Forestry is one of the most demanding environments for tires. Feller bunchers and skidders are subject to muddy, steep slopes and sharp stumps while cutting and transporting trees to the landing site. With one weak link in this chain of operation, there is no load to transport and no money to be made.
Tires greatly impact performance in the forest, but not every setup is ideal for every forest setting, which is why loggers need to consult with their local dealer for the best solution.
Will Stoddard, forestry product specialist for Titan and Goodyear Farm Tires, recognizes that each logger has different needs, but they are all looking for the same two basic things from their tires—durability and performance.
“What might be a good solution for one logger, might not be for another,” explains Stoddard. “But in the end, everyone wants a tire that lasts longer and improves traction and flotation, and that’s what manufacturers are all working on to continually improve.”
Despite a desire for durability and longevity, many loggers have a tendency to choose the lowest priced option available. Many don’t realize the sacrifices they are potentially making by doing so.
“If they choose an undersized tire or too low of a ply rating, they’re going to wear that tire out pretty quickly,” says Stoddard.
Heavier Tires for Heavier Equipment
Forestry equipment has grown heavier and higher-powered—and as compared to a decade ago, many loggers are using bigger machines to do the work of two smaller machines.
“Machines today are up to 40,000 pounds and equipped with 12-foot, 10,000-pound grapples; whereas five years ago, machines were 25 to 30 percent lighter,” says Stoddard. “The issue is that OEMs (original equipment manufacturers) are still offering the same ply tires they were years ago on those smaller machines.”
Tire manufacturers have adjusted by introducing larger and higher-ply tires. Not only do the tires have to carry the weight of the bigger machine, they have to endure twice the punishment. However, it’s easier for OEMs to equip the lowest-ply tire for the lowest cost—but that is a mistake.
“The temptation by the OEM is to offer a lower-ply tire in order to control the machine’s cost coming out of the factory,” says Stoddard. “And most loggers will have the temptation to go with the lowest priced option when buying a new machine. But once it hits the ground, the logger is expecting to get greater productivity, with a grapple on back and greater drag capabilities than what it can handle. We’re ‘ply-ing up’ those same machines to get as high a ply as possible for increased strength.”
Stoddard recommends tires with higher ply ratings—usually either 20- or 26-ply in a 30.5L-32 or 35.5L-32 size. Even though the heavier tires are a little more expensive, the cost is well justified over time, because they last longer.
“We are constantly evaluating and looking to address the continued trend of larger, more powerful forestry machines that are going to have greater demand and requirements from their tires,” says Stoddard. “In fact, we’re currently testing 30- and 32-ply tires that we plan to roll out sometime in 2018—and we’re seeing excellent results.”
Ply ratings and tire size are not the only design factors that affect durability. Tire manufacturers are working to build stronger forestry tires through development of new technologies—both in steel-belt packages and rubber compounds.
Designing for durability
In the last ten years, steel-belt constructions have become the standard for forestry tires, because of their ability to protect from punctures.
“Forestry tires require a very high void-to-lug ratio in order to gain traction. In these voids, there is less rubber between the ground and the tire plies, which makes those areas susceptible to puncture damage from branches and stumps,” says Stoddard. “So all the major tire manufacturers are working to develop stronger steel-belt packages that offer additional protection between the lugs.”
Some of the most recent developments in the industry include a shift from two-belt to four-belt constructions and the development of steel belts that offer more flex.
“All the tire manufacturers want their steel belts to be strong enough to resist punctures, yet not so stiff that they break,” explains Stoddard. “It’s really a balancing act that everyone in the industry is working to continuously improve.”
Another problem challenging tire longevity is damage to the treads. Constantly running over sharp branches and stumps can cause the rubber to chunk and tear — a problem that tire manufacturers are addressing through the development of special rubber compounds.
“Most of the major tire manufacturers have developed rubber compounds specific to forestry that are designed to limit damage to the treads,” says Stoddard. “Regardless of the brand you choose, I’d definitely recommend choosing a tire with a compound designed specifically to meet the unique challenges faced in the forest.”
Another trend that affects tire durability is the increased use of tubeless tires in forestry.
Is Tubing Necessary?
Tube-type tires have been an industry standard for years. But in recent years, more tires are coming out of the factory tubeless. While both types run at the same inflation pressures and load capacities, their major differences lie in cost and reparability.
“In the forest, tubes are a good idea because of the harsh conditions pushing the beads off the rim band,” says Stoddard. “This causes potential for the tire to go flat. A tube maintains the tire and keeps it going.”
Tubeless tires are more expensive than tube-type tires, but tubeless tires are easier to repair, as you can keep repairing them until they no longer hold air.
When it comes to using tubes, Stoddard has seen a lot of different philosophies from OEMs outfitting their equipment.
“Some run tubeless tires with tubes for all of their tires, others run tubes only if a customer specifically requests that the tubeless tires have tubes put in them. Other OEMs run tubeless tires and only put tubes in them if using a dual setup,” Stoddard says. “The OEMs try to offer what their customer base is asking for. A few OEMs offer the tube-type with tubes as an option, because some users just prefer to run a tube-type tire from day one.”
Regardless of philosophy, Stoddard says there is one necessary rule everyone should follow — duals require tubes. Duals kick up a lot of debris between the tires, and that debris is always pushing on the inside tire. If the inside tire loses pressure, it’s going to push that tire off the wheel, and then you’ve got a flat. That’s why tubes are a must-have with dual setups.
Extreme Flotation or Duals?
While the sheer weight of today’s equipment helps with traction, it also poses a new challenge—the need for flotation.
Tire setup can be very weather-dependent and location-specific. If you’re in an area that doesn’t require flotation 100 percent of the time, then duals may be a good option, because you have the flexibility to easily take the outer tire off and run the single when conditions don’t require it. That way you’re not putting wear on those extra two tires when it’s not necessary. With duals, however, you may have to sacrifice ease of maintenance.
“The outside tire in a dual setup completely rests up against the inside tire. There is no way to access the inside valve unless removing that outer dual. So most loggers won’t take the time to take the tire off to check air pressures,” Stoddard says.
Because there are no shocks to absorb the impact of the machine, operator tendency may be to run it at a lower inflation pressure for a softer ride, but if it’s too low, there’s a higher probability of a tire problem down the road—especially when you’re not able to check that inside tire pressure on a regular basis on a dual setup.
If you’re in an area that requires flotation 100 percent of the time, you’d benefit from running super singles, because it’s easier to manage inflation pressures.
“In order to increase flotation, you have to decrease the ground-bearing pressure. You do that by spreading the pressure out over a wider area,” says Stoddard. “So there are flotation tires on the market that — in many cases—are roughly 10 inches wider than standard forestry tires. The wide footprint helps with flotation in wet or swampy forests.”
Maintaining Your Tires
Stoddard insists the most important thing loggers can do to ensure tire longevity is to keep their tires at the proper inflation pressures.
“Inflation pressure is something most loggers need to pay much more attention to,” says Stoddard. “An underinflated tire can cause the sidewall to bulge and lead to stress cracks around the sidewall and lugs. It can also cause problems with slippage on the wheel. An overinflated tire will swell in the middle and won’t flex when running over stumps. That increases the likelihood of impact damage.”
Stoddard also recommends routinely inspecting the tires between shifts.
It’s important to seek the advice of your local dealer. Sometimes the cheapest tire or the tire that came installed on the OEM equipment is not always the best option for durability and performance in your neck of the woods.
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