The wheel is made into a circle and the characteristics of the circle are closely related, and the distance from the center of the circle to any point on the circle is equal.The wheel is circular. The axle is pressed on the center of the circle, and the wheel rolls on the ground. The distance between the axle and the ground is always the radius of the wheel. As long as the road is relatively flat, the vehicle will be more stable. .

The circle has a faster rolling force, and it is relatively stable to roll. If the wheel is round, the contact area with the ground will be greatly reduced, and it will be easier and faster to roll.If the wheel is square or triangular, the distance from the center of the wheel to the ground is constantly changing, and the vehicle cannot maintain stable driving on the ground.

In more science and technology museums, it can be seen that bicycles with square wheels on specially-made tracks pass by very smoothly without obvious bumps.As for why such wheels can also be square and so stable, this is because the track has been specially designed. This track is uneven, which just makes up for the inconsistency in the height between the center of the square wheel and the ground, so it will not be bumpy when driving.