A flat tire works on the principle of the relative movement between the surface and the wheel. This is different from conventional wheels, in that the flat driving surface of the round and the conventional tire. On a flat tire, the right wheel, while the surface of the trip is to wave like mountains and valleys.
We calculate the classic wheel mechanism. If the point of contact with the surface is a single wheel will continue to spin the wheel without for the moment, as a result of the rotational movement.
So why move the wheels when depressed, and was moved from its original position?.
Ultimately, the component from the rest of the contact point of the wheel and the surface, causing the forward movement of horizontal force. So that when pushed to a corner wheel speed caused two fixed horizontal and vertical components of force. Horizontal components cause forward movement, while the vertical component of the force causes the wheel rotates to handle. This may explain why the role of a cricket ball on a flat surface, with only small presses can go the path of 100 meters without stopping.
The area of the peaks and valleys, when force is applied to the fixed wheel, causing friction at rest in combination with the gravitational force of the wheels on curved surfaces. Style is such that the resulting speed in the same direction tends to peak or trough. When the power supplied is insufficient, the flat wheel can just sit in a saddle point. When the friction surface is curved, it can be provided that the movement of the flat ring on curved surfaces is equal to the wheel of the ball on a horizontal surface.
This allows periodic movements while a flat disk of curved surfaces. Yes, it is possible, when a curved surface is not wide enough and cause no net force on the locking ring and attack of the uneven surface.
Wheels of interest are a fixed point on the surface, as the weight evenly distributed on the circumference. Any bad side drop weight distribution produce waste of time and causing the wheels.