If tires had emotions, they'd probably feel overworked, abused and under-appreciated. Few vehicles or pieces of equipment work without them, so they're obviously important. And yet, we often ignore them until there's a problem. Like any other part of your equipment, however, tires benefit from regular maintenance. Here's a look at some of the ways you can get more mileage from your tires and avoid costly downtime.
How often do you actually check pressure? Most people wait until they can see that tires are low on air before refilling them. Tires often don't appear obviously under-inflated until they are well below the recommended pressure. Use a pressure gauge regularly. Make it part of your regular maintenance checks. And remember that over-inflation is a problem as well as under-inflation.
Be sure to have a good-quality pressure gauge on hand. Don't rely on service station or “freebie” gauges given away as promotional items. These may be inaccurate.
Pressure is temperature-sensitive, so regular checks help you adjust to seasonal changes. Pressure can vary about 1 psi for every 10°F change. This may not sound like a lot, but consider the difference in temperature between a winter day and a summer day, and you can see that this could make a significant difference.
This reasoning also applies to tires that have been driven. Recommended pressure is based on cold pressure, meaning that the tire hasn't just been driven. This is when you should check pressure.
The benefits of proper inflation are several. First, you get better fuel efficiency if your tires aren't under-inflated. Second, tires will wear more evenly when properly inflated. By contrast, over-inflated tires will wear proportionately more on the center of the tread (see illustration, page Contractor 15). This also reduces the amount of tread making contact with the ground or pavement, reducing traction.
Traction is a reason why many equipment operators reduce tire pressure in grounds equipment below the recommended psi. However, Don Kubly, a tire expert with Gempler's, suggests this is not such a good idea. True enough, letting pressure out will increase traction, says Kubly, but doing so will cause the sidewall to flex more than it should. This can lead to separations within the tire, resulting in to premature failure. “You don't see it on the outside, but it's happening inside,” explains Kubly.
Another possible drawback of improper inflation is that the equipment will be a slightly different height due to a changed tire profile, which can affect ground speed. So, for example, if you know your sprayer travels X mph at a certain throttle setting and in a certain gear, letting air out for additional traction can alter the vehicle's speed, possibly throwing off calibration.
Rotation, balancing and alignment
Over-the-road vehicles require periodic wheel balancing, rotation and alignment. This type of maintenance does not apply so much to grounds equipment, but is critical for trucks and cars. Owners' manuals almost always tell you how often to perform these adjustments or advise that you at least check to see if they're needed. If this maintenance is not performed as suggested, the result will be uneven wear and premature tire replacement, as well as reduced fuel efficiency.
Owners' manuals usually provide specific tire-rotation schemes (see illustration, page Contractor 4). These will vary depending on whether the spare tire is included in the rotation, and on whether the tires are directional, as many are. Be sure not to neglect this simple maintenance item. Typical rotation intervals are in the range of 5,000 to 6,000 miles.
Misalignment is usually easy to spot because the vehicle will shake or pull to one side. This usually causes uneven and, often, conspicuous tire wear one side of the tire (see photo, page Contractor 4). Check alignment as directed in the owner's manual, or whenever tires are serviced.
As with misalignment, tires that are out of balance are easy to spot due to shaking during operation. Tires should be balanced after rotation, after a flat is fixed or when new tires are installed.
Rotation, balancing and alignment are not merely for increasing tread life and fuel efficiency. These can be considered safety matters. Tire failures at high speeds can be fatal, and many, if not most, such failures can be prevented if tires are properly maintained.
Storage and protection
Certain environmental factors can affect tire rubber in detrimental ways. Sunlight (especially UV light) as well as heat can cause rubber to degrade. So can ozone. For this reason, indoor storage is preferable to outside storage. If you must store equipment outside for the long term, the simple step of draping a tarp or something similar over the tires can significantly reduce environmental effects. Certain products that claim to prolong the life of rubber may indeed do so, in part because they act like a sunscreen, preventing harmful UV rays from degrading the rubber.
Kubly explains that grease, oil, acid and other chemicals may soften the tire rubber. “It's not something that can destroy a tire overnight,” says Kubly, but it can make a difference in the long term. Therefore, be sure to wipe off any such materials if they come into contact with tires.
The details of repairing tires are beyond the scope of this article. Because of potentially hazardous situations, only qualified technicians should repair tires.
Tire sealants are commonly used preventively in grounds equipment to combat frequent punctures from thorns, sticks and other objects. Though sealant cannot prevent every flat, it can be an effective method of preventing extensive downtime from minor punctures.
Retiring your tires
All tires eventually wear out. Over-the-road (OTR) tires are regulated in most states so that any tread less than 1/16 inch is illegal. (You've probably heard of the penny test, but it's best to keep a tread gauge on hand.) You also may see tread-wear indicators on worn tires. These show up as bars extending across the tread, indicating that you should replace the tires as soon as possible.
With grounds equipment, no similar tread standard exists. However, it should become apparent that you need to replace tires when you can no longer achieve adequate traction. This can, of course, show up as spinning tires, but it also may result in tires (the turning wheels) that are hard to turn and slide sideways a bit during turns.
Serious sidewall damage or large tears in the tread may necessitate tire replacement before the tread actually wears out. Unfortunately, it happens. The most important point to be made here is that you should not try to repair a tire that legitimately needs to be replaced. This can create dangerous situations for both the tire repair technician as well as the vehicle operator once the tire is back in service.
One factor that may tip you off to the need for new tires is an increase in punctures. The thinner the tread, the easier it is for thorns, etc., to pierce the tire.
Use proper replacements
Kubly asserts that you should always stay with same size of tire, a rule not always adhered to. “You can go with a wider or higher profile tire on the same rim. But this can cause the tire bead to not seat correctly. If the fit is not perfect, you can get excessive wear or leaks.” This can also affect ground speed, which can be important for the reasons cited above.
Kubly also states that you should never put the wrong type of tire onto equipment. For example, don't put an ATV tire on a mower, even if the size is the same.
TRAINING AND TIRES
Equipment operators should learn operating habits that reduce tire wear and damage:
Take turns slowly, especially on pavement surfaces, which can wear tires much more quickly than turf surfaces.
Go over steps, curbs and other obstacles slowly, so as not to damage the tires. Better yet, avoid them altogether when possible.
Check tire inflation daily as part of a morning walk-around.
Never drive on a flat tire, even for a short distance.
Be observant of tire performance. If traction is lacking, pressure may be too high or the tread may be wearing out. If turns become difficult, inflation may be low or the tread may be worn on the turning wheels.
Avoid areas with glass, metal, large rocks or other materials that could tear or cut tires.
Regular visual inspections and pressure checks should be a mandatory part of any maintenance program. Make the operator responsible for cursory daily checks, and implement a more thorough inspection as part of scheduled weekly maintenance.
Gempler's Don Kubly recommends using software designed for maintenance tracking and scheduling as an effective method of ensuring that proper maintenance occurs. Include tires in these computer-tracked maintenance regimes.
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