Keep ‘Em Rolling

March 1, 2009

You can’t make money moving dirt if you can’t move your machine. That’s why it pays to choose tires and tracks that not only fit your grading and excavation equipment but also match your job-site conditions.

Here are some ideas and options that may help prevent you from getting bogged down by rocky terrain, muddy ground, rough roads, and other obstacles in your path to more productivity and profits.

New Life for Worn Tires
Looking at thin tread on a well-traveled tire, some grading and excavating contractors see a worn-out tire that needs to be discarded. Profit-minded contractors, on the other hand, look at that same tire and see an asset—the tire casing—that can be recycled to save money.

That’s the idea behind retreading. “When you buy a premium-quality new tire, you’re paying not only for the performance of that tire but also for the life that’s left in the casing of that tire once the original tread is worn. Retreading can capture that remaining value,” says Chris Hoffman, manager of truck and bus radial and retread product marketing for Bridgestone Bandag Tire Solutions. The company’s franchised retreading services can be used to add new life to tires for dump trucks as well as such other construction equipment as motor graders, articulated dump trucks, wheel loaders and skid-steer loaders.

Owners of both large and small equipment fleets can benefit from retreading tires, he notes. “You can retread a tire casing for about 40% to 60% of the cost of buying a new tire,” Hoffman says. “A retread doesn’t last as long as the tread on a new tire. But, because of the lower cost of the retread, it offers a lower cost per mile or hour of operation.”

He reports that a tire for a truck, articulated dump truck, or wheel-loader can be retreaded several times, depending on road and job-site conditions, before it is no longer usable.

The environment can also benefit from retreading. As Hoffman points out, a retread can be produced using 30% of the energy required to make a new tire. For example, it takes 22 gallons of oil to manufacture one new truck tire. Most of the oil is found in the casing, which is reused in the retreading process. As a result, it takes only 7 gallons of oil to produce a retread.

One challenge facing the tire retreading industry is a misperception by critics who blame retreads for the large chunks of rubber sometimes strewn along highways and shoulders. Often, these rubber scraps include tread and wires, leading some people to assume they were left on the road by a retread failure. However, the rubber added to tire casings by retread companies contains no wire. The presence of wire in those scraps indicates failure of a casing, not of a retread, reports the Tire Retread Information Bureau (TRIB). In fact, the bureau notes, the scrap rubber on the road results from a tire—whether a new one, one that has never been retreaded, or a retread—destroyed by inadequate tire pressure and heat buildup of the tire. “Adjustment percentages of retreaded tires are about the same as with new tires,” according to the bureau.

The Rebuilding Process
Retreading of truck tires dates back to the early days of the trucking industry. The practice got a boost about 40 years ago with the growing popularity of steel-belted radial truck tires. The volume of retreading continues to grow, Hoffman notes.

“The recent shortage of tires caused more people to take another look at retreading and the quality and cost-saving benefits,” he says.

More information on retreading is available at TRIB’s Web site: www.retread.org.

The Bandag retread process, which was developed in Germany, was brought to the United States in the 1940s by Roy Carver, who started the first North American dealer franchise, based in Muscatine, IA.

Today, in North America, the Bandag retread process is offered by more than 1,600 sales and service franchisees. This process begins with a 14-point visual, hands-on inspection from bead to bead, inside and out, to find and mark all visible defects.

High-voltage electrical current is then run across the interior surface of the tire to find and identify the location of all “through-the-tire” penetrations in the crown and shoulder areas. In the final phase of this initial inspection, the casing is subjected to a vacuum while lasers measure any surface defects, such as expanding pockets of air that might affect performance of the casing.

Next the casing is mounted onto a rotating hub and then inflated and buffed to remove the worn tread surface. Damaged materials are removed and repaired as needed to return the casing to a useful life. Then, the uncured bonding layer of rubber is extruded onto the prepared casing surface and a machine called a ‘builder’ applies new tread.

The newly built, uncured tires are placed in an elastic envelope that creates an airtight seal around the tire before heat and pressure are applied. This causes the bonding layer in the built tire to cure, permanently adhering the new tread to the casing.

Finally, the tire is given another visual, hands-on inspection to ensure that the tire has been properly retreaded and meets quality specifications.

The Bandag process includes a variety of tread designs and synthetic rubber formulations to meet such specific performance requirements of the tire as traction and resistance to cuts and chips. The choices include the BDM product, which features a unique tread compound for on- and off-road truck applications. “It’s designed for trucks hauling aggregate and offers very good traction around the job site and high wear-resistance for highway travel,” Hoffman says. “It runs as well as a new tire.”

More information on retreading is can be found online at www.bandag.com.

Improved Tire Supply
The shortage of new off-the-road (OTR) tires for construction equipment that many grading and excavating contractors have faced in the past few years has started to ease. However, in some cases, demand still exceeds supply.

This reflects the cyclical nature of the construction tire market over the past 20 years or so. In 2003, a surging demand around the world outpaced the industry’s manufacturing capacity. Tire makers have been struggling to catch up since then. However, the supply situation continues to improve as home construction activity has dropped and as Chinese and European tire makers send more products to the US.

“There’s still a shortage of off-the-road products in some sizes,” says Gary Nash. He’s director of OTR sales for Yokohama Tire Corp. The company manufactures pneumatic OTR tires for a wide range of construction equipment, including scrapers, articulated dump trucks, motor graders, front-end loaders, and wheel dozers.

“There’s a big backorder for large and extra-large tires,” Nash says. “And it looks like this will go on for several years, maybe as long as five to 10 years. The shortage of some sizes of small and medium tires continues. There seems to be a pretty good supply of radial products in the smaller sizes. And there seems to be a decent supply of the small- and medium-bias tires, with the exception of selected sizes for niche markets.”

Making a Tire
While the details of a particular type of pneumatic OTR tire depend on the specific machine and job applications, all tires—whether bias or radial design—feature common components:

    • Casing, which provides a semi-rigid frame for the compressed air inside to support the machine and which also absorbs some of the shocks

and jolts

  • Treads, which protect the body of the tire from cuts and wear and which feature a specific pattern affecting traction and other performance characteristics
  • Sidewalls, made of flexible, crack-resistant rubber to protect the casing from damage
  • Beads, reinforced by wires, which secure the tire to the wheel rim

As examples of how sophisticated the engineering can be in making the most of these basic components for extreme applications, Yokohama makes the 4000-57, which is designed for a specific operation. A complete job-condition report is necessary to place this tire in operation. A job-condition report includes the type of terrain in which the tire is being used, as well as the speed, the distance of the haul, and the total load requirements. After this has been determined, Yokohama then sends the data to its engineering department. Then the tire is specially designed and manufactured to meet the criteria.

The 4000-57, which stands 12-feet tall and weighs nearly 4 tons, is designed for industrial-grade, 240-ton haul trucks used in mining operations as well as in steel mills and many other specific applications requiring special design requirements.

The company also makes tires for a system that moves three-story oilrigs around at Prudhoe Bay, AK. Equipped with eight of these tires, this system transports 2.2 million pounds of equipment as far as 40 miles from one site to another in temperatures colder than –50°F. One haul trip required 12 hours to move an oilrig 10 miles.

In designing OTR tires, engineers use various types and amounts of natural and synthetic rubber compounds and tread patterns to produce the desired traction, load capabilities, and resistance to cuts, oil, and heat.

“The combination of ingredients that go into compounding the natural and synthetic rubber is a big key to performance,” explains Nelson Richards, national sales manager for Yokohama. “We custom-compound tires to meet specific customer needs. For example, we can design a cut-resistant compound for tires used in rocky conditions, where tires are more prone to cuts. Or, if the tire application requires more traction, we can formulate a softer rubber for that particular use.”

The compounding ingredients may include any of more than a dozen types of carbon black and others, such as oil and kaolin clay.

In all, he reports, his company’s lineup of OTR tires features more than 250 individual tire models, reflecting variations in sizes, materials, and tread patterns.

Bias tires are made from a number of rubber-coated layers of fabric, called plies, which run at an angle from one bead to the other. They are designed for carrying heavy loads short distances, Richards notes. Radial tires feature steel plies placed at angles between the casing ply that runs at a 90-degree angle to the tire bead and the tread rubber. Running cooler than bias tires, radials are better suited for carrying heavier loads long distances.

Tire Differences
Another factor to consider in selecting OTR tires is the ability of the tires to provide traction and flotation on sand, mud, and rock. These factors depend on the pattern of the tread. A rock pattern is designed to prevent cuts by rocks. Its large ground-contact area provides excellent wear characteristics. The traction pattern features lugs running at an angle from the sidewall to the center of the tire tread. The block pattern, with its wide tread width and rounded shoulders, uses a large ground-contact area to lower ground pressure. Also called an alligator or button pattern, it is well suited for use on soft, muddy ground. The rib pattern, used mainly on free-rolling wheels, has grooves running parallel to the direction of travel, providing a high degree of directional stability.

Tread thickness of OTR tires can be classified as regular, deep (1.5 times thicker than regular) and extra deep (2.5 times thicker than regular tread). The thicker the tread, the greater the resistance to cuts and wear.

However, thicker treads also produce and hold more heat. That’s why Richards recommends evaluating work conditions for thick-tread tires thoroughly to prevent heat separation and other heat-related damage. Also, take into account the larger overall diameter of tires with thicker treads when replacing regular-tread tires with deep or extra-deep-tread tires.

Another consideration in choosing an OTR tire, Richards notes, is the quality of the casing. The stronger the casing, the more times it can be retreaded. In addition to the type of compounds used to build the casing, the way in which the materials are used to build the tire also affect the strength of the casing. For example, tensile strength of the tire bead depends not only on the wires used to construct the bead, but also on how these wires are arranged in making the bead. The more uniform this arrangement, or wrap, the stronger the bead.

When buying tires, Richards recommends working with a dealer to make sure you select the best tire for your needs. “Buying tires for construction equipment isn’t like choosing tires for your car or pickup,” he says. “The misapplication of an OTR tire is much less forgiving in terms of performance. OTR tires are engineered to be rugged and strong, to do a particular job for a particular type of construction project. Equipping your loader, motor grader, or other machine with the wrong type or size of tire can shorten expected tire life significantly. Most dealers have the technical knowledge and experience to make sure you get the most cost-effective tire for your needs.”

More information on Yokohama’s line of OTR tires, along with tips for selecting, using, and maintaining tires is available at www.yokohamatire.com.

Replaceable Lugs for Compact Track-Loaders
Rather than buying a new track when the drive lugs on the rubber tracks of his Caterpillar MTL compact machine broke, excavating contractor Larry Bair invented a bolt-on replacement lug. Bair, who owns Bair Excavating Inc., a third-generation, family-owned excavating and site utility company in the Kansas City area, founded Bair Products Inc. to produce these lugs. Called Larry Lugs, they are made of a composite material.

“They replace broken, worn-out, torn-off, and delaminated rubber drive lugs on Caterpillar MTL and ASV loader tracks,” says Tonya Bair, the company’s operations manager.

“You can install them in the field in about 10 minutes without removing the track from the machine. If the track becomes unusable, you can remove the Larry Lugs and mount them on another track,” Bair says.

Larry Lugs are designed to fit Caterpillar 247, 257, 267, 277, and 287 MTL loaders and ASV RC 30, 50, 60, 85, 100, and SC50 compact track loaders or similar machines

Gregg Corcoran, maintenance supervisor for Milton C. Beebe & Sons Inc., a site-work contractor based in Storrs, CT, has installed more than 40 of the Larry Lugs over the past year or so on the company’s Caterpillar 257 MTL loader.

“Over time, the original lugs on the tracks start to wear out,” he explains. “Once three or four lugs in a row are gone, the machine won’t move, even though there’s still good life left in the tracks. Instead of spending more than $2,000 to replace the track, we replace the damaged lugs with the Larry Lugs.”

Corcoran uses a 4-inch carbide wheel (also bought from Bair Products) on a hand-held angle grinder to grind the old lug down to a flat surface. It takes about five minutes to do that, depending on how much of the original lug is left, he reports. Using the drill template that comes with the Larry Lugs, he then drills two boltholes through the track and bolts the new lugs in place.

“We’re very happy with the Larry Lugs,” Corcoran says. “They’ve worked out very well for us and haven’t affected track performance. Once the tracks are worn out, we’ll remove these lugs and use them again.”

More information about Larry Lugs as well as idler wheels, bogie wheels, and other rubber track parts is available at www.bairproductsinc.com.

Tracks for Tires
Steel tracks that fit over the tires can keep skid-steer loaders making money in such soft conditions as sand or mud by increasing flotation, or on rocky ground by protecting the tires from cuts and abrasions. The added weight of steel tracks also boosts lifting ability somewhat compared with that of a skid-steer loader without tracks.

Grouser Products offers three styles of over-the-tire steel tracks. The Bar Track features an open-bar design for maximum traction and flotation and induction-hardened crossbars and traction bars for durability, reports Gary Luther, the company’s sales manager. It’s also the only steel track recommended by skid-steer manufacturers, he adds. A patented open side plate and run-loose design helps the tracks shed mud, sticks, rocks, and other debris, reducing stress on the track and the machine. The Bar Track can be installed in less than 30 minutes and removed in about 10 minutes, Luther notes.

Based on the design of the Bar Track and aimed at contractors who prefer a solid track for hard, aggressive work, the Hard Track has replaceable metal shoes or inserts. “You can replace the shoes using an air wrench to remove the bolts from the old insert and a torque wrench to install the replacement shoe,” Luther says. “You can replace all the shoes on a track in about an hour.”

Similar in concept to the Hard Track, the Grouser Soft Track features replaceable, nonmarking urethane shoes for working on concrete, asphalt, and other sensitive surfaces. They are interchangeable with the steel shoes of the Hard Track. “The urethane inserts are more durable than rubber,” Luther says. “They can withstand cuts and abuse and keep on running.”

General contractor Mike Staber, owner of American Enterprises in West Fargo, ND, mounts Grouser Bar Tracks on his New Holland L190 skid-steer loader when clearing deadfall from river banks in the winter. Equipped with optional ice picks, the tracks give traction to work on frozen rivers and scamper up and down snow-covered banks.

This work, which lasts several months each winter, helps prevent spring logjams composed of trees swept into the rivers when melting ice and snow causes the water to rise. After cutting up the trees, Staber uses the skid-steer loader to place the logs in large burn bins.

The steel tracks replace the tire chains that he once used. “The chains didn’t work very well,” he recalls. “They didn’t keep the tires from spinning, and they often broke. If I was in deep snow and didn’t clear the area in front of the skid-steer loader, I’d get stuck.”

The steel tracks have eliminated those problems, Staber reports. The tracks, minus the ice picks, also come in handy for keeping his skid-steer loader working in muddy and slippery conditions at times of the year when he would otherwise be spinning his wheels.

It takes him about 15 minutes to install each track. When not needed, he rolls the tracks into a ball and stores them in his shop building.

Staber has been impressed by the durability of the rugged tracks. “They’ve never broken,” he says.

A Track Just for Compact Loaders
The latest design in replacement rubber tracks for compact track loaders from McLaren Industries represents an entirely new class of high-performance rubber tracks, reports George Zafirov, the company’s marketing manager.

Unlike most types of rubber tracks for compact equipment, this new line, called NextGen TDF rubber tracks, has been engineered specifically for use on compact track loaders, he notes.

“Typically, rubber tracks used on skid-steer loaders and compact track loaders, are made with the same technology used to make tracks for compact excavators,” Zafirov says. “However, a compact track loader is a totally different machine that imposes much higher stresses on the tracks than an excavator. The NextGen technology balances strength and flexibility throughout the rubber track to handle the workload and abuse of the most powerful compact track loaders.”

Special rubber compounds extend service life of the track by as much as 50% compared with conventional rubber tracks, he says. The rubber also helps contain minor cuts and cracks that can otherwise expand to several times their original size, reducing track life.

The track’s proprietary SpoolRite Belting continuous belt system offers much more tensile strength than typical jointless cable tracks, he adds. “Rather than winding a series of cables, which may differ slightly in length, around the track, the cables in the NexGen tracks are uniform in length and placed very precisely to form an inner steel belt that can handle much higher stress forces without breaking,” Zafirov says.

A fiber mesh embedded in the rubber provides better shielding and protection for the cables than a conventional track. In addition, the multiple-lug, double-offset tread pattern protects the track body better, reducing wear on the undercarriage of the track loader and providing a smoother ride.

More information is available at www.mclarenindustries.com.

Removable Undercarriage for Skid-Steers
With the VTS-Versatile Track System from Loegering Manufacturing Inc., you can use your skid-steer loader as is with tires for quick and agile maneuvering. Or, you can remove the wheels and bolt the VTS onto the hubs and use this same machine as a compact track loader with a suspended rubber track undercarriage for added traction or flotation to fit your needs.

“You can install the VTS in less than an hour without modifying your skid-steer loader,” says Loegering’s Chris Kaspari. “It will fit just about any make or model of these machines.”

Typically, the cost to buy a skid-steer loader and the VTS is a little less than the price of a compact track loader of comparable size, he reports.

The suspension feature of the VTS works like the torsion axles on a trailer, allowing the tracks on one side of the loader to move up and down independently of the other to maximize ground contact, improve stability, and make most efficient use of engine power, Kaspari explains.

The pentagonal profile shape of the track is designed to prevent the tracks from burying themselves in deep mud. “The front idler is placed significantly ahead of the front hub to improve stability when digging, backing out of trenches, or hauling and dumping heavy loads,” he says. “The rear idler is placed farther back of the rear hub for added stability when grading up inclines and traveling across side hills.”

Other features include an open design for ease of cleaning out dirt, mud, and other debris, and an optional, smooth, turf-style track to minimize ground disturbance when working on turf or golf courses. “The VTS undercarriage can be refurbished, if needed, at the end of the skid-steer’s useful life and reused on another make or model of skid-steer loader,” Kaspari says.

Loegering also supplies Genie Industries with its QTS system as an aftermarket option for its latest additions to its telescopic boom family—the S-60 and S-65 Trax models—in order to maximize usage of its wheeled models. This “flexible,” or interchangeable, track system is a set of four track undercarriages fastened directly onto a boom’s standard wheel hubs in place of the tires. With this option, customers are able to simply bolt on the tracks when needed and switch back to the traditional wheeled machine configuration when tracks are not needed. The entire system can be put on or taken off the booms in less than four hours. The addition of this option increases the machine width to 107 inches, which may require special transport permits. The undercarriages are constructed out of high-grade steel and feature fully sealed, greaseless bearings for minimum maintenance. The four-point track system also features an easy-grease tensioning system for fast, reliable track adjustment. And, to limit the amount of debris buildup during operation, V-shaped, self-cleaning pads are incorporated into the track design.

More information about the VTS, QTS, and the company’s over-the-tire steel and rubber tracks for skid-steer loaders is available at www.loegering.com.

Outfitting Excavators
Depending on make and model, tracks for excavators are available in three basic styles: steel, rubber, and a hybrid style that combines steel shoes with a rubber or polyurethane pad.

“If you’re working on dirt, steel tracks offer the most traction and are the most economical for general purpose work,” says Armando Najera, Komatsu America’s product manager for excavators. “However, for smooth surfaces, like asphalt or concrete, rubber tracks or those with rubber pads provide better traction and do not damage the surface.”

Width and length of the track affect both flotation and maneuverability. The wider the track shoe, the less ground pressure exerted by the machine and the better the flotation, he explains. However, as the track shoe gets wider, resistance to turning the machine as the tracks slide across the ground increases. “You could design a very wide track with very low ground pressure, but the resistance to turning would be so high that it would be almost impossible to maneuver the machine, not to mention the increased wear,” Najera says. “You could also increase flotation of a narrow track by increasing its length. But, that, too, would add resistance making it more difficult to turn the machine.”

In the case of steel tracks, the number of grousers and their height also affect machine performance. The shorter the grousers, the lower the traction and the higher the flotation, Najera explains. Steel dozer tracks, for example, typically have a single tall grouser. It will penetrate deeper into the ground under the weight of the machine for better traction than would two or three shorter grousers on the same shoe. In that case, each of the grousers would shoulder part of the machine’s total weight, resulting in less ground penetration per grouser and less traction.

The types of tracks used on Komatsu excavator are examples of the various styles available today for compact, midsized, and larger excavators.

The company’s steel excavator tracks feature double- and triple-grouser designs. The grouser height on this type of track is less than that on a single grouser. Tall grouser height provides traction and short grouser height provides flotation. Excavators use tracks primarily for moving from one work spot to another, which requires less traction than needed by dozers for pushing dirt. Double grousers are offered on larger excavators that require more traction than flotation due to their size and application.

In return, the double and triple-grouser designs offer increased track and machine stability. “Having two or three grousers prevents the shoes from flexing as much as one grouser for more stability. Also, it increases stability of the machine when lifting over the side of the excavator.

Rubber tracks are the only style available for Komatsu’s smaller compact excavators. Larger compact machines can be equipped with rubber tracks or Road-Liner track pads. The Road-Liner-type bolt-on shoe, which combines steel shoes with rubber or polyurethane pads for minimizing damage to concrete, asphalt, and other sensitive surfaces, is an option for several of the mid-size construction models.

More information is available at www.komatsuamerica.com.
About the Author

Greg Northcutt

Greg Northcutt writes frequently on construction and business issues.

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