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: What’s the difference between all-steel and steel belt casings, what applications are recommended for each and what performance benefits do they provide?
Dave Paulk, manager, field technical services, BKT USA: There are differences in all-steel belt casings and steel-belted tires. Both have their advantages for different applications. All-steel casings have a steel belt instead of a fabric belt running from bead to bead in a radial design. In all-steel casings, there is generally one steel belt in the sidewall. Since steel doesn’t shrink or stretch, it allows for a consistently sized casing. The steel belt helps give the tire a flatter footprint and gives the carcass strength. This allows for higher inflation pressures, more load carrying capacity, lower rolling resistance, higher speeds and casing durability. All-steel casings have a higher ply turn-up around the bead and are easier to repair. Steel-belted tires are designed with fabric carcasses — like nylon or polyester — overlaid under the tread area. This provides a flatter footprint by making the casing rigid and has better penetration resistance. It also can reduce rolling resistance. The benefits of a flatter footprint include better traction, even wear, better handling and longer tire life.
Dana Berger, ag business development manager, Continental Commercial Specialty Tires: When it comes to tires, the carcass is the drop of water that causes a ripple effect. Without a strong, stable beginning, what could have been a masterpiece will fall apart in an instant. A tire’s carcass requires real attention to detail, as it is responsible for the damping and flexion of a tire. It must be constructed with quality materials and an imaginative approach to be able to address various applications. Commonly used textile materials — nylon, polyester and rayon — allow for this flexibility. Each has its own positive and negative attributes. Nylon provides mid-range stability and medium shrinking and is excellent at absorbing energy. Polyester offers better dimensional stability than nylon and low shrinking, but only an average level of energy absorption. Rayon is different still. Like polyester, it allows good stability, but it will deteriorate when wet, which shortens its long-term endurance.
M.H. Mahajanshetti, technical director, Global Rubber Industries Pvt. Ltd.: The tire industry is evolving rapidly to meet agricultural needs. Identifying the most effective tire for the application is important. Nylon and polyester belt plies are traditional. Some of the benefits of nylon are improved integrity at elevated temperatures, improved toughness, improved fatigue resistance, improved impact resistance — akin to armor, improved wear resistance, and more. Polyester/nylon tires provide the best performance for select applications. Here are a few considerations dealers should evaluate when choosing tires: traction, load carrying capacity, soil compaction, driver comfort, durability and value for money. Selecting the right tire for the application impacts fuel and vehicle efficiency, crop yield, soil or crop root damage, high carbon sequestration, vehicle downtime and maintenance, vibration and more.
Greg Gilland, vice president, global agriculture, Maxam Tire North America: The key difference between the two types of construction is how the radial tire uses the single radial casing as a spring mechanism to push the working belts onto the working surface. This ensures a uniform contact patch for the tire’s tread to deliver both the necessary traction and friction to carry the required load in any direction under power. In the case of bias-ply tires, the carcass is made up of multiple plies of material that function as a single unit like a balloon to push the tread onto the surface area. Under a working load, both tires work very differently as to how the tread area or footprint will function to deliver needed traction. e improved footprint and traction delivered by radial tires have accelerated the transformation of the specialty tire segment toward adopting radial tires.
David Graden, operational market manager, agriculture, Michelin North America Inc.: When choosing the best tire construction, it all comes down to application as nylon/polyester/steel-belt and all-steel casings have different features and benefits. When determining the right tire for an application, consider what the client will be doing with his machine. As a general rule, polyester is known for better ride characteristics, whereas nylon is known for increased durability. The need for one over the other can also be determined by how much or little Flexibility is needed for the tire to perform at its potential.
Ryan Lopes, national product manager, Yokohama Off-Highway Tires America Inc.: Though our selection of carcass ply material is often proprietary, the choice between polyester and nylon is typically a matter of balancing strength, adhesion, weight and cost within the demands of the application. All-steel construction offers the combination of durability, strong adhesion and excellent heat dissipation, which is why you’ll see it in premium ag tires designed for high-speed, high-strength applications. Another aspect of tire design lies in innovative uses of cap plies and belt edge strips, which allow us to tap into various materials to provide added functionality and enhance tire life.
