All About Tires

It’s safe to say that the scrap industry couldn’t function without tires. After all, tires enable essential equipment such as forklifts, skid-steers, front-end-loaders, wheeled excavators, and trucks to do their jobs.
   But it’s also safe to say that scrap recycling facilities are some of the toughest environments on tires. Jagged pieces of scrap metal, harsh operating surfaces, and heavy usage are just some of the factors that conspire to shorten the lifespan of tires in scrap plants.
   “It’s the toughest work environment for construction equipment, and it’s the toughest work environment for a tire,” says Chris Vinson, marketing director for Super Grip Corp. (Piney Flats, Tenn.), one of several companies that make tires for scrap applications. (For a list of tire manufacturers for the scrap industry, see “Tires Are Us” on page 53.)
Some types of tires withstand scrap industry abuse better than others. Some are easier on your equipment and operators than others. Some cost more and/or last longer than others. Also, different recycling operations require different types of tires.
   One fact is clear, however: Choosing the wrong type of tire can be costly in terms of repairs, replacement-tire expenses, and downtime.
   So how do you select the best tires for your operations and equipment?

Reviewing Tire Types
Generally, three types of tires are used in scrap operations: pneumatic (or air-filled); foam-filled; and solid (including laminated tires).
   Pneumatic tires are most commonly used in over-the-road vehicles such as trucks because they provide a comfortable ride and superior control. Their downside is that they can be easily punctured, which isn’t a big problem on the road but can be an all-too-frequent problem inside a scrap plant.
   In the scrap industry, therefore, pneumatic tires are primarily used only on truck fleets and occasionally on in-plant equipment operated in clean, paved areas. For equipment used in harsher scrap plant conditions, pneumatics simply don’t last. “Every scrap yard that’s using pneumatic tires is getting rid of them,” asserts Vinson.
   Foam-filled tires, which—as the name suggests—are pneumatic-type tires filled with thick polyurethane foam instead of air, are more puncture-resistant and, thus, are more durable than air-filled pneumatics. Still, many operators maintain that foam-filled tires can’t withstand the roughest scrap conditions. Punctures or chunking can still occur, some say, and the foam can leak out.
   For extremely rough conditions, scrap processors usually turn to solid rubber tires. Atlas Metal & Iron Corp. (Denver), for example, uses the pneumatic tires its new equipment comes with, but once they’re spent, the firm buys solid tires, says Terry McReynolds, maintenance supervisor. Others agree that solid tires are generally the best choice for rugged plant operations.
   The solid tire category also encompasses laminated tires, which are made from high-quality sidewalls of bias-ply tires that are laminated together to form a tire. Production of these tires fell off as the supply of bias-ply tires dwindled after the introduction of steel-belted radials. Super Grip, however, has found a new supply of bias-ply tires in India, and it’s reintroducing laminated tires in the scrap industry.
   So, how do you decide which tires to use on specific equipment? And how can you choose one make of tire over another? The following criteria can help you make the right choice.

Weighing the Issues
The first thing to consider is the tire’s physical characteristics (such as construction and tread type) and field performance (encompassing cost, longevity, mobility, ride, stability, and clearance), says Bob Ochsenhirt, manager of off-the-road tire sales engineering for Goodyear Tire & Rubber Co. (Akron, Ohio). Depending on the application, pushing power, load capacity, and general reliability must also be considered. In considering that, it can be helpful to learn the basics of tire construction.
   Where the Rubber Meets the Road. Essentially, tires can be made from two kinds of rubber—natural (rubber that comes from rubber trees) and synthetic (rubber made from petroleum products). While most tires contain both types of rubber, industrial tires will often have a higher percentage of natural rubber in them because it’s less susceptible to heat.
   By varying the types of rubber compounds used, significant performance values can be achieved in wear, ride, rolling resistance, and load-carrying capacity. Not surprisingly, most tire manufacturers guard their specific rubber formulas closely.
   SETCO Solid Tire & Rim Assembly (Idabel, Okla.) says it uses 100-percent natural rubber in its solid tires and adds shredded wire with 70,000 psi tensile strength to the mixture, which reportedly strengthens the mechanical bond between the strands of rubber and helps prevent chunking in the tires.
   With foam-filled tires, there are not only differences in rubber formulations, but also variations in the foam filling itself. Galaxy Tire and Wheel Inc. (Malden, Mass.), for instance, fills some of its tires with a highly engineered orange-colored polyurethane foam that it calls “Poly Soft-Super Fill.”
   Aside from such physical characteristics, what factors should you consider in deciding whether to use a foam-filled or solid tire?
  The All-Important Application. One criterion is application—that is, where and how the equipment and its tires will be used.
“I think application is probably the number-one criterion,” says Jay Klempner, president and CEO of S&B Consulting L.L.C. (Louisville, Ky.) and a sales representative for Moros/North America. “Running a front-end loader in a shredding operation, for instance, is different than running a forklift in a nonferrous warehouse.” In the first application, a solid tire probably would work best, while the latter environment could allow a foam-filled or even a pneumatic tire.
   Application can also pertain to the type of equipment the tires will be used on. Some machines such as skid-steer loaders, for instance, are notoriously tough on tires, so their use often demands the strength of a solid tire. “On most of our front-end loaders, we go with foam-filled tires,” says Bill Clay, maintenance supervisor for Louis Padnos Iron & Metal Co. (Holland, Mich.). “But with the skid-steers and the really small loaders, we go with solid tires.”
   Generally, he says, the bigger pieces of equipment will get foam tires, especially on equipment that goes on the road. “If it’s just a straight dump truck, we use solid tires,” he asserts. 
   The Wear-and-Tear Factor. One of the biggest battles between foam-filled and solid tires is over the wear-and-tear issue—in other words, the effect of the tires on both equipment operators and the equipment itself.
   The general rule is that the harder the tire, the less comfortable the ride and the greater the negative effect on the operator and the equipment. A hard tire—one with little deflection, or give—transmits the bumps, bangs, and shocks of a scrap plant more directly to the operator as well as the equipment’s axles and other operating parts, which can lead to damage and fatigue.
   The challenge for tire manufacturers, therefore, has been to create tires that can deliver a comfortable ride while also having the durability to survive tough scrap conditions. Both foam-filled and solid tire makers say they’ve done just that.
   In the foam-filled niche, Galaxy Tire says its “Poly Soft-Super Fill” has a Shore Hardness of 6 durometers, which reportedly gives its tires “the exact same ride characteristics as an air-filled tire.”
In the solid-tire market, SETCO makes three types of solids that provide varying amounts of cushion. From its “Classic” solid, the ride gets softer with its “Soft Ride” model and softer still with its “Jelly Belly.” 
   SETCO cushions the ride of these tires by putting an inner core of softer rubber underneath the harder outer core, thus creating a shock-absorber effect and increasing the tire’s deflection.
   Other solid tires, such as Super Grip’s “Shockmaster,” achieve a softer ride in a different way. They have holes punched through them from one sidewall to the other. These air pockets increase the tire’s give as it rolls or runs over solid objects.
   It should be said that sometimes the wear-and-tear of a harder tire is worth it. It all comes down to whether the damage to the equipment will cost less than the tire repair or replacement costs. Klempner recalls using a laminated tire on a rough-terrain forklift in his plant. He concedes that the laminated tires were hard on his machine but they saved him money on the tire side. “I used up a lot of rear ends and axles, but it was cheaper than buying tires every week,” he notes.
   A Long and Healthy Life. How long a tire will last is always a top concern for scrap processors. A tire’s longevity is affected by many factors, of course, including the operator, the operating surface, the equipment, and more.
   Generally, though, the consensus is that solid tires last longer, sometimes a reported three to five times longer than pneumatics and foam-filled models.
   According to John Wolford, aftermarket manager of Super Grip, his solid tires can survive at least 1,000 to 2,000 hours on average in a scrap facility (even on tire-abusing equipment such as skid-steers), and he’s had testimonials that they’ve lasted as long as 3,500 hours. Pneumatic tires are lucky to last 300 to 400 hours, he says. Because of that, more scrap operations are turning to solid tires on equipment like front-end loaders, skid-steers, and forklifts. 
   Atlas Metal & Iron’s McReynolds says his company normally gets 1,600 to 1,800 hours, or about a year, out of a set of solid tires on a forklift. Rich Robertson, plant engineer at Annaco Inc. (Akron, Ohio), adds, “We tend to get at least two, possibly three, years out of a solid tire on loaders.” In contrast, a foam-filled tire may last a year, he states.
   From his experience, Klempner notes, “We used solid tires on the front-end loader at my shredder, and we found those to be long-lasting. They lasted about a year, sometimes more, sometimes less depending on if you were busy or not. On other front-end loaders at my ferrous operation, we used rubber tires that were foam-filled, which could last as long as two years.”
   As laminated tires work their way back into the scrap market, they could become an even longer-lasting option than current solid tires. In fact, boasts Super Grip, “In many cases, our laminated tires will outlast the equipment on which they are installed!”
   Paying the Price. The investment in a good set of tires can be hefty. Depending on its type and size, a set of tires can cost as little as $600 or as much as $15,000.
   “On a wheel loader, you’re talking well over $2,000 per tire,” says Robertson, whether it’s a solid rubber tire or the many-ply foam-filled tire the equipment would require. “If you have to replace them yearly, that’s $8,000 to $9,000, and that adds up.”
   Price can certainly be a determining factor in whether a scrap processor buys foam-filled or solid tires. In general, solid tires are more expensive than foam-filled, but sticker price isn’t a true reflection of a tire’s value. As solid tire manufacturers point out, solid tires can save the processor by preventing downtime due to tire failure and eliminating the need to maintain spare tires in inventory. As Robertson points out, “A solid costs a little more, but it lasts longer, so it really evens out.”

Taking Care
No matter how good a tire is, it won’t perform at its best unless it’s well-maintained and used properly.
   Some companies have incentive programs that reward operators who look after the tires on their equipment. Others train their employees to drive carefully and be aware of hazards. As McReynolds of Atlas Metal & Iron notes, “We haven’t had some of the problems some recyclers have had with solid tires, breaking steer axles and articulated parts. Generally, if there’s a spot in the plant that’s hard enough, the operator respects that. He knows when to slow down.”
   Training must also be provided if employees who operate the equipment are the same ones who change the tires: OSHA regulations require at least minimum training for employees who mount, dismount, inflate, deflate, or perform other rim and wheel service-related activities.
   Another step that can aid your tires and even give you more tire options is to hard-surface all operating areas of your plant.
   “We feel like we gained a lot by cementing our whole place,” says McReynolds. Though concrete has its drawbacks—it can wear down rubber and be hard on equipment undercarriages, for instance—it also helps keep operating surfaces clean and thus helps reduce tire damage.
   Taken together, all of this advice can help you find the right tire for your operators, equipment, and operations, which will enable you to focus on processing scrap rather than tending to tires. •