Toyota Motor Corp is eyeing airless tires to help reduce the weight of battery-electric and fuel-cell vehicles and boost performance, even though the technology is years away from being ready for commercial use.<\/p>\n
The automaker is using airless tires – featuring individual motors in each wheel – on a vehicle for the first time with its hydrogen-powered concept car, Fine-Comfort Ride, unveiled at the Tokyo Motor Show\u00a0last week,\u00a0chief engineer Takao Sato said in an interview.<\/p>\n
Since such tires comprise a band of rubber encircling a plastic-aluminum hub, the premise is that they could one day compensate for the weight of the motors, he said.<\/p>\n
Currently the concept tires weigh about the same as their pneumatic cousins, but Sato is counting on developments in the technology that can help shave 5 kilograms (11 pounds) – or about 30% – from each tire\u2019s weight by as early as 2025.<\/p>\n
Sumitomo Rubber Industries, which supplied the tires and has been testing them on\u00a0local \u201ckei\u201d minicars and golf carts, said other Japanese carmakers are also interested, particularly for smaller electric vehicles.<\/p>\n
\u201cFor automakers, the attraction of airless tires is for electrified vehicles,\u201d Sato said. While Toyota\u2019s Fine-Comfort Ride is the size of a crossover SUV, \u201cthese wheels could be used on any electrified vehicle,\u201d he said.<\/p>\n
Wako Iwamura, head of the five-year airless-tire project at Sumitomo Rubber,\u00a0said his personal target is to have a commercial product ready by 2020.<\/p>\n
The Japanese tiremaker is actually a late entrant to the world of airless tires, following others including Bridgestone Corp. and Michelin & Cie Michelin\u2019s Tweel – a portmanteau of tire and wheel – is currently available for lawnmowers, golf carts, construction machinery, and recreational all-terrain vehicles.<\/p>\n
The technology is still unproven on passenger cars, and manufacturers will need to convince both automakers and the public that they are safe.<\/p>\n
A lighter tire is only one of Iwamura\u2019s goals. The other challenge to overcome is rolling resistance, or the friction that works against the tire when it\u2019s in motion.<\/p>\n
He estimates it\u2019s 10 percent to 20 percent worse than current pneumatic tires, a level unacceptable for vehicles that need to squeeze every kilometer of driving range from their lithium-ion batteries.<\/p>\n
Cost, however, won\u2019t be a hurdle. Iwamura says his tires are already comparable in price to those filled with air.<\/p>\n