AG TIRE TALK KEY TAKEAWAYS
MICHELIN: When choosing best tire construction, it all comes down to application, as Nylon/Polyester/Steel Belt/All Steel Casings all have different features and benefits.
ALLIANCE: The steel belts help us ensure a flatter contact patch for better traction and more even wear, which is enhanced by the flexibility of the synthetic plies…steel belts also provide puncture protection.
BKT: All steel casings have a steel belt instead of a fabric belt running from bead to bead in a radial design….allowing for higher inflation pressures, more load carrying capacity, lower rolling resistance, higher speeds, and casing durability.
MAXAM: …we are seeing an evolution of ag tires toward nylon radial casing with steel belts or steel casing with steel belts.
Maxam Tire International
Greg W. Gilland: Business Development & Ag Segment Manager
The primary difference between radial tires and bias ply tires is in the tire carcass and the material construction of the tires.
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 or contact area for the tire tread to deliver both the necessary traction and friction to carry the required load in any direction under power.
The improved footprint and traction delivered by radial tires has accelerated the transformation of the agricultural segment towards fully adopting the radial tires as the primary type of tire construction on both new and older equipment.
By using different types of materials in the tire casing we can enhance or provide improved performance with the objective to deliver the optimal performance required ensuring improved traction, reduce soil compaction, and service life.
As agricultural machinery continues to grow in weight and engine horsepower, we are seeing an evolution of tires toward nylon radial casing with steel belts or steel casing with steel belts.
BKT USA, Inc.
Dave Paulk: Manager Field Technical Services
Although there are unique differences between nylon and polyester, both are important in ag tire manufacturing. It isn’t so much a matter of preference, but where do they work best in the manufacturing process and in the quality of tires produced.
Most nylon is made from unavoidable oil refinery by-products. It has low moisture absorbency, is resistant to damage from oil and many chemicals, is abrasion resistant, and has greater elasticity. Nylon is the second most used fabric behind cotton.
Polyester is used mainly in radial tires for rigidity and stability because of the low rate of shrinkage. This allows for consistent sizing between brands. It can also be used in high-speed bias tires for casing integrity as polyester does not grow in service like nylon. Polyester does not flat spot when cold like nylon does. Many of BKT’s radials such as the Agrimax series, Spargo, Teris, and Sirio incorporate polyester in their construction.
There are also differences in all-steel casing and steel-belted tires. Both have their advantages in different applications.
All Steel Casing
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 only one steel belt in the sidewall. Since steel doesn’t shrink or stretch, it allows for a consistent sized casing.
Steel Belt Casing
The steel belt helps the tire keep a flatter footprint and gives the tire carcass strength. They allow for higher inflation pressures, more load carrying capacity, lower rolling resistance, higher speeds, and casing durability. All steel casings have a higher ply turnup around the bead and are easier to repair sidewall cuts and punctures.
David Graden: Operational Market Manager – Agriculture
When choosing best tire construction, it all comes down to application, as Nylon/Polyester/Steel Belt/All Steel Casings all have different features and benefits.
When determining the right tire for your application, consider what you will be doing with your machine, then write a checklist of what you want to get out of the tire. Here are some examples:
- Will you be doing Severe Duty Skid Steer Work in Concrete Application with possible curb impact?
- Our All Steel Casing BibSteel is perfect for application.
- Do you need additional puncture resistance for Telehandler used for hay application in Rough Service Environment:
- Choose our XMCL Steel Belt to reduce punctures.
- Do you need a tire for your Trailing Implements that can handle Field Stones & Stubble?
- Our BFG Implement Control tire is a Steel Belted Radial with cut and chip resistant compounds.
Nylon vs Polyester
As a general rule polyester is known for better ride characteristics, whereas nylon is known for increased durability. The need for one of these over the other can also be determined by how much or little flexibility is needed for this tire to perform at it’s potential. At Michelin we build most of our VF Ultraflex tires with nylon, as it allows us to create a more flexible carcass while improving durability over our standard tires.
Yokohama Off-Highway Tires America
Ryan Lop, National Product Manager—Material Handling & Solid Tires
Though our selection of carcass ply material is often proprietary information (like compound formulations), the choice between polyester and nylon in light construction tire casings is typically a matter of balancing strength, adhesion, weight and cost with the demands of the application.
Construction tires are most often required to carry heavier loads, so strength is always important. The movement of different types of equipment places unique requirements on tires. For instance, a skid steer skids its tires to turn, which makes heat dissipation critical and wear properties of the compound essential. At the same time, a telehandler requires a tire with a strong, reinforced sidewall to minimize tire deflection to prevent the equipment from toppling over when its boom is extended. In both of those cases, we would engineer a carcass with a suitable number of plies and an appropriate material to optimize performance and maximize tire life.
Of course, all-steel construction offers the combination of durability, strong adhesion, and excellent heat dissipation, which is why you’ll see it in premium ag and construction tires designed for high-strength, high-speed applications.
Several of our most popular multiuse and light construction tires, such as the Alliance 550 and Alliance 551, for example, feature synthetic body plies overlaid with steel radial belts. The steel belts help us ensure a flatter contact patch for better traction and more even wear, which is enhanced by the flexibility of the synthetic plies. Of course, the steel belts also provide puncture protection.