Big Wheels, Big Deals
Forestry Tires: Proper Selection, Use, Care of Tires Can Reduce Costs, Increase Productivity; Suggestions from Firestone
New Firestone Tire Better Match for Bigger Machines
In the business world of the 2000s, small increases in efficiency can add up to the difference between profit and loss. Most loggers know this, so they pay attention to the type of machinery they use to harvest the forest, make sure engines and hydraulics are tended to on a regular schedule — and, unfortunately, regularly neglect their tires.
On a typical logging operation, tens of thousands of dollars may be invested in tires. Yet proper tire maintenance often is overlooked, much to the detriment of the logging contractor’s ability to turn a profit, according to Stu Miller, a Firestone senior project engineer who is responsible for forestry and flotation tire development. Loggers who do pay attention to tire selection, train their operators about good driving techniques, and take the time to assure on-going maintenance is done can impact profitability significantly, he said.
Tire selection often is an overlooked aspect of efficient machinery operation, Stu contended. The region, type of job, and the sensitivity of the forest floor to rutting and compaction all play a part in determining which tire will best do the job, he said. The logging contractor who takes the time to select the correct tire for the special conditions unique to his application can reduce costs and increase productivity.
As an example of the importance of tire selection, Stu pointed to a particular problem with the tire that has been the standard in the woods for years — the 28-L-26 forestry tire. The 28-L-26 served the forest products industry well for years, Stu noted, but in the last decade or so forestry machines have become larger and their loads, heavier. Timber harvesters, however, have not adjusted to the changing conditions. “As a result,” Stu said, “they are overworking a tire that everyone has been used to using for years.”
In light to moderate service, Stu said, the 28-L-26 still is a great tire, and because of the cost, it frequently comes standard on a new forestry machine. When pressed into heavier service, however, he believes the tire sometimes comes up short. “Firestone’s 30.5-L-32 is often more appropriate for the bigger machines of today,” he continued. “The harvesting contractors we have seen using them are getting more hours of service, fewer cuts and punctures, and superior production.”
While loggers may object to the higher cost of a larger tire, overloading a tire that is too small results in increased wear, spinning, and tire separation, Stu observed — which all reduce productivity and increase costs of wear and tear on expensive machinery. Their cumulative impact over the life of a tire may be several times more costly than the difference in the price of a larger, more serviceable tire.
Operator training is also an often overlooked factor in forestry tire performance, according to Stu. “I think the owner or manager of any operation ought to go out and watch their operators on a job from time to time,” he said. “It’s amazing how much difference there is between operators, and I can guarantee you the way a machine is operated has a very substantial impact not only on how long the tires last but also on productivity and on the life of the machinery.”
The operator who avoids excessive backing up, spinning of tires, and jerky movement will save the contractor more money in extended tire life and increased production, said Stu. There are techniques for running a machine smoothly, he noted, and the machinery operator who either does not learn them or ignores them is costing his boss money.
Perhaps the most important aspect of selecting and using forestry tires to increase profitability is proper tire maintenance, said Stu. It is amazing, he noted, how many logging contractors will have an established preventive maintenance schedule for changing oil, checking hydraulics, and performing other tasks on an expensive machine and then completely ignore the tires. A contractor may have $10,000 invested in a set of tires. Anything that extends the life or improves the productivity of that investment contributes significantly to the overall profitability of the business.
The most important thing in proper tire maintenance is tire pressure. Over time, all tires lose some air pressure. Running machinery on tires that are not inflated to recommended levels of air pressure causes excessive wear, tire separation, and tire-rim slip. The result is reduced tire life, loss of productivity, and increased operating costs. “Tire pressure is such an easy thing to track on a routine basis,” said Stu. “Why would anyone want to accept the increased costs that failing to pay attention to proper pressure can lead to?”
Tires also should be visually inspected for cuts that can lead to tire failure. It is the nature of the logging business that forestry tires are going to get cut, said Stu, although many cuts are only surface cuts. Routine maintenance can lead to discovering deeper cuts that have exposed plies; in cases of this type of damage, removing the tire and repairing it immediately can extend the life of the tire, increasing profitability.
The key to making money on a timber harvesting job is for the machinery to be running, Stu noted, and proper tire maintenance can help ensure the equipment and job keep going. It is better to find and fix tire problems before they show up on the job. A skidder that is deep in the woods with a bad tire is a costly problem, he pointed out. The downtime and expense associated with fixing it justifies a careful program of routine maintenance aimed at avoiding tire problems.
A major issue for loggers in recent years has been treading lightly on the land. Traditional tires and logging techniques cut ruts in and tear up the forest floor as well as compact the soil they run over. Excessive rutting leads to erosion and pooling of water while excessive compaction makes it difficult for new trees to grow and thrive.
In order to avoid excessive rutting and compaction, Stu at Firestone and other tire engineers have invested considerable portions of their careers into developing what have become known as “flotation” tires. Flotation tires are broad tires that spread the weight of the load across a wider amount of ground, reducing both compaction and rutting. Studies show that flotation tires are very successful in reducing these negative impacts of logging, and many land owners and regulatory authorities now require them.
An alternative to flotation tires is running dual tires. Dual tires also spread the load over a wide footprint, but they are a more flexible option since the extra tires can be removed, depending on the nature of the job.
Both flotation tires and dual tires are a vast improvement over old practices, noted Stu, who added that the specific requirements of a job should dictate the choice. In general, he said, studies have shown that if a softer footprint is of primary importance, the flotation tire will out-perform any other configuration, including dual tires. “For environmental protection, the flotation tires are clearly superior,” he said.
Buddy Gilman, owner of Gilman Logging in the central Virginia town of Ashland, has used both standard and high flotation tires. Three of his four Timberjack skidders are equipped with Firestone high flotation 44-inch tires while the fourth, which is used as a yard machine, is equipped with 32-inch tires. The difference in the woods is substantial, according to Buddy. “When I changed from the standard tires to the large flotation tires, it was a big cost for me,” he said. “But I’ve found that in the woods I work in they last longer and definitely do the job in not tearing up the ground. I also think we get a lot better traction with them, so we can operate in areas it was difficult to work in before.”
Flotation tires are important to his customers and state regulators, said Buddy. “Back three or four years ago the (state) forestry department got really strict on the rutting and compaction,” he said. “I decided to go with the bigger tires then, and they’ ve really done the job for me. This area of Virginia is fairly flat, and especially in the winter time we were running into some very wet conditions. The larger tires give us better traction so we can work in conditions we could not work in before. That’s important to me because we try to operate 12 months out of the year.”
Of course, the terrain that Buddy works on is different than conditions in other regions of the country. That’s why a local tire dealer can be an important resource to a harvesting contractor, Stu pointed out.
In addition to having the heavy machinery, equipment and expertise needed to repair large forestry tires, a local tire dealer is a valuable source of information, according to Stu. Correct tire pressure, for instance, will vary according to local area and conditions. The tire dealer, backed by the research efforts of a company like Firestone, can provide information about what kind of pressure level is best for certain conditions. That information, combined with the tire dealer’s knowledge of the experience of other loggers, gives the dealer a unique perspective on how changes in air pressure, tire configuration, or usage might best enhance a logger’s operation. “The local dealer acts as an information base for the logger,” Stu said. “It is one of the most valuable services a dealer has to offer.”
With some forestry machines costing a half million dollars and using computer technology, tires might seem like a small matter. However, loggers who pay attention to the tires on their machines will have a leg up on the competition, according to Stu. The contractor who selects the correct tire and maintains it properly will benefit from enhanced productivity, longer machine life, and improved profitability.
Firestone Recommendations for Better Performance
Stu Miller, Firestone senior project engineer, offered a number of suggestions for contractors in the forest products industry faced with the following tire-related problems.
Lack of Traction
• Lower inflation pressure to match the load on the tire.
• Replace worn tires.
• Reduce tire spinning by reducing overloads and/or reviewing operator techniques.
• Consider the possibility that tire chains might be indicated.
• Utilize dual tire or flotation tires for increased footprint in wet or soft soil conditions.
Tire Separation
• Increase pressure to match the load on the tire.
• Reduce overloading.
• Go to a higher ply rating or a larger tire.
• Repair cuts; unrepaired cuts over time may work along tread plies or body plies and begin to look like a separation.
Tire-Rim Slip
• Use approved mounting lubricant.
• Increase inflation pressure to match the load on the tire.
• Check knurling on the rims.
• As a field fix, use innertube pieces between bead and rim.
• Avoid trash build-up between rim flange and tire bead.
• Use a larger bead diameter tire.
• Reduce load for less torque on the tire-rim assembly.
• Discontinue the use of chains.
Tread Wears Too Rapidly
• Match inflation pressure to load on tire.
• Reduce tire spinning by reviewing operator techniques or reducing overloading.
• Move to a larger tire.
• If there is severe cutting, consider tire chains.
Excessive Punctures or Cuts
• Lower pressure to match the load on the tire.
• Use higher ply ratings or a larger tire size.
• Reduce tire spinning by reducing overloading or reviewing operator techniques.
• Consider tire chains.
Stu also offered these guidelines for routine maintenance that can improve performance and enhance tire life. He said contractors should:
• Check air pressure routinely.
• Don’t run “leakers.”
• Repair tires to extend tire life.
• Minimize tire spinning.
• Avoid excessive trash build-up between rim flange and tire bead
Firestone Sponsors Contest to Find Oldest Air Spring in Use
Firestone Industrial Products is conducting a contest to find the oldest, continuously-running air spring — Firestone Airstroke® actuators and Airmount® isolators — in an industrial application in North America.
“We want to show engineers and end users that air springs are low-maintenance, low-cost alternatives to pneumatic or hydraulic metal-walled cylinders for actuation — as well as other products for isolation, such as coil springs,” said Don Foulke, Firestone manager of industrial sales and marketing.
“Most importantly, they will last for literally millions of cycles. Combined with a lower initial cost in many applications and lower maintenance, the air spring is a bargain that, over time, will pay dividends in cost savings and benefits.”
The contestant who finds the oldest, continuously running air spring will win a week’s vacation for two in the Caribbean, complete with air fare, hotel and accommodations.
Firestone air springs were first developed for transportation applications in the 1930s as tough, long-lasting suspension devices for businesses, automobiles and trucks. They proved successful in helping improve ride quality, reducing freight damage — and claims — and reducing vehicle wear and tear by isolating road vibration.
In the 1940s the same products were put into use in industrial applications as Airstroke actuators and Airmount isolators. Since then, new shapes and sizes have been added to the product line
along with high-temperature resistant materials.
Airstroke actuators and Airmount isolators are well suited to applications that have limited space requirements. Metal-walled cylinders require clearance greater than the length of the stroke, but the Firestone Airstroke actuator compresses to a height that often is less than half the required stroke, enabling it to fit into tight places. It also can withstand off-set or unbalanced loads that tend to score or bend cylinder rods.
The winner of the contest will be announced at the Design Engineering Show in 2001.
For more information or to obtain a copy of the contest rules and application form, call Firestone applications engineer Brian Hoaglan at (317) 818-8745 or visit the Web site at www.firestoneindustrial.com.
