Improper inflation, conversely, can have detrimental effects on the performance of both tires and vehicles. It also results in irreversible damage.
Underinflation causes abnormal tire deflection, which builds up heat and causes irregular wear. Overinflation causes tires to run hard, which increases road shocks and vibrations transmitted to the vehicle, and also causes irregular wear.
Because of summertime’s higher temperatures, the air pressure in a warm tire rises. Since air is a gas, it expands when it heats up and contracts when cooled.
Tire officials advise against bleeding air from a hot tire to relieve normal pressure buildup. Bleeding air pressure will result in underinflation because as the tire cools at the end of the shift or day, inflation pressure will drop.
The normal increase in pressure due to service conditions will be 10 to 15 psi, and this is allowable in a radial truck tire, they point out.
Checking and adjusting tire inflation pressure should always be done when tires are “cold,” say tire industry officials. That is, after a vehicle has been parked about three hours, before it’s been driven any more than a mile or before rising ambient temperatures or the sun’s radiant heat affects the pressure.
The officials recommend that tire inflation pressures be checked on a regular basis - at least once a week. This check should always be made with a calibrated tire gauge or a gauge that is checked periodically with a tire gauge known to be accurate.
Furthermore, they suggest the use of valve caps to help keep air inside the tires. If left uncovered, water and dirt can get down into the tire value stem can cause it to partially open, allowing air to escape.
Sealing metal or nylon valve caps, or quality “air-through” type caps, are the best, they point out.
One other key area to focus on when prepping vehicles for summer is the electrical systems, say officials with Kenworth Truck Company’s PremierCare Parts & Service group. www.kenworth.com.
They suggest taking the following measures:
- Check the alternator’s wiring to make sure the electrical wires haven’t come loose and moved within contact of fuel lines or any abrasive items.
- Inspect the vehicle’s batteries to ensure that they are firmly mounted in place.
- Check the integrity of the battery cables where they connect to the battery, and make sure the fasteners are secure.
- Look for corrosion at the battery’s terminal posts. If corrosion is present, clean it off and spray the connections with a battery protectant.
- Inspect the battery cables to assure they aren’t in contact with items that will wear through their insulation.
- Check the wiring to and from the engine’s electronic control unit to make sure it is in good condition.