Beating the heat
Summer has officially arrived for most of the continent, so it's time for fleets to take the necessary steps to prevent heat-related damage to tires. While tremendous heat buildup is inevitable in this time of year, if it's managed properly, there should not be any negative effects on tire life or performance.
The single most important aspect is to maintain proper inflation pressure on a daily basis. Drivers are required to check tire pressure on every pre-trip inspection, but too many still rely on a tire thumper or the old boot-o-meter. Neither are reliable or accurate so anything short of placing a calibrated gauge on the end of every valve stem will result in an increased number of emergency road service calls due to flat or failed tires.
It's equally important to ensure that dual tires are properly matched so that one tire is not supporting more weight than the other. The official guideline is to ensure that there is no more than a 1/2-in. difference in the diameter between dual tires. But tire squares and similar measuring devices are about as rare as falling diesel fuel prices, so the easiest way is to make sure that any difference in tread depth between dual tires is less than 4/32 of an inch if they are the same brand and tread design. It's not foolproof because there are slight differences in overall diameter between manufacturers, but if the tread depth between duals is within the 4/32 range, the tires should be close to matched.
Another factor that will impact the amount of heat generated is the condition of the brakes. Improperly adjusted brakes create excessive friction in the drum and hub, which eventually works its way to the tires. In the worst-case scenario, the heat becomes so severe that the tires can actually catch fire shortly after the vehicle has been parked. As strange as that sounds, the airflow around the hub and drum while the vehicle is moving cools the components. Once the vehicle stops, the heat just continues to rise until it reaches the point where the tire catches on fire. Hopefully, the driver will notice if the brakes are locked or frozen, and the only problem will be a couple of tires with flat spots.
Excessive heat can also be caused by improperly installed or lubricated wheel bearings. Once again, the airflow around the hub during operation usually provides sufficient cooling, so the real danger doesn't start until the vehicle stops. If the driver is observant enough to catch it after being made aware of bearing work prior to the trip, the worst-case scenario is typically burned beads. If the driver has no idea whether the bearings (or brakes) were recently serviced, the beads won't be the only things burned.
With tire prices continuing to escalate, fleets must take every possible step to protect new tires so they can be retreaded and retreads so they won't have to be replaced with a new tire. Summer is by far the most stressful season for tires, but good inflation pressure maintenance and pre-trip inspection programs are the best tools for combating the intense heat that affects tires this time of year. And while maintenance personnel must be reminded to exercise extreme caution when adjusting brakes or servicing wheel bearings, it's also important to communicate with the drivers so they can be on the lookout for any problems on the first trip following these types of service.
