Gear shift on the bike: how to set up?

In our country you can meet a huge number of people who enjoy cycling. All modern models of bicycles are already equipped with a system of switching speeds. Such a mechanism is simply necessary for comfortable driving in any road conditions. Today, the transmissions for bicycles are of several types, and each is based on a certain work. To choose the most convenient option for yourself, you need to understand what they are, what makes it different and whether it is possible to customize the gear change on the bike.

Varieties of mechanisms

Regardless of the design features, each bicycle gearshift mechanism allows the cyclist to rationally distribute his efforts to rotate the pedals, considering both the force of pressing and the speed of rotation. Thanks to this, riding on the road with obstacles becomes as easy as on smooth asphalt. All the work of the transmission of bicycles is based on a change in the transmission ratio between the rotating wheels of the vehicle and its pedals.

This principle is common for all kinds of mechanisms, which can be represented as an external, internal or combined system.

The first option is found on pedal transport much more often than others. Its operation is based on the operation of two switches at the front and rear. To understand how a gear shift is performed on a bicycle, each of the mechanisms should be considered separately.

Front mechanism of external overturning

It is a construction with a moving frame inside that passes the chain through itself. Thus, when you switch gears on a bicycle, along with the movement of the frame itself, the chain also moves to the desired star.

The principle of operation of the mechanism is still not its only option in the selection, since such designs can also differ markedly from one another in such features as:

• Method of attachment to the body;
• Angle of attachment relative to the body of the bicycle;
• Option of fixing the cable.

The bicycle shift cable can enter the switch from above, from below. It is also possible to use both options. The second parameter should be selected with special attention to ensure the mechanism is as correct as possible, and the fastening of the structure itself can be done by clamps or carriages. In any case, the effective operation of the mechanism is provided only without a direct heavy load on it at the moment of switching.

Rear external switching mechanism

The work of this design is completely analogous to the foregoing front, with a difference only in a larger number of involved stars. It also has a moving frame that simultaneously provides the necessary tension of the chain and does not allow it to jump off in the other direction.

The given mechanism of a gear change of a bicycle also has certain parameters on which it is necessary to choose the suitable variant. Pay attention to:

• Type of attachment to the bicycle;
• Step of the shift cable;
• Difference in diameter of stars;
• Type of thrust.

It is interesting that the diameter of the largest star in this case will always be the same, and the choice of all these parameters should not be based on personal preference, but ideally suitable for a particular bicycle model.

Pros and cons of the external system

Among the positive aspects of the design in question, many emphasize simplicity, low cost, compact dimensions and at the same time a large number of switched gears. Of course, the disadvantages of external gear changes on the bike is not less.

These include:

• High probability of breakage during fall;
• Switching only when driving;
• Frequent chain wear;
• A high degree of influence of external factors on work.

Internal switching

This mechanism is rarely found on models for mountain driving, but is often applicable to urban bicycles. It is based on the work of the planetary bushing, which is located behind and contains inside the entire mechanism for switching. Thanks to this design, only one star in front and one behind, connected by a chain, can be seen on the exterior of the bicycle. The number of speeds of such a design is also quite large. In addition, the construction of the brake mechanism.

Advantages and disadvantages of the internal system

In comparison with the external design, this gear change on the bicycle can be carried out even when the pedal is completely stopped. Also, all the working parts are inside the bushing, which means they are protected from external factors, durable and reliable. The built-in brake and ease of operation should also be attributed to the advantages of the system, but there are also disadvantages. Among them, a large weight mechanism, the impossibility of self-repair on the road and the difficulty of movement in the friction of the nodes.

Combined system

Detailed description of it does not make sense, because such a mechanism has collected all the shortcomings from both of the above constructions. It can be met only on city bicycles, and it is a hybrid of a bushing and a conventional exterior structure.

Principle of operation of the mechanism

A bicycle model with the possibility of switching speeds is most often equipped with a pair of three stars ahead, called the leading ones, and several times with a large number of stars behind, called slaves. The front stars are arranged so that the smallest is closest to the body of the bicycle and is considered the first. The rear stars, on the other hand, are numbered from the largest, which is closest to the frame. Correct gear shifting on the bicycle must be carried out according to a certain scheme, which will not allow the chain to strongly skew, which leads to a quick breakdown of the whole mechanism.

So, for example, on a bicycle with three stars in front and nine behind, the switching will be as follows:

1. The front large star will be involved in the chain with the rear number 7, 8 or 9, provided the ride on a smooth track without obstacles.
2. The middle front star distributes the load together with the driven stars No. 4, 5 or 6 for driving along a country road, uneven asphalt, with wind in the face or with other obstacles.
3. The third leading star works in tandem with the rear stars 1, 2 or 3, creating comfortable driving conditions along difficult-to-reach roads, ascent and other heavy obstacles.

General conditions

To change gears on the bike was carried out as comfortably as possible, it is not enough to take into account the degree of patency of the road. The main criterion for choosing a transmission is the speed of the pedals, which should ideally be 80-110 revolutions per minute. Only at a given speed the ride will always be comfortable and not too tiring, so it's undesirable to start immediately with high speeds.

To extend the life of the transmission of your bike, remember that the main working star in front is the middle, because it does not allow a significant distortion of the chain while driving. Any throwing of the chain along the stars is completely controlled by the cyclist. In doing so, the correct pairing algorithm, described in the example above, must be observed.

The rules of cycling with the switching of speeds

First of all, this is a careful treatment of the whole mechanism. The chain should not be highly distorted during operation, and also have a minimum rotational load during the shift. In addition, any switching must be carried out gradually. It should not be "jumped" immediately from the first to the last gear, so before entering the mountain it is better to perform the switch beforehand.

Setting the mechanism

In fact, adjusting the gear shift on the bike is not too difficult for the cyclist and can easily be done on his own. The need for this procedure is the presence of problems during the gearshift, or in general the impossibility of switching the speed. In any case, you should start the work with the setting of the rear mechanism. Consider everything in order.

Rear Switch Setting

Before adjusting the gear shift on the bike, inspect the structure and ensure its integrity. Qualitative adjustment can be made only on condition that the chain tensioner is located strictly parallel to the cassette stars.

Setup begins with setting the chain in place for movement at the highest speed, that is, the smallest star. After this, the adjustment takes place by screwing the screws near the chain itself. The top should be screwed so that its shift roller is level with the small star, and the bottom screw should align the roller with the big star. Now you need to pull the shift cable for the bike and put it in the recess near the fixing bolt, which is then tightened. It remains only to check the quality of the work done by switching gears and dropping speeds. If the speeds are switched on badly, then the tension of the cable should be slightly weakened, but by another adjusting mechanism on the fastening of the cable. If the speed is poor, the cable should be tightened, on the contrary.

After all that has been done, it remains only to ensure the smoothness of the whole construction, which is done by installing the chain on a large star behind and a small one in front. With this arrangement of the parts of the mechanism, it is necessary to tighten the chain so that the upper roller is as close to the star as possible, but does not touch it. Similar work needs to be done by installing the chain in the opposite position - on a small star behind and on the big one in front. The degree of tension is regulated by a special screw, which is above all others.

Setting the front switch

Before setting the gear change on the bike, you should also check that the whole mechanism is correctly and securely attached to the bicycle frame. After this, it is necessary to set the minimum speed and loosen the cable, adjusting the distance between the frame and the chain by moving the right screw. The ideal gap is the distance of one millimeter, after reaching which the cable must be secured in a special groove near the bolt. Similar actions are carried out when setting the maximum speed, only by adjusting the left bolt. After all the manipulations, you need to test the work and, if necessary, loosen the cable tension. Such situations arise with poor switching to small stars. Otherwise, with a bad transition to large stars, the cable will need to be tightened more tightly.

Proceeding from all of the above, it is not difficult even for a beginner to perform an independent adjustment of the gear change on a bicycle, all the more so because the tools necessary for this are available for every cyclist.