The bicycle speed switch is designed to change the load required for a full wheel turn. In practice, the cyclist, changing the gear speed, changes the speed of the pedals. Each gear will be most effective for its type of terrain. The speed switch can be different (depending on the type of mechanism laid in its foundation). They are of the following types: mechanisms with external gear shifting, mechanisms with internal gear shifting, mixed mechanisms.
Cycle gearshift with internal gearshift
This type of switch is characterized by the fact that here, in contrast to the external one, the transmission mechanism is hidden in the rear hub, in which all actions to change the speeds are carried out. As a rule, with this type of mechanism, road and walking bikes are available today . Although sometimes this type of gear can be seen on the mountain "greats."
Due to the fact that the mechanism is closed by metal, its advantages are: wear resistance and durability, protection from bad weather and road conditions, an integrated brake, as well as ease of maintenance. The disadvantage of this type of mechanism is the understandable difficulty of repairing on the road when there is no special tool. Also, very intense friction of the nodes of the mechanism is not particularly pleasing. In addition, such a plan of the product is quite heavy, which increases the weight of your bike as a whole.
Speed shift bike with external gear shift
This is the most common option on modern bicycles (classic mechanism). It provides for two gear selectors at once: front and rear.
The front simply throws chains from star to star. This mechanism may also have a number of options that differ in the following things:
1) by the method of attachment to the frame (using a clamp or carriage clamp);
2) the angle of the installed switch relative to the frames may be different;
3) the drive cable can in different versions be attached to the mechanism (from the bottom or top side).
The rear gearshift has its own small feature. Firstly, it is here that the chain tension is ensured . Secondly, this switch focuses most of the bike speed options (the so-called sprockets). If there are only three stars on the front derailleur, then there can be up to nine of them in one cassette (on most modern bicycles).
As the positive aspects of the mixed system, the following is noted: low weight, a large number of gears, a budget price, simplicity of design, allowing independent repair. However, there are also disadvantages: low resistance to weather and road disasters, shorter duration in comparison with closed mechanisms.
Mixed Gear Cycle Speed Switch
This option combines a sleeve and a classic gear mechanism. However, the trouble with such switches is that their advantages hardly cover the shortcomings inherited from both types. For this reason, they are very rarely seen on the roads.