They're designed to reduce the rolling resistance for electric vehicles, increasing range.

它们的设计目的是减少电动汽车的滚动阻力，增加行驶里程。

One good way to save fuel is to reduce rolling resistance, which is caused, in part, by a vehicle's weight repeatedly squashing its tyres.

节油的一个妙招便是减少滚动阻力，滚动阻力部分源于车辆对轮胎的持续挤压。