Solid tires gain traction in severe service applications

AKRON — Solid specialty tires have been growing in popularity among materials handlers, construction contractors and others looking to reduce down time and boost profits, according to tire makers active in the sector.

The resurgence of the construction industry amid a booming economy has been a major contributor to the increase of solid tire use, according to Alliance Tire Group (ATG).

"Since their introduction on the market, demand for solid tires has grown steadily because of their long life and durability, not to mention their increased load carrying capacity," said Ryan Lopes, national product manager, material handling and solid tires, for Alliance Tire Americas Inc. (ATA).

"Rather than a shift (in popularity), I think we're seeing a steady growth in awareness of where solid tires can help cut costs and improve profitability. Industries where we see the heaviest use of solid tires, like warehouses, logistics centers and waste management sites, all benefit from tires that last longer, are puncture-proof and function well in two- and three-shift environments."

Continental Tire the Americas said it has not seen a major overall shift to solid tires in recent years but said solid tires make up a significant portion of its industrial tire business.

"Specific industries where applications are harsh and punctures happen often have been moving toward solid tires. There are certain benefits that fleets receive by changing to solid tires, such as stability, puncture resistance and low maintenance, but there are sometimes trade-offs as well," a Conti spokesperson said.

The improving U.S. economy seems to be a key driver in growth in specialty tires.

"With the explosive growth of warehouse and logistics industries, the growth in the need for solid industrial tires is self-evident," Mr. Lopes said. "The stability, long life, high load-carrying capacity and puncture-proof nature of solid tires make them the perfect solution to support these businesses where cutting costs is critical."

Other industries, such as construction and demolition, are increasingly using solid tires over pneumatic tires, Mr. Lopes said, noting there also is growing demand for solid tires in waste handling, recycling, scrap metal yards, steel mills and landscaping, where vehicles must traverse broken pavement, rubble, debris and rock.

"I've been in this business a long time, and we used to sell a lot more pneumatic tires than we do now. We sell a lot more solid tires than we used to," said Benton Hood, president of Mitchell Industrial Tire Co. Inc. (MITCO), estimating that about 90 percent of his tire sales are solid vs. pneumatic.

"It used to be about 33 percent of what we sold was pneumatics but not anymore. It's reduced quite a bit."

He said the shift to solid tires is based on customers' desire to eliminate downtime related to flat tires.

In extreme conditions, solid tires will outlast pneumatics as well as foam-filled tires, so they provide the best total cost of ownership in high-intensity applications, Mr. Lopes said.

Specialty tire and track maker Camso Ltd. said solid tires are growing in popularity beyond just skid- steer loaders, noting on its website that solid tires are now viable for other construction equipment, including telescopic handlers, compact wheel loaders and full-sized wheel loaders.

MITCO's Mr. Hood said construction companies are big adopters of solid tires, especially for telehandlers.

The economy has helped boost the solid tire trend for forklift, construction, trailers and even airport operations, he said.

"We manufacture tires for jetways, and they were always pneumatic tires," he said, noting that many airports have switched to solid tires out of safety concerns.

"We have manufactured and sold a tremendous number of jetway tires and they have changed the configuration again to a solid press-on tire,…which I think is a better technology for that piece of equipment."

The engineering of apertures or holes into the solid tires is playing a major role in enhancing the operator comfort and the popularity of highly specialized tires, according to Camso, noting the price is now similar to that of foam-filled tires.

Group Michelin is in the process of acquiring Camso and combining its activities with its own OTR activities to create what it claims will the leading OTR/industrial tire group worldwide.

Solid economics

"We are always working with our customers to consider the TCO (total cost of ownership) against the initial acquisition cost of a tire," Mr. Lopes said.

"The conditions of the application and the intensity of tire use are the most critical factors to consider when determining whether it's pneumatic bias, pneumatic radial or solid tires that will provide the maximum possible benefit."

MITCO's Mr. Hood added, "It's just economics. A solid tire lasts a lot longer and much less maintenance potential.

"There are some downsides to it — deflection, traction, ride comfort, you can't go as fast. There are certain negatives. But you got a piece of equipment that you're earning a few thousand dollars an hour on. Every hour it's down, you got a major problem. Even the large sizes, the OTR sizes…a lot of those are moving to solid tires, particularly in junk yards where they run over a lot of things," he said.

"As an organization, we aspire to double our revenues over the next few years, and we've identified solid tires as an area of opportunity to help achieve this growth," ATA's Mr. Lopes said.

"Our Galaxy brand is known for application-specific, purpose-built construction and industrial tires, and we are committed to creating tires that help our customers solve the real-world issues they face in their day to day operations.

"An example of our commitment to our customers is the Galaxy Hulk SDS Skid steer tire, which was developed with a 16-inch rim diameter instead of the standard 20-inch rim diameter — but whose outer dimensions are the same as the 20-inch tire. The 16-inch rim diameter allows us to put on more rubber per tire, allowing the tire to last longer and reducing the number of costly tire changeovers.

"We designed that smaller solid construction specifically for the machinery and severe-duty applications seen in the waste/recycling and scrap-yard industries."

Disadvantages

A downside of operating with solid tires is that they don't operate very well at high speeds.

"So you have a trade-off there of down time vs. a little bit slower movement on the equipment," MITCO's Mr. Hood said. "If you're driving at the same speed you do on pneumatic tires, generally, they'll heat up in the center, and they'll blow out."

He said it depends on the company's operations whether slower speed is better than down time.

"All I know is more and more people are going to solid tires, so evidently it does. You're talking about a piece of equipment that won't go more than 15 mph anyhow. So if you dumb it down to say 8 mph, you're not going to lose 50 percent of your production because the truck is parked a lot," Mr. Hood said.

"The biggest downside to a solid tire, besides you can't go fast, is that you don't get the same traction with the solid tire that you're going to get with a pneumatic tire because you get virtually no deflection," he said.

"It's true that solid tires don't cushion machinery the way pneumatic tires do," Mr. Lopes added. "However, improvements in design and construction of solid tires — for instance, the use of apertures or three-layer construction that contains a cushioning compound like we use in our Galaxy Yardmaster SDS forklift tire — are extremely effective at protecting equipment and operators from excessive shock."

Conti said one trade-off that is not always readily considered is roll over protection standards (ROPS) that all equipment OEMs must calculate for safe use of vehicles. It's important for users to know whether the additional weight of the solid tire creates any problems with ROPS ratings, the company said.

Design challenges

With solid tires, the load is carried by rubber, while in a pneumatic tire, the load is supported by the air inside the carcass.

Engineering, special compounds and quality control are required for developing solid tires, where heat buildup caused by the density of rubber in the tire can result in rapid wear or even failure.

"A properly built solid tire manages heat buildup and allows operators to use their equipment at optimum speeds required for the machinery while improving overall equipment productivity," Mr. Lopes said.

"Because of its extra material and construction, a solid tire could cost a customer two to four times more than a pneumatic tire," Mr. Lopes said. "That is why we build our solid tires to deliver three to five times more service life than pneumatics."

Solid tires normally can be used beyond the non-skid depth, which is when a traction tire starts to look like a smooth tire, right up to the 60J mark, or "safety line," he said.

But ATA developed deeper non-skid tread in its Hulk SDS after customers asked for more lug depth to increase traction life. He said it was a challenge to create a deeper lug without creating excess heat, wear or cracking.

"The Hulk SDS is a significant technological achievement, and it is all geared toward providing a longer service life and better cost of ownership for our customers."

Conti noted that some of the trade-offs that a fleet can experience when moving to solid tires are ride quality and reduced heat dissipation. The tire maker said it has been addressing these issues by enhancing compounds and multi-stage tire designs.

A multi-stage tire has different compounds in its construction: the inner compound can maximize ride quality (cushion) and heat dissipation, while the outer or tread compound can be robust to reduce damage and increase total hours.

"We recently introduced an industry-first 28-inch solid tire for telehandlers called the TeleMaster. This tire uses our latest technology to maximize ride quality, hours of operation and robustness while effectively dissipating heat on longer and heavier load applications," the Conti spokesperson said.

"Generally speaking, cross-ply or bias pneumatic tires are the lowest cost and use older technology. Due to the complex compounds and total material required to make solid tires, they generally cost more to manufacture than pneumatic cross-ply tires."