A next-generation Chevrolet could have airless tires

By Peter Valdes-Dapena, CNN Business

Michelin has been working with General Motors to develop airless tires that will be sold on a next-generation Chevrolet Bolt electric car, expected to go on sale in the next few years, a Michelin executive said. It could mark the decline of over 130 years of tire tradition but also the end of one of the most annoying aspects of car ownership: keeping air in the tires.

“We want to bring the next generation of the Chevrolet Bolt with airless tires,” Alexis Garcin, president of Michelin North America said in an interview with CNN Business, “and it’s going to happen now in the next three to five years.”

GM has not confirmed that it is working on a new car to be called the Chevrolet Bolt, the same name as the automaker’s current EV, but GM has said it is working on a wide variety of electric vehicles including affordable ones similar to the Bolt in price. Michelin and GM have tested the airless tire on current-generation Bolt cars, though, something the companies have been open about.

It’s ironic that the first airless tire for passenger cars might come from the French tire maker whose famous mascot — Bibendum, more popularly known as the Michelin Man — is made from air-filled tires. The company made its name in the late 1800s with advancements to pneumatic (air-filled) tires for bicycles and was among the first to produce and market them for use on automobiles. In 1899, the first car to set a world speed record using pneumatic tires, a rocket-shaped electric car that went 66 miles an hour, did it on Michelins. The company has gone on to produce pneumatic tires used in other speed record attempts by companies like Bugatti.

The disadvantages of filling tires with pressurized air are obvious. Air is a gas that can leak, and tires are vulnerable to punctures. Tire makers have spent over a century coming up with ways to minimize punctures and keep air inside these circular rubber tubes, but it still happens with some regularity.

Michelin’s airless tire design relies on flexible ribs to provide a sort of spring action, roughly the same way air does in a pneumatic tire. If the tread gets punctured, it makes little difference since the tire doesn’t hold in air. In fact, the sides of the airless tire are completely open.

Of course, there are reasons airless tires haven’t been used on passenger cars in over a century. Air does have its advantages. For one thing, pressurized air allows tires to be customized for specific uses. For instance, a driver taking a four-wheel-drive truck off-road might reduce the air pressure in the tires, which allows the tire to flatten out a bit creating a larger footprint area on loose sand or dirt. The tires can then be re-inflated when the truck goes back to driving on asphalt.

Also, car companies have been engineering cars and their suspension systems for a century with the idea that the vehicles would be riding on air-inflated tires. Airless tires could perform differently, presenting a challenge for car engineers.

Michelin is trying to replicate as closely as possible the behavior of air-filled tires. Given the completely different structure of these tires compared to pneumatic ones it will be challenging to replicate that feel, said Ryan Pszczolkowski, who oversees tire testing at Consumer Reports. It’s especially challenging given that pneumatic tires come in a wide variety and feel and behave differently from one another.

“I mean, we’re literally reinventing the wheel here,” he said.

Michelin already sells an airless tire, called the X Tweel, for use on lawnmowers and similar off-road equipment like ATVs. One X Tweel for a lawnmower — it includes the tire and its integrated wheel, rather than the tire and wheel being separate — can cost over $600, according the product website. But Michelin claims they last longer than pneumatic tires and offer a more a comfortable ride because they aren’t as bouncy.

But passenger car drivers are going to be pickier than lawnmower drivers about things like ride, handling and noise. Cars operate at much higher speeds and take corners much faster than off-road machinery. Michelin engineers have to replicate the feel and performance of pneumatic tires under this more demanding daily use.

For these reasons, the passenger car version Michelin is developing, called the Uptis, has a different construction even though it looks almost the same as the X Tweel. The central ribs that hold it up are made from rubber reinforced with resin-injected fiberglass while the X Tweel’s ribs are made with polyurethane, for instance.

Garcin also envisions the tire incorporating other technological advancements. It will be completely recyclable and renewable — it will easy to retread and reuse — and it will have real-time connectivity so drivers will be able to easily monitor tread wear.

Of course, any consumer acceptance of an airless tire will also depend on the cost. But its introduction on a next generation of Bolt, a car that starts just shy of $32,000, appears to indicate that airless tires won’t be limited to the upper end of the market

Beyond this first electric car, the sheer variety of tire sizes and types already on the market will create its own challenges, said Pszczolkowski, as Michelin works to create airless tires for more vehicles.

“It seems like every time a new vehicle comes out a new tire size is invented,” he said. “It’s really maddening.”

In the end, said Pszczolkowski, the success of airless tires really depends on how much trouble and expense consumers are willing to go to to avoid a flat tire.

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