An industry left breathless: Technology setting the stage for airless tire emergence

There is something about this moment. Something about the technology, innovation, materials and insights.

Something is happening and it's leaving the tire industry—or at least some of its tires—breathless.

"Why is there so much excitement with this?" Jon Kimpel, Bridgestone Americas vice president of extended mobility solutions, said about the nonpneumatic tire technology emerging in the passenger car and commercial truck/bus tire space. "It is something which once appeared to be decades away, and it is less than decades now."

The world's three largest tire makers—Michelin, Bridgestone and Goodyear—each have pledged to bring a viable airless tire to the market within the next five years. And while each is targeting a different vehicle segment today in pursuit of that North Star, they say shifts in material science, auto industry technology and customer/consumer expectations are making that possible.

Michael Rachita, senior program manager on Goodyear's nonpneumatic tires team, would be among the first to admit how exciting it is to work in the innovative airless tire space. Especially when that technology is combined with the advancements in vehicle technology—primarily electrification and autonomy.

But what gets lost in the shuffle, he said, is the fact that airless tire technology isn't new.

It's advancing.

"You can go and get Tweels right now," Rachita said. "There are a lot of markets that are using these engineered airless tires that are off-road, mainly industrial applications."

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About 20 years ago, Michelin engineers Steve Cron and Tim Rhyne puzzled out the nonpneumatic tire conundrum by reimagining the space between the tread and the rim. Instead of attaching the tire's sidewalls using beads and filling the empty space with air, the duo designed a polyurethane spoke-like structure that connected between the rim and the tread. The concept called on the physical materials to do the heavy lifting that air had done for more than a century.

And that concept, Rachita said, is fascinating.

"One of the hardest things to do is—as you start to look at airless tire technology—is can you load the vehicle with a solid structure that still performs like a soft, compliant air tire?" he said. "… And the bigger the vehicle—like that 18-wheel truck—the harder it is to do, given the stress into the system, the stress into the type of material."

With Tweel, Michelin proved that the airless tire concept was more than viable. It works. And works well.

Now, it's up to the industry overall to take the technology further—and make it even bigger.

"It is amazing how much work air does in a pneumatic tire," Kimpel said. "Especially in a truck application with 120 psi of air. That is a lot of energy. And so, when you go and replace all of that energy with a material, it really has to be an efficient material."

That's a feat much easier said than done.

Because finding the right material—one that covers all the bases for a fully sustainable, nonpneumatic tire—is tricky, according to Brandon Nelson, manager of advanced extended mobility technology at Bridgestone Americas. During a May 31 conversation that was part of the tire maker's Thrive podcast series, Nelson explained the challenges of bringing the right materials—those with exactly the right performances—to Bridgestone's proprietary Air Free tire development.

"That is one of the drawbacks when we start to use materials to carry the load," Nelson said. "Naturally, most materials—and most materials that flex enough to be a tire—are going to be lossy, and they are going to drag as you go down the road.

"We have focused on that from the very beginning, going to loss-less materials," Nelson added. "But as you go to loss-less materials, you start to have trouble handling impacts, handling natural undulations in the road. That has been a lot of the focus in the last few years, making those materials—which give us the efficiency we need—also be robust enough to handle what they are going to see out on the road."

The key to optimizing a nonpneumatic tire doesn't so much require tinkering with tread compounds as much as it does with perfecting that connecting structure, Rachita said.

The structure needs not only the right materials, but the right design for stability and give.

"The tread area, for the most part, is exactly the same as traditional tread compounds. We have not redeveloped rubber compounds. A great winter compound or a great summer compound or a long-lasting treadwear is going to perform the same," Rachita said.

"Because part of what we are doing is trying to design the footprint pressures and the types of footprint that a normal tire—an air tire—achieves, but with the physical architecture," Rachita added. "So if you get the footprint pressures and distributions correct the tread compound should perform the same.

"So we put all the great compounding at Goodyear behind the rubber components within (the airless tire). Then it became more of this mechanical design. How do you think like an architect? How do you think like a systems engineer and bring this whole thing together?"

Bridgestone, Goodyear and Michelin have forayed into the airless tire development space, albeit in very different ways.

Michelin's journey began in the niche OTR space, where Tweel has conquered smaller-size tire applications for everything from lawn mowers to small construction equipment.

"You can find (Tweel) on lawn mowers, you can find it on ATVs and on utility vehicles. A lot of application is in the military space," Alexis Garcin, Michelin North America chairman and CEO, told Cheddar News in January about the company's airless tire development. "So it already is something that we are putting on the ground."

Michelin declined an opportunity to discuss its nonpneumatic tire journey with Rubber News at this time, but it has publicly signaled how it plans to move forward with development of passenger tires, particularly for the EV space with its Uptis prototype.

Goodyear, meanwhile, has made significant strides in its airless tire development. And it has done so by casting a wide net—unveiling products that meet the unique needs of fleets both large and small.

"You will see (Goodyear's airless tires) on the microdelivery robots right now," Rachita said, referencing the Akron-based tire maker's partnership with Starship, a startup focused on autonomous robots that deliver food and goods across college campuses. "We have tires right now in the field. We were partnered with Jacksonville, Fla., where they were operating autonomous shuttles with our airless tires."

Bridgestone, on the other hand, is thinking much bigger.

"We took a look at: OK, where is the biggest value for an Air Free technology within this space?" Kimpel said. "… And we decided that, today, the biggest need is more in the fleet market, the trucking market. Especially in the trailer position, which tends to be a lower maintained wheel position, especially when it comes to air pressure.

"So we have been focusing a lot more of our efforts on the trucking industry, but with the sight that we can go and take that and apply that modeling and design and materials science to other applications in the future, like autonomous vehicles."

When nonpneumatic tire technology began to break through just about two decades ago, there wasn't really a necessity behind it. It was innovation and disruption rolled into an ingenious concept.

"A lot of that (early development) was motivated by disruption," Rachita said. "Can we disrupt our own industry by looking at, you know, an airless tire architecture? Can we reimagine a tire?"

Now, the disruption is coming from a different side—the auto makers themselves. And that disruption is, perhaps, the greatest driver in nonpneumatic tire development.

Because the auto industry is in the midst of its own transition. OEMs are racing to embrace technologies around electrification and autonomy, transition production for EVs and eliminate internal combustion engines from their lineups in the process.

And that revolution, tire makers say, is changing the game for them, too.

"There is a momentum that really has come from the autonomous vehicle fleets, so that as we move from electrification into AVs, maintenance-free is almost a requirement," Rachita said. "... If an autonomous vehicle without a driver in it were to stop because of a tire issue or whatever, that vehicle is no longer working the way it is supposed to work.

"So they are asking if there is a different way for us to look at the tire. And we're like, 'Yes. There absolutely is. Here is our tire technology without air.' That is the shift or the pivot."

Michelin has touted its Uptis technology as the perfect solution for electric models. The tire maker, in 2019, partnered closely with General Motors for the development and real-world testing of its Uptis airless prototype.

From the start, that partnership has focused on Uptis as a fitment for the Chevy Bolt. And Michelin touted the maintenance-free benefits of Uptis as a reason for that.

But it works for autonomous vehicles, too.

"Uptis delivers a high level of comfort and safety and eliminates the burden associated with tire maintenance, making it a key asset for emerging collective mobility applications, such as autonomous shuttles and shared vehicle fleets," Michelin says on its website.

The idea of maintenance-free tires is something that Kimpel contends benefits fleets across the board—electrified, autonomous or ICE.

"For us, that is where we saw a lot of benefit when it comes to removing that variable of air," Kimpel said. "When it comes to the downtime associated with it, and all of the additional maintenance that air requires, that is what has driven us from our initial discussion with both the OE customers and our fleet customers."

One major reason for Bridgestone's success in its Air Free tire development, Kimpel said, is the advancements in tire modeling. Without exceptional computer simulation and modeling, the project would be light years behind.

"In the past five years, and I can definitely speak about Bridgestone, just the advancement and material science—but especially in the modeling side, that is what really has progressed it to the point where we could do hundreds of prototypes within a couple of weeks as opposed to doing physical prototypes," Kimpel said. "That really sped things along for us."

Kimpel noted Bridgestone's nonpneumatic tire team is aiming for a "controlled launch" of Air Free tires with trucking fleets as early as 2025.

To achieve this, the team has been testing and modeling in Akron, but hopes to bring testing to the company's Texas Proving Grounds by the end of this year. The ultimate goal is to expand fleet trials sometime in 2023 before the controlled launch of the Air Free tire product two years later.

And all of that is a result of exceptional tire modeling.

"It is becoming very, very real," Kimpel said.

Rolling out an airless tire technology is one thing. Selling it is another.

Because while nonpneumatic tires may offer practicality from safety, reliability, sustainability and time management perspectives, when it comes to cost parity, they likely aren't going to match traditional pneumatic tires any time soon.

"From a technical standpoint air is really efficient and it's free," Kimpel said. "And so, when you are going and removing that, you are going to have to—again—find a very efficient material to replace it. … You are adding material and there is cost associated with any type of material that you are going to add."

Because nonpneumatic tires are likely to cost more than traditional pneumatic tires for quite some time, it is unlikely that most consumers are going to willingly make the switch. At least, right away.

"Cost parity would be important," Rachita said. "We are not at scale. We can't compete with hundreds of millions of (pneumatic) tires—a process that has been optimized for 30-40 years. Cost parity is something that would take years to come."

Plus, both Kimpel and Rachita also noted that it will take time to scale production of nonpneumatic tires. And all of those investments would hinge on the particular design and construction of the tire being brought to the market.

"We do have (a plan) for how we go from ideation to incubation, accelerate and scale. We have an overall process there," Kimpel said. "… We will have to ramp up and get to 'how do we get to that kind of scale?' We can see it being pretty significant demand for a product like this."

Even if everything falls into place and all three tire makers hit their airless tire rollout goals, bringing the tires to market within three to five years, Rachita isn't convinced these rollouts will impact the largest swath of motorists.

The nonpneumatic tire revolution, he said, is more likely to be an evolution.

"We see it as more of an evolutionary change," Rachita said. "At one point there were thoughts of: Could it be disruption? We see it more like things like antilock braking systems. You know, at some point, we didn't have ABS, and then high-end vehicles got ABS, and then more vehicle classes got ABS … and that took 20 or 30 years.

"This is 20 to 30 years of evolution, of moving the (entire) industry toward a safer and more maintenance-free option."

Ultimately, Rachita said, airless tires will find their place within just about every segment of the tire industry, and this moment of evolution and innovation certainly marks their time to shine.

Still, air-filled tires can breathe a sigh of relief.

"The pneumatic tire is not going away any time soon," Rachita said. "It is a wonderful, wonderful product that we have optimized. And it is a powerful product for human society. Everyone around the world depends on air tires for mobility."