Flotation, Compaction Key in Tire Selection

Flotation, Compaction Key in Tire Selection

Saturated soils mean doing some research ahead of spring work.

Winter has finally passed and now farmers throughout the Midwest are left dealing with the aftermath. Saturated ground conditions are common across the region following significant rainfall last fall and unprecedented snowfall this winter. The potential for saturated field conditions limiting fieldwork this spring is high. Tire maintenance and selection are going to be major factors this spring in helping farmers complete spring fieldwork.

"Flotation and compaction will be key this spring," says Bill Campbell, president of Titan Tire Corporation. "The saturated soil conditions are going to create soft spots throughout fields and the risk for compaction could be higher this spring. Farmers need to ensure tire pressures are set correctly and they may want to consider switching to taller or wider tires that offer more flotation to help reduce compaction issues."

Switching tires is a major decision and requires some research to make the right choice. Farmers in narrow row applications may want to consider adding duals or triples as a way to create more flotation. This will help spread the load over a wider footprint. While many farmers will add duals or triples to the back axle, adding duals to the front of mechanical front wheel drive (MFWD) is also becoming quite common.

Adding duals or triples puts more tires on the ground, which dissipates the load evenly across that axle and allows the tractor to carry the same load as a single tire would, but with lower air pressure, which will positively affects soil compaction.

"Tire air pressure also plays a role in soil compaction," says Campbell. "The ground pressure exerted by the tire will be 1 to 2 pounds higher than that of the tire psi. So if you run your tires with 20 psi, then the ground pressure from that tire will be approximately 22 pounds at contact. You can reduce the ground pressure by lowering your air pressure."

Larger tires provide more flotation

To better understand how to enhance flotation, it's important to know what affects the load a tire can carry. It's pretty simple - air pressure is what carries the load of the tractor. So a larger tire chamber means the tire will carry the same load with less air pressure. A lower tire pressure lowers the ground pressure leading to reduced compaction.

For spring tillage, farmers can select a wider, higher flotation tire. These tires are designed with a wider profile that helps the tire maintain flotation in wet field conditions, but also offers enhanced traction and cleaning due to the wider and deeper lug pattern.

With the move to narrow rows from 30 to 22 inches - selecting a wider tire for flotation really isn't an option. That's were taller tires come into play.

Five years ago, the most popular rear radial tractor tire on the market was an 18.4 R38 (480/80R38). That tire had the capacity to carry 7,150 pounds at 23 psi. So if you want to stay with an 18.4 cross section, the industry now offers this nominal tread width in 42-, 46- and 50-inch-tall tires. If you decided to go with a 50-inch tire, it would have the ability to carry 9,650 pounds at 35 psi. However, if air pressure is critical, you can carry the same load as the 38-inch (7,150) pounds at 21 psi. It pays to make comparisons and look at all the options available.

"A taller tire will also provide a longer footprint putting more rubber on the ground," says Campbell. "This in turn will stretch out the tread pattern that you're putting on the ground, helping to reduce compaction and providing more flotation at a lower air pressure. It's also important to note that moving to a taller tire requires an investment in new wheels as well - it's not just the cost of the tire, but the benefits can far outweigh the additional cost."

Weekly tire maintenance is a must

Would you go to the field without checking your planter to make sure it's properly adjusted? Of course not; the planter is probably the most important piece of equipment on your farm. Farmers should have that same view regarding their tractor tires. It's common for farmers to ignore their tires, but slight adjustments can make a significant impact on compaction and tractive effort under load. So before you begin fieldwork this spring, it's important to inspect your tires for any damage, and check air pressures.

First, conduct a visual inspection of the tires and look for potential stubble damage, cuts or any other field hazard that may have caused damage to the tire. If a tire is worn, rather than trying to squeeze out another season, the farmer should seriously consider purchasing new tires. Trying to push a worn tire can be a big mistake when it's important to get the crop in the ground. A worn tire will have limited cleaning ability, which in turn will reduce traction. If you find defects, it's important to contact your local, independent tire dealer and work with them to resolve any issues.

Second, check air pressure levels in all tires. As we pointed out earlier, air pressure is critical to limiting compaction and affects overall traction and ride. Campbell recommends farmers check tire air pressure levels on a weekly basis. Temperature fluctuations in the spring will have a major impact on tire pressures.

"The old rule of thumb is for every 10 degrees in temperature drop, you're going to lose approximately 1 psi of air pressure in your tire," says Campbell. "Now when the air in the tire starts to heat up and the outside temperature becomes warmer, some of that loss will come back, but not completely. That's why we recommend checking air pressures on a weekly basis. It's a simple step to help limit compaction and make sure your tires are in optimum working condition."

Considerations before buying new tires

Whether you're replacing a worm, damaged tire or moving up to a taller tire to enhance flotation and limit compaction, there are a number of considerations in selecting the right tire for your application.

If you are running bias tires, a consideration is upgrading to radial tires. Radial tires have been proven to offer enhanced traction, longer life, improved fuel economy and a smoother ride. Farmers running a R1 tire may want to consider upgrading to a R1W which offers a 20 to 25 percent deeper lug and will provide better overall traction and cleaning characteristics especially in heavy tillage applications. 

Purchasing a new set of tire is a major investment. However, making this decision sooner rather than later could save you hundreds of dollars. Raw material - natural rubber and oil - costs are unstable and rising. The tire industry recently increased prices and another price jump is anticipated yet this year.

No matter the situation, take the time you need to research the options. Selecting new tires can get confusing at times, and that's where a quality independent tire dealer can help walk you through the options and make recommendations based on your needs.

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