Compared with car, the bicycle is more popular as its features such as convenient, light and good for health. And it will not affect by the heavy traffic. Though it is a very common vehicle, you may not know very well about it. Generally speaking, the frame is the basic body for the structure of bicycle. Other components of bicycle are fixed on the frame directly and indirectly. The bicycle frames have various kinds of types, but they can still be divided as two kinds which are man's frame and woman's frame. The frame is usually welded and constituted by plain carbon copper tube. And some up-market bicycle will use low alloy steel pipe instead in order to reduce the weight of tubes and increase strength. Others also use streamline tube to reduce the resistance of fast driving. So we can find that the materials and size of frame will affect the bicycle performance. But what kind of frame can be considered as good one? In fact, the index like weight, strength and elasticity are the most important. Different manufacturers will use different technologies to reach such target. Such as whether the frame is designed according to the strength and features of materials? Whether the welding procedure is matured or not? These problems will affect the appearance, strength and elasticity directly. So when you choose a bicycle, you should pay attention on these factors. Besides, the painting is also important. The good painting is even and smooth. You can choose bicycle with three or four layers of painting to make sure your bicycle will not be rusty easily. Moreover, the derailleur is also essential part for bicycle. Many people think it is used for accelerating the speed, but the people can have 0.4 horsepower at most actually. The derailleur is just a too which can help people to give their power easily. Usually, the bicycle is used in urban, but there are still many inclined slopes in urban. At this moment, the effect of derailleur will become more obvious. If you have a derailleur, you just need to change lighter gear. Of course, it is also true in the teeth of the wind. Besides, the advantage of derailleur can help you when you are in good physical condition like cold. Since it is so useful for bicycle, you should pay more on this part. After all, the performance of bicycle is more important than appearance.