Sumitomo Readies Airless Tire System

Japan’s Sumitomo Rubber Industries Ltd. is developing an airless tire system that the company aims to have production-ready by 2020.

The technology, which features a band of rubber around a plastic-aluminum hub, promises to reduce tire weight by as much as 30%, Automotive News reports. Automakers are evaluating such tires as a way to extend the driving range of electric vehicles.

Sumitomo, which has been testing airless tires on minicars and golf carts in Japan, outfitted the technology on Toyota Motor Corp.’s Fine-Comfort-Ride concept fuel cell car (pictured) that was unveiled at last week’s Tokyo auto show. Several other tiremakers also are developing airless tires—Michelin’s Tweel system is available on all-terrain vehicles, construction machinery and lawnmowers.

Sumitomo’s airless tires are cost competitive with traditional pneumatic units, Wako Iwamura, who heads Sumitomo’s airless-tire project, tells AN. But, he says, improvements need to be made to reduce rolling resistance, which currently is as much as 20% worse for an airless tire than a pneumatic one.

The airless tires used on Toyota’s fuel cell concept weigh the same as conventional units. But Toyota expects to realize an 11-lb reduction by 2025 as the technology continues to improve. The Fine-Comfort Ride crossover has an estimate driving range of 1,000 miles (629 miles), which is 50% greater than Toyota’s current Mirai fuel cell sedan. Most of the gain is attributed to an improved fuel cell stack.