Monitoring tire pressure is a key element to proper vehicle maintenance for fleet drivers. And now that summer has arrived, monitoring tire pressure should be an even bigger focus due to the number of tire blowouts that occur as a result of the summer heat.
But this doesn’t mean that blowouts occur only when summer arrives. Fleet drivers should keep proper tire evaluation in mind year-round, which begins with making sure the tires of a vehicle are at their ideal operating pressure.
“If the air pressure is correct for the load, then the weather should have a minimal effect on the condition of the tire,” said Kevin Rohlwing, senior vice president of training for the Tire Industry Association. “However, when a tire is underinflated and therefore overloaded, hot weather increases the amount of internal heat that builds up as a result of the overflexing.”
Keeping Tires Healthy
Tire tread separation occurs when internal heat reaches its limits, and the bonds between the belts of the tire and the casing break down. This could lead to the deterioration of the tire’s belt package or the separation of the belts from the casing of the tire.
Any tire that operates with less than its recommended operating pressure — 80% — is more likely to fail in higher temperatures. However, a tire can still fail in colder temperatures, said Rohlwing. If the tire has not reached its recommended operating pressure, it could still fail, but would take longer because the cold air flow keeps temperatures down.
“A few pounds underinflated in the winter where all of the driving is local won’t experience as much degradation as the same tire in hot weather about to embark on a long highway trip,” said Rohlwing. “Underinflated tires on fully-loaded vehicles during summer road trips can experience enough degradation to fail within hours if the pressure is too low.”
A tire that is inflated properly can flex enough to adapt to changes in the road surface, but not so much that it generates excessive levels of heat, according to Rohlwing.
Because tire pressure is so important, a fleet driver needs to check his or her tires daily. However, the best time to check a tire is when it has reached its ambient temperature. This is when the tire is the same temperature as the air. The best time to check inflation is first thing in the morning, which is when ambient temperatures are lowest, said Rohlwing.
In the heat, it can take up to three to four hours for the tire to reach its ambient temperature after a vehicle has operated for several hours.“If inflation pressure is checked hot, the pressures should be higher than the recommended level,” said Rohlwing.
When the tire has reached its ambient level and a fleet driver has determined that a tire needs to be filled to its recommended operating pressure, he or she can then inflate the tire appropriately. But, as with monitoring pressure, there are caveats to the inflating process.
“It’s a good idea to have some type of dryer or a way to limit the moisture in air lines to avoid inflating tires with moist air,” said Rohlwing. “Compressors should be drained more often and daily if necessary.”
If there is an excess of moisture in the air line, the rim of the tire can corrode and ultimately damage it.
Temperature is unrelated to the inflation process, Rohlwing noted. Improperly inflating tires possess risks in any kind of weather.