Air does a lot for a traditional pneumatic tire. For starters, it helps support the tire in supporting the weight of your car. Air also helps absorb impacts, cushioning the tire (and your butt) over bumps. By varying how much air is in a tire, the pressure within the tire can be adjusted for a larger contact patch and more grip or a smaller patch that offers less rolling resistance and better fuel economy. But, air is obviously no good to a tire if it is not inside the tire—and even when it is, air is a volatile gas, meaning its pressure is susceptible to changes in temperature.
So, is there a better way when it comes to tires? A way that doesn't involve significant losses of air pressure (such as a puncture), or extreme variations of air pressure due to seasonal change (from summer to winter, for example) or temperature swings brought about by hard driving (increased road friction brings higher temps, meaning higher tire air pressures and thus changing contact patches and effects on braking distances, grip, fuel economy, and ride quality)? Sure—remove air from the tire's equation in the first place.
Bridgestone is doing just that with its airless non-pneumatic tires. The company's airless tires are composed of three pieces—the wheel, the "web," and the tread. The wheel is what you're probably most familiar with; it mounts to the axle. Fitted between the wheel and the rubber tread, another glossary term you're likely well-accustomed to, is the flexible web, which is what provides the compliance and cushion that pressurized air would in a standard tire. Bridgestone claims, by the way, that the tread is expected to deliver grip levels similar to conventional rolling stock.
Bridgestone is doing just that with its airless non-pneumatic tires. The company's airless tires are composed of three pieces—the wheel, the "web," and the tread. The wheel is what you're probably most familiar with; it mounts to the axle. Fitted between the wheel and the rubber tread, another glossary term you're likely well-accustomed to, is the flexible web, which is what provides the compliance and cushion that pressurized air would in a standard tire. Bridgestone claims, by the way, that the tread is expected to deliver grip levels similar to conventional rolling stock.
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The first time Bridgestone's airless tires will be put out into the world will be at the upcoming 2020 Tokyo games, where they'll be mounted to the 200 or so bicycles the tiremaker is supplying for Olympic staff and volunteers. Beyond this marketing exercise, Bridgestone is looking to supply fleet vehicles, namely long-haul trucks, with the tech. The company has developed an airless truck tire rated to support 5,000 pounds at speeds of up to 75 mph without overheating. (A comparable pneumatic tire would need to be inflated to 120 psi for the same duty cycle.) Apparently, the time saved by fleet managers no longer needing to check and maintain tire pressures—as well as spent repairing punctures and blowouts on the road—is significant.
The truck version of the special tires have a non-structural sidewall that covers the web that the tires on the bicycle do without. Jon Kimpel, Bridgestone's executive director of new mobility solution engineering, tells us the company's market research shows differing opinions on covering the web based on the application for the tire. We take that to mean some people might find the visible air space between the wheel and the airless tires' treads unsettling. Ironic, given how traditional pneumatic tires quite literally are supported by air.
Kimpel also told us that this is a sustainability play for Bridgestone, given that unlike pneumatic tires, the rubber tread can be replaced as it wears without worrying about whether it's airtight. They don't know yet about the service life of the wheel and web, though they say they're looking into how the components can be reused to maximize sustainability. Bridgestone has been eyeing airless tires for years, and it isn't the only tire manufacturer looking at the tech—Michelin has been toying with the idea, too.
