If Toyota has its way, future electric cars from the company will run airless tires to help offset negative weight gains attributed to electric motors and accompanying battery packs.
Toyota chief engineer Takao Sato explained the conceptual airless tires to Bloomberg. They were first shown on the Fine-Comfort Ride concept unveiled at last week's 2017 Tokyo Motor Show and consist of a band of rubber encircling a plastic-aluminum hub.
Toyota Fine-Comfort Ride concept, 2017 Tokyo Motor Show
The chief engineer said future developments will likely help reduce the tires' overall weight. Right now, the airless tires weigh no less than a traditional air-filled tire. Specifically, Sato believes advances could shave 11 pounds per tire, which would mark a significant reduction compared to today's tires.
Weight reduction is important to ensure electric cars squeeze every mile worth of range from battery packs. The more weight the batteries and electric motors must power, the lower the overall range.
Sumitomo Rubber helped Toyota develop the airless tires, and the company says it's testing them on kei cars and golf carts in Japan. No company has carried out large-scale tests for regular passenger automobiles yet, though Sumitomo says the tire will work with any vehicle type.
Military vehicle equipped with Polaris Non-Pneumatic Tire
One challenge faced by Toyota and Sumitomo in the development of airless tires is dealing with rolling resistance. The airless tires' rolling resistance is about 10-20 percent worse than a typical modern tire, sapping the efficiency of the vehicle they are attached to.
Sato hopes advances will help make airless tires a better alternative to air-filled tires, though only expects them to be ready around 2025.
There is some good news. Sumitomo says the airless tires have already reached price parity with today's tires.