Tire-related problems can render equipment useless in a heartbeat. Hazards on the jobsite - such as construction debris, potholes, etc. - can be relatively easy to identify. But don't overlook hazards that can occur before tires are ever placed in service, or when equipment is sidelined for extended periods of time. By properly handling and storing tires when not in use, you can help ensure they're fit for service when you need them most.
Start with where the tires are stored. If you have a choice, don't store tires outside, advises Cara Junkins, Titan. This exposes them to many environmental hazards that can speed degradation.
"There is a natural degradation that occurs over time. But certain factors speed up the process," she explains. "Tires are sensitive to heat, oxygen, ozone, and direct sunlight."
Manufacturers do add chemicals to rubber compounds to protect against these environmental hazards. But excessive exposure to ozone, for example, can cause weather checking, or ozone cracking that can show up as "crazing" or spider web-like cracks in the tread and sidewall areas of a tire. And atmospheric ozone generally increases during the winter months.
If you have no choice but to store tires outside, cover them with a heavy-ply, opaque, waterproof tarp. Be sure the tarp is large enough to keep out rain and snow that can pool inside the tire, or mount the tires onto wheels and inflate to 10% of operating pressure before storing. Any moisture that remains on the inside of the tire can promote rust when the tire is later mounted for use, notes Roger Best, Bridgestone Americas.
Storing tires outside can also pose problems in cold climates where snow and ice can freeze them to the ground and to each other, making them difficult to move. "You can more easily damage tires trying to break them free from ice," says Best.
Bring tires inside before mounting. "In lower or extreme temperature conditions, tire rubber can become brittle," says Steve White, Michelin, "so bring the tires up to shop temperatures before the mounting process begins."
Even indoors, there are hazards to keep in mind. As a precaution, be sure to keep an adequate source of extinguishing agent, such as water or carbon dioxide extinguishers and foam additives, in case of an emergency.
Keep tires away from ozone-producing equipment such as arc welding appliances, mercury lamps, electric motors, etc. "Tires can degrade from exposure to ozone," says White. "Ozone is a by-product of arc welding, so if arc welding is done in a shop, it's best that tires not be stored in that area."
Rubber can also absorb vapors from gas or lubricants. This can cause deterioration, so store tires in a dry area away from chemicals, petroleum-based products and oils/fuels. "A tire stored in a pool of solvent will begin to break down, since the rubber compounds on both the tread and sidewall contain some petroleum-based ingredients," says Tim Miller, Goodyear.
Tires should be laid perfectly vertical or horizontal, not leaning in any way. Place them on gravel or pallets to keep them off the floor and allow any moisture to drain away. Leave enough storage area around them for maneuvering and accessing the tires without the risk of hitting or rubbing against other tires, advises White.
Be careful when using a forklift to handle tires, since forks can easily cause punctures. "Bullnoze attachments can be a better option," says Best. "Also use straps instead of chains, because they spread the weight out over a larger area and minimize any high-pressure points, which can cut the bead."
With used tires, carefully clean and inspect the tires before sidelining them, and make necessary repairs before storage. "Repairing injuries that expose tire cord are especially important, because moisture can get into exposed cord," says Miller.
Take a load off
If you have equipment that has been parked for the winter or sidelined until the economy rebounds, you will want to ensure its tires are adequately maintained, as well.
"A little preventive care can help extend the life of tires," says Miller. "It's important to spend a little time with your tires prior to parking your vehicle."
If you're storing equipment for more than two months, it's best to place it on blocks to take the load off the tires. "When equipment sits on one part of the tire for an extended period of time, the tires can retain the shape they are stored in, causing what is called flat spotting," says Junkins.
Flat spotting is usually a temporary condition. But in severe cases, it can be permanent, which can hinder ride quality. A flat spot's severity is often a function of tire size, internal structure, load, ambient temperature and time. "Heavy loads and under-inflation can allow tires to deflect " says Miller. "And cold ambient temperatures make rubber compounds stiffer, increasing their tendency to flat spot.
"As tires roll, the constant deflection generates heat that makes the tires more flexible," he continues. "But once they are parked, the tire's footprint flattens as it grips the pavement. The longer a tire remains stationary, the bet"
If you can't block up a machine, move it periodically - about once a month - to help avoid flat spots. Also check the air pressure frequently to ensure it is maintained, since tires will lose pressure over time.
You can also raise the air pressure to avoid flat spotting during storage. Inflate them to the equipment's normal recommended inflation pressure plus 25%, says Miller, but don't exceed the wheel or rim manufacturer's maximum inflation capacity.
"By over-inflating the tires, you help buy some time against natural tire pressure loss, which is about 2 to 3 psi per month," he explains. "After you over-inflate, walk around the vehicle every week to make sure the tires are holding air. Slow leaks are hard to spot and can only be detected over time."
Before you put the equipment back into service, remember to set the inflation pressures back to the recommended level for the load being carried. Also inspect any stored tires prior to use.
"Check for physical damage from handling equipment and ozone exposure or chemical damage," says White. "By properly storing and handling tires, ozone, chemical and handling hazards can be avoided and tires can remain safe while not in service."