What's the difference between an ordinary bicycle and a speed changing bicycle?
A variable speed bicycle can adjust the tooth number ratio, when the slope or uneven road, can be adjusted to ride more effort (such as applied to mountain bike, the wheel disc to a minimum, the larger gear disc, the flywheel can climb the tower to the steep slope);
A speed change system has been added. The ratio of the teeth of the ordinary bicycle to the flywheel is fixed (that is, the number of turns is fixed after one turn)
If the road is very smooth or meet the downhill, want to have very fast speed, can be said that the number of teeth in turn, kick a circle can go far, and ordinary cars to achieve higher speed can only rely on increased tic frequency, to a certain high frequency when the leg is difficult to adhere to, and easy removal of the foot (the foot slipped from the pedal), is dangerous. So the general car often according to the specific terrain need transmission system configuration match, make riding can well adapt to various locations.
