Understanding VF Farm Tires
A quick Google search will pop up numerous articles—many published by us—touting the benefits of VF tires, and testimonials from customers who’ve gotten great results using them. Most of the columns and blogs will tell you why you should put VF tires onto your farm machinery, but very few actually explain what VF farm tires are, and why you should consider investing in them.
Photo of Alliance AgriFlex+ 354 tires on a John Deere 7720 tractor from Degenhardt Tire
What is a VF Farm Tire?
The “VF” in VF tires stands for “very-high flexion.” While VF isn’t the catchiest of monikers, it aptly explains the nature of a VF tire, which is essentially that they're very, very bendy in the sidewall. VF tires are superior to standard radials in that they have extra-strong casings and specially designed sidewalls which allow for greater flexion, and they direct that flexion to the portion of the sidewall away from the bead and nearer to the tread, producing the VF tire’s telltale sidewall bulge.
Designing VF Tires for Deflection
The bulge you see on the sidewall of properly inflated VF tires is the result of deflection—deflection is also the major challenge facing engineers when building VF tires. Deflection, or the difference in the radius of a loaded vs. unloaded tire, occurs in all tires. The greater a tire’s deflection, the more a tire’s sidewall deforms and its footprint lengthens when under load. Because VF tires are engineered to carry heavy loads and operate at low inflation pressures, VF tires are built to have higher deflection and withstand more severe shape shifting than traditional radial tires.
To withstand the forces deflection places on a VF tire’s casing and tread, Alliance incorporates steel belts and special rubber compounds into all of our AgriFlex VF tires. Steel belts are stronger and thinner than fabric belts and better able to handle the stress and heat caused by deflection, and our specially formulated rubber compounds are engineered to stand up to the constant stretching and compression that occurs on the flexing sidewall of a VF tire.
Why We Need VF Tires: The Evolution of Tire Technology
The more we learn about soil compaction, the more it becomes apparent that while today’s larger and more powerful farm equipment can increase the efficiency of chores like planting and harvest, it also can negatively affect the productivity of soil if not properly managed. VF tires provide farmers an easy way to reduce the impact of their equipment on their fields.
One of the greatest advantages of VF tires is their ability to operate at lower inflation pressures than other comparable tires, consequently reducing soil compaction. VF tires can carry the same load as a standard radial tire at 40% less inflation pressure. In general, the amount of pressure a tire exerts on the ground is equal to the amount of pressure the tire is operating at. Consider the positive effect a VF tire can have on your field by simply allowing you to change the pressure in your tires from 50 psi to 30 psi—especially when using 100,000-pound pieces of equipment!
Furthermore, a recent soil compaction study from Penn State’s College of Agricultural Sciences found that the contact pressure exerted on the ground by a standard farm tire is uneven due to sidewall stiffness—this is most pronounced when operating at high inflation pressures, which stress the ground underneath the center of the tire if it’s overinflated and along the edges of the tire if it’s inflated properly. Tires with extremely flexible sidewalls, such as those with VF technology, distribute the load more evenly across the entirety of the tire’s contact patch.
Calculating a VF Tire’s Footprint
When manufacturers display the specifications for a tire’s footprint, they always use the numbers taken when the tire is under maximum pressure and load because they’re the most impressive. Luckily, calculating the “real-world” footprint area of a VF tire isn’t rocket science: simply divide the load placed on a tire in pounds by the psi of a tire to arrive at the footprint area in square inches.
Alliance Whole Farm Concept
Tractors and combines are just two of many machines that compact the soil. Other equipment, from planters to disks and sprayers, also cause compaction. Alliance is focused on producing AgriFlex+ VF tires for the whole farm. Because it’s not just tractors causing compaction in the fields, we’ve been rapidly developing VF implement tires covering the spectrum of farm machinery and helping farmers minimize compaction in all seasons, from spring fieldwork through fall harvest.
Alliance AgriFlex+ VF Tires
No small feat of engineering, getting a tire to flex under heavy loads and high speeds, along with getting it to flex in the sidewall shoulder rather than near the bead, is no less impressive than the auto-steer in your tractor. It’s also a feat Alliance has mastered. We’re so confident in the superior quality of our AgriFlex tires, we back them with an outstanding 10-year warranty—which makes choosing Alliance even easier.