Farmers today have more options than ever when it comes time to select ag tires. One of the most common ways to differentiate the multitude of farm tires on the market is to divide them by their construction—bias ply or radial. Both bias and radial tires have their advantages, but radials stand apart as there are no real drawbacks to their use in farming applications. Keep reading to learn more about the features and benefits of both types of tires.
Bias-ply tires are nearly as old as pneumatic (air-filled) tires themselves—they’ve been a common sight on farms for almost a century—and still present a viable option for many machines. Bias-ply tires are made by lapping multiple plies of rubber-coated textile diagonally over each other—also called “on the bias”—to create a single working unit. The construction of bias tires allows the sidewall and tread to work together as a single unit.
Bias construction creates a rugged, durable tire with stiff strong sidewalls, which helps them prevent threats like stumps and rocks from damaging them. Bias construction also offers excellent stability and makes them a great choice for machines that frequently work on hillsides.
Bias tires are stiff, consequently, bumps in the field are transferred to the machine and operator—this can lead to more wear and tear on equipment along with delivering poor ride quality. Bias-ply tires also transfer movement across the entire tire—when its sidewall flexes, so does its tread—which produces a smaller, less-even footprint and ultimately can increase wheel slip, decrease traction, and lead to yield-lowering compaction.
Radial tires continue to claim more and more of the ag tire market. One reason for the rising adoption of radial tires is that they’re better able to meet challenges presented by the growing size and power of today’s farm equipment. The main differentiator between radials and bias-ply tires is that radials are made in two parts—which work independently of one another—with body plies that run perpendicular to the bead and an undertread area that’s wrapped around the tire’s circumference by radial belts of fabric or steel. Radial construction results in a tire with a broad, flat footprint with increased puncture resistance in the tread area. A radial tire is able to produce a footprint that is 15% to 25% larger than a comparable bias tire.
The two-part construction of radial tires allows them to flex in their sidewalls but not transfer the movement to the tread. This results in better traction, lower fuel consumption, and reduced soil compaction and ultimately helps to improve farm efficiency and productivity. Other benefits of radial tires include a more comfortable ride, better heat (the number one enemy of tires) dissipation, and longer service life.
The biggest knock against radial farm tires is that they typically have a higher up-front cost than bias tires. However, radials can have a 30% longer service life and have a lower total cost of ownership than bias tires.
While radial tires are becoming more prevalent on the farm, they’re not exactly a modern advancement. Radials were invented in the 1940s, gained popularity on automobiles in the 1970s, and rendered bias tires on automobiles obsolete by the early 1980s. That said, the performance of radial tires continues to improve and meet the challenges of modern machinery thanks to innovations like IF/VF technology.
IF/VF tires are radials with a sidewall engineered to allow more flex—IF stands for “increased flexion” and VF stands for “very high flexion.” IF/VF tires are able to carry higher loads and operate at lower inflation pressures than traditional radial tires.
The ability of IF/VF tires to operate at low pressures allows them to create larger footprints, which helps to improve traction, reduce slippage, and lessen soil compaction.
If you’re going to invest in radial or IF/VF tires, make sure to also buy a good tire gauge and get in the habit of regularly checking tire pressure. To truly take advantage of the benefits provided by traditional radials and IF/VF tires, it’s important to ensure they’re properly inflated. A survey conducted in Oklahoma found that only 45% of the tractor tires were within the recommended tire inflation ranges.
If you’re still unsure whether a bias, radial, or IF/VF tire is right for you, contact your local Yokohama Off-Highway Tires America (YOHTA) dealer or rep to learn more about our expansive range of ag tires. YOHTA has a variety of tire options for every piece of equipment on the farm—all of which are engineered to solve the real-world issues facing farmers.