After the wheel rotates to a certain speed, the total air resistance produced by each wheel is relatively large, which can be greatly reduced after being radial. The single start of a highway soldier is integrated with the front spokes and the rear wheels because the rear wheels have to bear the torque generated by the driver's afterburner. This force is great, coming from two directions, one is the pedaling force of the driver, and the other is the lateral torque of the rear wheel when the driver "swings the car". Careful people will notice that every time the driver sprints at the end of the Tour de France, the rear wheel of the car sometimes moves laterally on the ground and bends left and right. Therefore, in the design of single start, in order to improve the rigidity of the wheel, making the rear wheel into an integrated one with greater strength than the radial wheel will definitely increase the weight, so making the front wheel without bearing such a large force into a radial one is only to reduce the air resistance. In triathlon, there are also such cars, of course, there are also bar wheels and front and rear spoke wheels, while track road races mostly adopt the integration of front and rear spokes and front and rear spokes.