with a higher carrying capacity.
It should be noted that installing tires with a higher carrying capacity only solves the problem of tire overload. It has no effect on the overloading of other components (i.e., rims, axles, shocks, or bearings). Rims may not be capable of withstanding the higher pressures necessary to support the load. If you decide to install a tire size other than that originally provided on the vehicle, care must be taken to ensure adequate load-carrying capacity and compatibility between the tire and rim. There is a danger of serious injury or death if a tire of one bead diameter is installed on a rim or wheel of a different rim diameter. Always replace a tire with another tire of exactly the same bead diameter designation and suffix letters.
If you have operated your vehicle with an underinflated tire, promptly have it removed from the wheel for a complete internal inspection to be sure it is not damaged. Tires driven even short distances while underinflated may be damaged beyond repair.
Tires should be inspected regularly for excessive or irregular treadwear, bulges, aging, fabric breaks, cuts or other damages. Remove any nails, stones, glass, etc., embedded in the tread to prevent damage. Even minor damage can lead to tire failure. Replace tires when the tread is worn to 2/32″ depth remaining in two or more adjacent grooves.
On vehicles with GVWR in excess of 10,000 pounds, federal regulations require that tires on the front axle be removed when worn down to 4/32″ depth. It may also be desirable to replace tires prior to wearing down to 4/32″ to improve traction or vehicle handling. If your tires show uneven wear, ask a serviceperson to check for and correct any misalignment, imbalance, or other mechanical problem involved. Check your tires frequently for scrapes, bulges, cuts, snags, or impact damage. Damage can occur to the inner portions of your tire without being visible on the outside. While driving, if you experience a sudden vibration or ride disturbance, or if you suspect that damage to your tires or vehicle has occurred, immediately reduce your speed or stop. Drive with caution or have your vehicle towed to the nearest vehicle or tire dealer to have your vehicle inspected.