"One of the things we don't realize about … pneumatic tires … is that air does 80% of the work in carrying the load," Nelson said. "It's very efficient and it's free, and it's lightweight — there are all these benefits to it.
"And so, when you take that out of the tire itself, you have to replace that with something. And so the materials are now doing the work."
That makes the structure of a non-pneumatic tire the single most important piece to puzzle out, the Bridgestone engineers said, because that structure has to support a lot of weight, manage road hazards and be both lightweight and sustainable.
And all of that makes its design — and especially its materials — critical.
Kimpel added: "First is getting to that stage of an efficient assembly that works. But then, longer term, how do we get to that and make sure the materials are recyclable?"
That is where Kimpel said he believes Bridgestone has an advantage, given the scope of the products it makes.
"You can categorize Bridgestone just as much as a material-science company as it is a tire company," Kimpel said.
So the non-pneumatic tire team is expanding beyond its tire expertise in its search for the best materials. It's an approach that Kimpel has encouraged, asking the team to seek the expertise of material scientists in aerospace and other industries.
"We have a lot of really strong, really great materials out there to choose from, but they are not that strong yet," Nelson said.
"We are at a unique moment in time where the materials and the technology are starting to come together to make this possible, but it's still at the cutting edge, the tip of the spear. So it's very challenging to make it all work together."
Kimpel contends there are several factors that have bolstered Bridgestone's bold approach, but one is making the greatest difference: advancements in tire modeling. The technology, he said, has allowed the Bridgestone team to test thousands of ideas without losing valuable time and resources.
Nelson agrees. The ability to test ideas and prototypes through extremely accurate and reliable simulation has progressed the nonpneumatic tire development significantly, he said. And that ability also completely changed the team's approach.
"We are changing how we design. We are being more meticulous with how we design," Nelson said.
"We are using our virtual tools in a way that we have never used before, and we are creating stronger technology every day."
So what, exactly, goes into the modeling that Bridgestone is leaning into? Well, just about everything.
"We're talking all of the elements in a tire, plus the full suspension on a truck, plus hitting objects on the roadway," Nelson said. "It is a large model, but one that the team has been able to develop in way that it runs quickly, it gives us reliable results, and coupling that with Amazon (Web Services), we are able to run thousands of iterations in weeks. And that is game-changing.
"Because before (that) we were running, you know, an iteration here and we're thinking about it, (and then running) an iteration there. And we would never have found the solution because you are just wandering in the dark so to speak.
"And now, we have the ability to map the whole space and we can say, 'Oh. That's where we need to be.' "
For Bridgestone, the significance of the modeling means it is not just changing the game for its Air Free tire development. It's changing the game for all of its tire development. Because some of the insights gleaned from the non-pneumatic tire simulations can apply across sectors.
"We have gone from a tire (iteration) that had a rolling resistance of 30 — and if you are familiar with tires at all, that is unheard of," Nelson said. "The tire would actually light on fire at that point, riding down the road. … Now we are at — potentially — industry-leading rolling resistance, even among pneumatic tires. So that's a feat. That's impressive."
So when will the technology be market ready?
Kimpel said Bridgestone is targeting 2025 for a "controlled launch" with the truck trailer tires with some selected fleet customers.
Bruce Davis, Tire Business staff, contributed to this piece.