Tires Versus Tracks

TIRES VERSUS TRACKS

BY J.R. WILSON

Fifty years ago, tractors rode on large tires and tracks were rarely seen outside of construction sites.

In recent years, however, tracks have gained a foothold in the agricultural market, albeit one that seems to have reached its peak.

“Tracks have been around since the late 1980s in agriculture, but it never really stuck because they were expensive and just not practical. But they perform better and are much more economical now,” said James Crouch, national agriculture product manager for Alliance Tire Group. “The equipment makers were kind of forced into making tracks.

“The quad track is everyone’s reference when you think about tracks in agriculture. It was introduced and popularized when commodity prices were high, around 2008 to 2011, when farmers had a lot of money and were willing to try new things. Tracks were sold as the ultimate solution, so farmers saw that almost $90,000 update cost as a kind of insurance.”

When the quad track really got popular, the horsepower range for big tractors was from 380 to 500, and now is up to 600-plus, he explained: “When you look at putting that much power to the ground, tracks do very well. There also is a gap in the understanding of tires, which are taken for granted. More than 75 percent of tractor tires are overinflated, which shrinks the footprint, and slip increases. So there is an education gap between proper tire maintenance and tracks.”

While the commodities market, especially for corn, has dropped, some pockets of demand for tracks remain strong, while others may begin trending towards tires, according to Scott Sloan, global agricultural product manager for Titan International, which produces the Goodyear line of farm tires – but no tracks.

“Case is running about 60 percent quad tracks and John Deere has maybe 35 percent going out as tracks,” he acknowledged. “It will be an ongoing battle for track sales, with cost and maintenance being major factors in some customers moving to tires.

“Some of the larger operations will try to stay on tracks. But with up to a $110,000 difference, the guys who are on the fence or really trying to reduce costs will turn to tires. That’s where we have an opportunity, as we develop flotation tire options designed to perform equally as well as tracks, but at a much lower cost.”

“Tracks have their place, tires have their place; it depends on what the end user is trying to achieve.”

Michelin North America, a long-established name in tires, recently added track manufacturer Camso, based in Quebec, to its business line.

“Now that we have Camso, that makes us a track company,” said Michelin agriculture marketing manager David Graden. “My stanceis very much the same: tracks have their place, tires have their place; it depends on what the end user is trying to achieve.

“Where there has been rapid growth in tracks, that will level off and there will be a better balancing of the two. There will be a continuing increase in tracks in the South and Southwest, but tracks will level off in the Midwest as CTIS [Central Tire Inflation System] becomes better known and used.”

Covering its bases, Michelin also recently acquired two CTIS companies – German-based PTG and Téléflow in France – both leaders in systems that enable fully automated pressure adjustment to vehicles while on the move.

The key reason for the regional market difference in tire versus track sales is soil composition – clay and sand in the South, sand in the Southwest, both of which are far less vulnerable to compaction than the rich dark soil that blankets most of the Midwest.

In a list of factors farmers must consider when weighing tires versus tracks, recent studies (largely done by or for tire manufacturers) have given the edge to tires in most categories. Graden explained the most common results: INITIAL COST – “Tires are less expensive at initial purchase, even with the addition of a CTIS. On a quad track – and it depends on the machine – tires on a four-wheel can cost $7,000 to $8,000 per tire and there are eight of them. The upcharge for tracks is around $70,000, [roughly twice the price of tires].”

A Case IH Steiger 580 equipped with the world’s largest farm tires (Goodyear ® OPTITRAC LSW1400/30R46) went head to head against the Case IH Steiger 580 Quadtrac machine. Results from the test showed the wheeled machine had greater fuel efficiency and improved ride quality.

MAINTENANCE AND REPLACEMENT – “Tires are less expensive to maintain over the course of an average 4,000 hours; track replacement parts are more expensive and the time it takes to maintain all the moving components in tracks is more.”

FUEL COSTS – “It depends on the machine, but in studies we have done on a quad track versus four-wheel drive, fuel is less expensive using pneumatic tires because it takes more horsepower to move all the moving parts and additional weight of a tracked machine.”

TRACTION – “Traction goes to tracks. The track itself doesn’t spin like a tire, but lays down a road for the components inside the track to roll over.”

POWER – “With a quad track, it takes up to 50 percent more power to move the track than a pneumatic wheel, so if you stick with power only and not combine it with tracking, it goes to tires.”

WEIGHT – “Weight also goes to the tires. You have a significant amount of additional weight for tracks.”

ROAD SPEED/EFFICIENCY – “That goes to tires. Tracks, depending on their width, are limited to a certain speed before they begin to overheat.”

SOIL COMPACTION – “It tends to depend on the part of the country – and can be a point of heartburn for those in the Midwest who purchased tracks. Compaction is a big issue in less sandy soil, such as the Midwest, and tires have a much lower downward pressure. Tracks are traditionally pitched on contact area, which has little to do with compaction. When you get into clay and sand, soil compaction is not an issue because they don’t compact, so tracks really excel in those areas.” Tires also win when it comes to ride and comfort. “A track machine is like riding in a tank,” Sloan added, predicting little is likely to change in the comparison despite improvements to track technology in the years to come. “But tires can have their ride quality issues too. Power hop and road lope can inhibit field and on-the-road performance. Those are issues that we’ve worked to solve with Low Sidewall (LSW) technology.”

Left: A comparison chart of tires and tracks shows various applications for different attributes.

Sloan also points out that when it comes to tires versus tracks, people often confuse the terms flotation and compaction. Both are important, but are separate considerations when selecting tires or tracks.

“There’s a difference between compaction and flotation. Flotation is what gets you through mud; compaction involves the footprint. Tracked machines are significantly heavier than wheeled machines, but we did a test where we added ballast to make them equivalent and found the ground bearing pressure beneath the bogies [the wheels inside the track] was significantly higher than under a tire. A tire equalizes the pressure across the footprint, which is reaching a significant size, although still smaller than a track. That equates to lower soil compaction, and potentially greater yields by going with a flotation LSW tire.”

Modern tractors are bigger, heavier, more powerful, more costly, and more comfortable. Tire manufacturers acknowledge putting tracks on a large quad machine makes for an impressive sight that may influence some buyers. That trend toward increasingly larger machines also can lead to a belief they must be equipped, if not with tracks, than with the largest available tires.

Michelin warns farmers they should choose tires based on performance – and bigger is not always better, possibly reducing equipment efficiency. Instead, the company recommends farmers avoid “over-tiring.”

A track footprint is larger than a tire footprint, but the ground pressure under the bogie wheels is higher (as indicated by the graph spikes as downward force) than from pneumatic tires.

Today’s tractors also are far more advanced electronically, with driver seats that would make Capt. Kirk green with envy. Those electronics include CTIS, which monitors tire pressure and allows the driver to inflate or deflate tires on the fly based on surface conditions, load, and other factors.

CTIS is an add-on and, based on the number of tires, can cost from $7,000 to $25,000 per tractor, which includes an air compressor, hoses, electronics, and labor. Auto inflation/deflation is part of CTIS, and Graden predicts several new technologies now being developed eventually will enable “smart tires” that can measure soil moisture and density, then change tire pressure accordingly without any action by the farmer.

“I don’t know that anyone is within five years of that, but I think that is the long-term future of CTIS,” he said.

Currently, the driver can press a button in the tractor cab to change from field to road and back again. But while a fully autonomous, sensor-based system will be a marked improvement, the tire makers are committed to educating their customers today about the importance of tire pressure – and its competitive impact versus tracks.

This CASE Quadtrac is using tracks in a hay field.

“A common tire is 18.4 inches wide and that’s pretty much the most you get, but you can make it longer with lower pressure, putting more tire on the ground. That’s a step that was missed by the OEMs [original equipment manufacturers] as a solution to putting power to the ground,” Crouch explained. “Long term, tracks have a market they will control. As fields get wetter, tracks don’t respond like tires when it comes to the slip increase; tracks stay about the same rate.

“The future is low-pressure tires and proper inflation; the missing piece is the ability of the tractor to know what the tire pressure is and should be. Static loaded radius – distance from center of the tire to the ground when inflated – means the tire pressure is irrelevant. The technology is almost there to do that automatically, in the next 15 years, in a way the farmer won’t even realize what’s happening.”