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Follow the links below to learn more about the importance of proper tire inflation.

In the rush of the season, don't forget to take the vital steps needed for good tire maintenance. When inspecting your tires, there are many factors to consider. Firestone Agricultural Tire Division's manager of sales engineering, Len Wagner, recently gave us some tips for harvest-time maintenance of your farm tires.

Agricultural tires are designed to carry a specified load at a certain inflation pressure when mounted on the right rim. When these conditions are met, the deflection of the tires is in the ideal range, and optimum tire performance can be expected. If this combination of factors is altered, tire performance will more than likely be reduced. Taking a few extra minutes of inspection before hitting the field could save you time and money during this harvest season.

Traction in the field is often the key to an efficient day. A loss of traction can occur if the tread is worn abnormally. Isolated bubbles or bulges in the tread or in the sidewall because of separations can cause this abnormal treadwear. Damage can be a result of torn or missing drive lugs and deep abrasions in the tread/sidewall. Cuts or breaks that enter or expose the tire body should be promptly repaired to prevent moisture and foreign material from further deteriorating the tire. Finding these trouble spots early can deter you from having to purchase new tires.

Have you recently changed implements or upgraded to larger machinery? A major change in operating conditions is another reason to examine the performance of your farm tires. Increased implement weights, heavier loads pulled or greater usage on hard surfaces are all reasons to inspect your tires for damage.

Weather plays a major role in farming, and the elements can be especially hard on your tires. Long-term exposure to sunlight, ozone or electrical discharges may eventually cause tires to develop cracks. If those cracks extend down to the cord body, the tire should be replaced. According to Wagner, during road transport at high temperatures under heavy load, tires may get "hot to the touch." If this happens, Wagner recommends that tires undergo a 30-minute "cool-down."

A major culprit of lost time in the field is tire and rim slip. If repeated torque slippage of drive tires on the rim results in bead damage, replace the tire. In tube-type tires, it will create continued valve and tube damage; in tubeless tires, the tire will be prone to losing pressure.

"The three things that are vital to tire performance are inflation, inflation, inflation," said Wagner. Proper inflation for the load being carried is essential for optimum performance. A key to checking inflation pressure is using an accurate gauge. If a tire loses more than 20 percent of its rated pressure without explanation, the tire should be dismounted and the reason for air loss repaired. If the reason for air loss is unrepairable, the tire should be discarded.

Also, don't trust the inflation pressure on new tractors or when a new set of tires has been installed on an existing tractor. New tractor tires are normally inflated to 30 psi when shipped from the factory to minimize bouncing on the trailer. Dealers may overlook reducing the tire pressures or may not reduce the pressure to the proper level for the load on the axle. Plus tire changers often times inflate tires to 35 psi to set the tire beads on the rim.

To determine the correct inflation pressure on a tire you must first determine the axle load for your tractor by weighing your tractor on a scale. If a scale is not available, call your dealer to obtain the tractor's front and rear axle load. And be sure include any cast or liquid weights, tanks, loaders and the implement hitch weight.

When using heavy 3-point hitch mounted equipment, adjust rear inflation pressures based on the weight being carried on the rear axle with the implement raised. Return to the lower rear inflation pressures when using towed implements. For towed implements which transfer heavy vertical loads to the drawbar, (i.e., laser scrapers, grain carts) weigh tractor with maximum axle load and adjust inflation accordingly.

Next divide the axle load by the number of tires on that axle.

Using a tire guide obtained from your dealer, turn to the pages which list single, dual or triple load tables for your tire size. Begin at the left side of the table and move right until you either find the load for your tire or the next higher load. Move up the column to find the correct tire pressure.

Set all the tires on the axle to that pressure.

It is crucial to use an accurate tire gauge. Checking with a gauge that is off by just 2 PSI can lead to serious tire durability problems when setting tires at these lower pressures. Tires pressures fluctuate with air temperatures and should always be rechecked on a weekly basis.

Follow the links below to learn more about the importance of proper tire inflation.

Agricultural flotation tires, particularly 20" rim diameter tires used on fertilizer applicator vehicles, are frequently subjected to significant over-deflection (underinflation and/or overloading). This type of usage can damage the tire in ways that may not be immediately noticed and can lead to a tire failure. This is a particular concern if used on-road at higher speeds (maximum 30 mph).

Situation: Tractor jumps or bounces during field operation and creates a very uncomfortable ride and loss of traction. Operator may need to shift to a lower gear, reduce throttle or raise implement to continue operation.

1. How does tire pressure affect operating performance?

1. Determine the axle load for your tractor.

By David Elstein

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