The demand for large-volume farm tires — the kind found on today's large row-crop and 4-wd tractors — has never been higher. Tire makers like Firestone, Titan-Goodyear, Alliance, and Michelin all report record increases in sales of this farm tire, which is the industry's largest-size tire category today.

These tires appear oversized, but their larger carcass allows them to lift the weights of tractors and harvesters, which are growing in size. Manny Cicero, president of Alliance Tire USA, sums up the trend in three words: bigger, stronger, faster.

“As agriculture continues to consolidate and commercial farms continue to grow in acres, tires are being asked to carry bigger loads and higher vehicle weights for longer distances at increasing road speeds,” Cicero says. “These new demands call for a tire that is built large enough to carry the load but strong enough to distribute the ground pressure and withstand road speeds of 30 mph.”

New breed of tire

Today's large-volume tires are the largest diameter tractor tires available, normally with a rolling circumference index (RCI) of 47 or 48, which equates to a tire height of 77 or 81 in., respectively. The extra inches allow room for more air without increasing pressure inside the tire. Lower air pressures result in a bigger tire footprint that distributes the load to reduce ground pressure, thereby reducing soil compaction.

The Tire and Rim Association, the governing body for U.S. tire makers, calls for an R1-W tread depth on RCI 47 and 48 tire groups. The W is a “wet” tread designation that provides for a deeper tread than that on standard R1 tires to allow for more traction in wet field conditions.

“These size tires have been out for five to seven years now, so we are just now hitting the first full replacement cycle,” reports Tom Rodgers, marketing manager with Firestone brand ag tires. “That larger tire seems to be lasting longer and wearing longer under normal conditions. So what we are seeing is, first, a lineup for these tires for replacements and, second, a continued demand for them by vehicle manufacturers.”

In addition, the growth in high-horsepower tractors is creating more of a demand for these large-volume tires.

All of these factors have resulted in a tight supply and high prices. “We haven't had the capacity to fill the coffers at the dealer level,” Rogers says. He expects supplies will continue to be tight throughout the first half of this year. He says the combination of softer raw material prices and strong demand has at least allowed ag tire pricing to stabilize.

IF technology

Growers who want even lower ground pressures can upgrade to a radial with “increased flexion,” or IF technology. IF denotes tires built to provide 20% more flex in the sidewalls, which allows the owner to reduce air pressures without compromising the tire. VF, another flexion designation, refers to tire technology that provides an additional 20% lower inflation pressures than in IF tires.

The Tire and Rim Association created the new IF and VF categories for the new generation of high-flex, low-pressure tires. To date, Michelin is the only tire company that makes an IF or VF tire for the U.S. farm market. Firestone announced last year that it had plans to make an IF or VF tire available to the farm market. Titan also says it is researching the technology.

Michelin reports that it sees growing demand for its IF tire called the Axiobib with ultra-flex technology that the company launched in 2006. Michelin first made the IF tires available on the Challenger MT series of tractors. Michelin also offers a VF category tire called Xeobib.

“While we have the R1-W [Agribib] tire, our mission is to develop technologies that go beyond it,” says Michael Burroughes, director of marketing for Michelin North America Agricultural Tires.

Burroughes says demand for the Axiobib is seen mostly at the factory level because it requires a larger wheel rim than is required on R1-W tires. However, he says, some farmers are using it as a replacement tire and are willing to foot the bill for the wider rims because of the benefits gained from the tire's larger footprint.

Last year Michelin introduced a tire that lets growers who are using standard-size tires upgrade to a lower inflation radial without changing rims. This new tire, called the Multibib, provides a 25% larger footprint than the standard-size Michelin Agribib.

What's ahead?

All the tire companies expect the demand for large-volume tires to continue to grow as tractors and combines increase in horsepower, size, and weight.

Also expect more companies to offer IF tires. Michelin plans to make the IF tire in more sizes and more categories so that farmers with all types of equipment can get the same benefits.

Jeff Vasichek, vice president of sales and marketing, Titan, says there will be even more choices as tires get even more application-specific. “One tire being developed is the low-sidewall tire that offers benefits for better ride and traction,” he says. “In general, the trend will be taller, larger tires and it will be narrow for row-crop and high-load for sprayers. They will be wider for high-horsepower tractors. We're also looking at tires for speeds above 40 mph.”

Alliance, which specializes in niche applications including agriculture and forestry, agrees. The company offers a number of options in farm tires and expects to double its capacity this year with the opening of a new factory. Alliance's Cicero also says the multipurpose farm tire won't go away. He expects this category to grow as much as the specialty tire market.

Tracked tractors, which hit the market in the '90s as an alternative to tires, will continue to have a place, but perhaps not near the market penetration levels that were forecast years ago, according to Titan's Vasichek. “When tracks were introduced, some manufacturers predicted they would be 40% of the market. That never materialized,” he says.

He thinks tracks will be suited for specific applications, mainly where soils tend to be wet. So there's a need for tracks, but the high number of moving parts in tracks make them expensive to maintain.

TIRE-BUYING TIPS

TIRE MANUFACTURERS see continued demand for large-volume radial tires, and they report supplies will continue to be tight in 2009. Tight supplies drove tire prices to record highs last year. But this year prices are expected to stabilize due to a slight drop in the cost of raw materials like oil, rubber, and steel.

Because these tires are to be in short supply, tire manufacturers recommend that growers contact their tire dealer as soon as possible to ensure they get the size they need.

Another piece of advice is to work with a dealer equipped to handle these larger tires. “These tires are larger than anything we've seen in the ag business,” Firestone's Tom Rodgers says. So it is important to work with a dealer who is readily available when needed and who has the equipment and manpower to install this large tire.