Modern Tire Dealer has partnered with AG Tire Talk to provide answers to insightful questions that farm tire dealers have about farm tire technology. This is the next installment in our ongoing series, which is designed to help farm tire dealers better connect with their customers. A trending question, followed by answers, will appear in our Commercial Tire Dealer section every other month. For complete answers, click on www.agtiretalk.com.
Question: Why are implement tires pivoting from smaller 15- and 16-inch sizes to larger overall diameter and section widths of 22.5-, 26.5- and 30.5 inches? Why are higher void ratio directional tread designs gaining popularity (I-2/I-3 vs I-1). Will steel belt/all steel casing become the norm, and will segment ultimately become all VF Construction?
Dave Paulk, manager, field technical services, BKT USA Inc.: Implement tire designs and sizes continue to evolve and grow with the use of heavier equipment and wagons. The smaller 15-inch and 16-inch tires in a bias design have been used for a long time. Since there are still many implements that use these sizes, they aren’t going away anytime soon. The 15-inch and 16-inch sizes are still used in large numbers in bias tires.
With heavier equipment and road use more prevalent, small implement tires are now being designed using radial technology to carry heavier weights at highway speeds (30-45 mph). Many are made with steel belts and stubble-resistant compounds to help maintain the integrity of the tire and provide added puncture resistance in the field and on the road. Some are IF and VF rated and can be run at lower air pressures in the field to minimize soil compaction. BKT’s 19.5-inch and 22.5-inch I-1 radials are made with an all-steel construction. The 15- to 22.5-inch radial sizes are used on cultivators, planters/seeders, and a wide array of other equipment.
Although smaller implement tires are still widely used, larger implement tires (flotation tires) have become more common because of the weight of the equipment and wagons and the load carrying capacities needed. The larger sizes include 22.5-inch, 26.5-inch and 30.5-inch with a few sizes of 32-inch available. These are used on larger implements such as planters and on liquid and dry manure spreaders in dairy and feedlot operations. Some flotation sizes are used on larger hay balers. These tires are taller and wider to carry high loads on the highway at higher speeds. The wider width gives the tires good flotation when used in the fields and can spread out the weight of the load to minimize soil compaction.
While most of the smaller implement tires, bias and radial, are made in an I-1 design (rib type tire), the I-2 and I-3 designs (traction treads) have gained popularity in the larger implement (flotation) sizes. As opposed to the I-1 design, this tire provides some traction in the field if needed. When used in wet soil and on hills, the traction design limits the side to side (lateral) movement. With the correct air pressures, the tires generally wear well in highway use. Most are used in pull behind the tractor operations, although there are some self-propelled applications.
More of the larger implement radial sizes are steel belted or made with all steel construction. Both are used to maintain the integrity of the tire while in use. Both also add puncture resistance to minimize downtime and damage to the casing. The all-steel casings increase load carrying capacity as most are VF rated. VF technology and all steel casings are becoming more available because of the weight carrying capacity and speeds needed for applications using these tires. BKT makes both steel-belted and all steel radials in certain sizes.
Greg Gilland, vice president, global agriculture, Maxam Tire North America Inc.: The agricultural tire industry is in a constant flux that is evolving the boundaries of tire technology to achieve greater productivity and performance. Today’s farmers and growers are demanding improved tire solutions to increase their crop yields, reduce soil compaction and achieve better value to increase their profits. Over the last 20 years, we have seen the agricultural market move from bias ply tires to radial tire technology which has been accelerating year over year, particularly in the +100 HP type machinery including tractors, floaters, sprayers and combine harvesters.
Due to the perceived acquisition price difference, we still see a large percentage of smaller tractors below 100 HP primarily using bias ply tires versus adopting the growing radial product that delivers improved performance and value. Year over year, it is evident that increasing crop yields remain the number one priority for any farming operation, especially when using equipment above 100 HP. This increased demand for greater productivity has driven a rapid change towards adopting radial tire solutions beyond heavy equipment to support equipment or implements with solutions that can lower the high tire inflation pressures required to carry the respective loads. This has fueled the movement to adopt radial tire technology despite its higher acquisition price when compared to current bias ply tires. This evolving trend includes cultivators, diskers, rippers, planters and more primarily using smaller implement tires from 14 inches up to 18 inches. The growing use of radial tires on both towed implements and tractors provides greater traction in the field, which is achieving improved productivity, fuel savings, and most importantly, larger crop yields through reduced soil compaction.
When comparing the various types of Implement tires in the agricultural industry we find that each tread design has unique features depending on their function, tread depth, and soil working conditions.
In the North American market, I-1 Rib Tread pattern accounts for 85% of market demand. And in that pattern, size 11L-15 account for 65% of the overall demand, with 9.5L-15 and 12.5L-15 following with 15% and 10%, respectively.
The demand for greater productivity has rapidly driven a transition from the above bias sizes to equivalent radial tire solutions that have incorporated the use of both IF and VF tire technology. This technology shift is allowing new radial implement tires to carry 20% to 40% more weight at standard inflation pressures, or allowing the reduction of soil compaction by reducing the inflation pressure between 20% and 40%, which elongates the tread footprint and increases the flotation capability of the tires for each given load. In most instances, we are seeing the new radial tires being used at standard inflation pressures to carry heavier loads on larger implements, which improves farmers’ and growers’ productivity without compromising soil conditions.
Here's how the bias ply implement sizes have been converted to radial tire sizes:
- 11L-15: 280/70R15
- 9.5L-15: 240/80R15
- 12.5L-15: 320/70R15
In most cases, as the above radial sizes continue to evolve and adopt either IF or VF technology, we expect to see the utilization of both steel belts and steel casings to enhance the footprint and stabilize the heavier loads. The row crop applications in North America seem to dominate the primary and largest part of the implement tire market which overwhelmingly prefers the I-1 tread design over the more traction-oriented I-2 or I-3 tread designs. Currently, the radial portion of the implement market only represents about 10% of the North American total implement tire demand, however, that number continues to grow rapidly year over year as more farmers or growers adopt radial solutions. We may see the market shift towards more tractive designs closer to the I-2 or I-3 tread types.
Maxam Tire currently offers bias ply products with all three tread types for implements. As the implement tire market continues to evolve from bias tires, Maxam will bring radial solutions to the market that will meet or exceed our customers’ value expectations.
In addition to the evolution of bias ply implement tires to radial solutions, we are also seeing a migration from bias ply flotation sizes to radial flotation sizes in the larger diameter 22.5-inch, 26.5-inch, and 30.5-inch wheel seats to meet the heavier towed tanker or cargo hauler applications. This evolution is happening at a faster rate each year as European-type towed machinery continues to drive global changes toward these high-load / high-speed platforms. The largest shift in technology is the move from bias ply tires to radial steel-belted or fully steel constructed I-3 flotation tires that deliver improved traction using both closed and open shoulder designs that address the various soil conditions. In addition, we are seeing a demand for new radial tires that have heavier load-carrying capabilities with D-rated heat-dissipating rubber compounds capable of speeds up to 40 mph (65 kph). The transition to D-rated tires is being driven by the faster road speed required to move the equipment from the farm to the field or to the market.
As tractors continue to grow in horsepower, we fully expect the radial flotation tire sizes to evolve as well using VF technology to increase load-carrying capacity and corresponding speed capability to support the heavier or more powerful machinery. Maxam offers the current FlotXtra full steel construction tire with a closed shoulder non-directional design to meet the heaviest load application. The new directional steel belted AgilXtra features an open shoulder and improved self-cleaning tread design. Both the FlotXtra and AgilXtra deliver the high load and D-rated speeds the market is seeking in towed flotation solutions.
David Graden, operational market manager, agriculture, Michelin North America Inc.: Large farms are getting bigger and the number of people pursuing farming as an occupation is declining. In turn, the need to cover more land with fewer people, resources and time is driving the demand for larger machines and implements.
As a result of growing farm sizes, producers are finding it necessary to spend more time on the road between plots of land. Extended roading can cause heat to build up, creating breakdown of rubber compounds that can ultimately lead to a shorter tire life span.
Directional Tread Designs: To help alleviate this issue, tire manufacturers are designing implement tires with directional tread designs. This helps the tire to remain cool and slows the rate of wear by, both, creating flex and limiting flex in very specific areas of the rubber. As a bonus, engineered tread designs also add stability on slopes and stubble protection where it is needed most. Additionally, most tire manufacturers make tires for global needs. In most European countries, a producer is required by law to remove any soil or mud their machines release onto the road. For that reason, Michelin prides itself on designing tire treads to clean out mud quickly. Not only does this reduce the amount of road shoveling a producer is required to do, but it also significantly improves tractive capacity for those tires in powered positions.
Larger Sizes: One of the greatest challenges in the tire industry is machinery size. As machinery gets larger so does the need for tires that can carry the weight of those machines. From a tire perspective, the air chamber is what carries that weight and the rubber doughnut around it simply holds the air in place. The heavier the weight, the larger the air chamber and tire needs to be.
IF/VF Technology: In the early 2000’s, Michelin invented IF and VF technology. The purpose behind this was to increase carrying capacity without changing the tire size, due to limited space tires have to fit under machines. We did this by simply changing the flex point in the sidewall of that tire, which reduced the pounds per square inch on the tread and relieved the stress points on that rubber doughnut holding air in place.
Today VF type tires are becoming the standard. In fact, machinery size is growing so fast, larger tire sizes are needed in conjunction with VF technology simply to carry the weight demanded by these large machines.
Go Large & IF/VF: On a final note, as these large machines get larger, the yield damaging soil compaction is almost inevitable. For this reason, it is imperative to fit your machines with the largest VF tires allowable. Harper Adams University, in the UK, and University of Illinois Champaign Urbana have both proven VF tires set to the proper air pressure recommendations will reduce soil compaction and result in up to 4.3% improvement in yield of soybeans, corn and wheat. I am sure this additional yield will apply to other crops as well, but those studies have not been done yet.
For these reasons, tire technology will have to continue to evolve as machinery and farming evolves. The tires under your machine are the only thing standing between a properly operating machine and complete efficiency and performance.
Chris Neidert, marketing, training and development manager, ag, Trelleborg Wheel Systems: The implement tires today are not what your father used in the past. Implements have been evolving into larger sizes, heavier equipment and higher working speeds but still confined to be as small as possible. These challenges require the tires to also evolve and shift from traditional bias low speed construction to high speed, high load capacity, radial construction tires.
To maximize crop yields and transport times, it is necessary to invest in high performance machinery. With new technologically advanced implement tires, you can increase the load capacity of your equipment, such as manure tankers, big forage wagons and slurry tankers while protecting the environment.
You need tires that will ensure long durability and superior performance both in the field and on the road. In the field, the tire needs to have excellent flotation and self-cleaning features. On the road, it must deliver a comfortable ride and easy handling while providing increased stability and overall drivability.
This increase in load capacity requires stronger tire construction and a stronger bond between the tire and the wheel. Most of these tires require an increase angle of the bead seating area from 5 to 15 degrees to withstand these additional pressures and efforts. Tires and wheels designed with a bead angle of 15 degree can be identified as the rim diameter value ends in .5 (for example a 560/60R22.5) and designated as IMP.
Steel belts are used under the tread as part of the casing. This strengthens the casing to last longer and also flatten the tread face and make a wider footprint. This helps with tire wear and vehicle stability. The wider footprint increases flotation and reduces compaction, protects the soil and improves crop yield.
Let’s talk about the tread. Many implement tires are being produced with different tread patterns. The goal is to enhance tread stability which translates to vehicle stability when the vehicle is fully loaded. Some patterns could be called directional, which will help channel water out from under the tread.
In order to keep road debris to a minimum, various methods are used to keep the tread from loading up with mud. Reducing the amount of mud in the tread will translate to less road debris when the machine pulls out of the field and onto the road to go to the next field. Terraces in the bottom of the tread grooves help reduce mud buildup.
The latest technology development in implement tires is the offering of VF technology complementing the “conventional” radial construction. VF construction tires are designed to increase the load capacity at high speed, improving overall efficiency of the tire and implement. In field application it can be used at lower inflation pressure, delivering a wider and longer footprint and therefore reducing ground pressure and maximizing crop yield.
VF stands for Very High Flexion radial tire. The main advantage of this type of construction is it allows the tire to carry up to 40% more load than a tire “conventional” radial tire at the same air pressure and nominal speed. The ability to carry more weight will mean fewer trips, saving costs. If you are a manure tanker operator, this is a huge benefit.
This new generation of implement tires is being built with higher load indexes than in past years. The tire world has reacted to needing to be bigger and faster. The new implement tires are not your father’s implement tires.
