Wheel rise, eventually, to classical Greece after the breaking of Minoan dominance and consolidations led by pre-classical Sparta and Athens. Celtic chariots introduced an iron rim around the wheel in the 1st millennium BCE. The spoked wheel was in continued use without major modification until the 1870s, when wire-spoked wheels and pneumatic tires were invented. The wire spokes are under tension, not compression, making it possible for the wheel to be both stiff and light. Early radially-spoked wire wheels gave rise to tangentially-spoked wire wheels, which were widely used on cars into the late 20th century. Cast alloy wheels are now
Wheel hub motor axles, provides a significant weight and manufacturing cost saving, while also decreasing the environmental impact of the product. The major disadvantage of a wheel hub motor is that the weight of the electric motor increases the unsprung weight, which adversely affects handling and ride. The wheels are more sluggish in responding to road conditions, especially fast motions over bumps, and transmit the bumps to the chassis instead of absorbing them. Most conventional electric motors include ferrous material composed of laminated electrical steel. This ferrous material contributes most of the weight of electric motors. To minimize this weight, several recent wheel-motor