How to install a gearshift mechanism on a bicycle

Chains and sprockets

represent a cassette. which consists of 6-7 stars. It all depends on the number of speeds on the bike.

And the chains vary in pitch and length. The chain pitch is the size of one link on the sprocket or chain, and in accordance with the pitch on the sprocket, you need to select the chain with the desired pitch. The length is basically the same everywhere, but it can also be of an individual size. Then you will have to look for it for a very long time, or rivet it yourself.

Steering wheel switches

There are two types of steering wheel switches. lever and cylindrical. Lever are a small lever located on the left or right of the steering wheel, with which the cable is pulled.

Cylindrical switches are switches that mount with a rubber or plastic handle to the edge of the handlebars. Switching here occurs by turning the handle down or up, then pulling the cable and moving the chain to the desired sprocket located at the back. They guarantee high-quality and fast shifting without getting off the bike and while driving.

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Cables and shirts

The cables for the front derailleur differ from the derailleur on the rear in that they can be slightly shorter, or even slightly thinner. And shirts are also divided into three types, and each shirt has its own cable.

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It must be said right off the bat that the hardest thing to tune is old, worn out switches. The cheapest spreaders made of low quality material wear out very quickly. After years of operation, so much material is produced in the joints of their mechanisms that backlashes are already becoming noticeable. Large wobbles of the rear derailleur will prevent you from adjusting to at least remove loud crackling when driving.

Adjusting the gearshift paddles is not a difficult job to be contacted by a mechanic. You will not be able to break the gearshift mechanism, the index system for changing speeds is the simplest and most reliable of all.

Rear derailleur cock

If, when the chain is on any one sprocket in front, the gear change from the rear is smooth, and when changing to another front sprocket, it becomes difficult to shift, then, most likely, the cock is bent on the bike.

The rear spreader, located down and away from the frame, is more prone to breakage than other parts of the bike when riding over logs or curbs. In the event of a fall, both the parallelogram switch itself and its mounting may bend from a side impact. If the rear parallelogram is attached directly to the frame, then it can break. If the switch is put on special fasteners, then it itself can remain intact, and the cock will bend, as a rule, towards the spokes.

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In order to determine if the cock is bent, and the rear derailleur at the same time, it is enough, sitting down behind the bike, to look at the position of the derailleur. Two rollers of the chain tensioner must be in a strictly vertical plane in relation to each other.

Under no circumstances should you try to straighten the bent cock by grabbing the rear derailleur. The spreader frame is very fragile. First, it is she who will begin to bend, and not the deformed fasteners. It is a good idea to completely remove the cock from the bike to align it on the plate. Better yet, use a special tool with which you can accurately straighten the bent mount directly on the bike frame. This tool works like a lever and has a pointer showing how accurately the cock is vertically aligned.

Chain tensioner rollers

The small sprockets on the switch frame should also be cleaned and lubricated at least once a year. Having outlived their own, and even without a share of attention, the rollers always jam, and the chain on them often simply rubs, bouncing and flying off the rear sprockets.

As for the material for making the rollers, that is, a carbon coating on top, and ceramic bearings inside. But to save the household budget, it makes no sense to buy expensive toys, since all common plastic wheels will last longer than the switch itself, of course, with simple maintenance.

Chain tensioner rollers

tensioners are part of a mechanism that provides high-quality chain tension during gear changes or while the bike itself is moving. Without it, the chain will not keep at the same level, which will not allow you to pedal or switch gears.

Installing the rear derailleur on a bicycle

Owners of an old bike equipped with a switch of an unknown brand always reach out to “bring it to mind”.

Often, with a device assembled independently from spare parts of various brands, many problems arise: from the constant throwing of the chain over the star to the complete “sabotage” of the movement.

Therefore, it is easier and cheaper to “get hold of” a new one, rather than trying to adjust and repair the rear derailleur on a bicycle, which is already hopelessly damaged.

For a bike that is used periodically and only on flat roads, it is impractical to install an expensive derailleur of famous brands (Shimano, Sram, and others). However, if you are planning to ride on hills and slides, pay attention to mechanisms with a large range of speeds.

How to install your Shifter and Rear Derailleur

Reverse derailleur setting

The principle of operation of the rear derailleurs is exactly the same as usual. Except for the direction in which the tension of its foot occurs. In this case, start the adjustment of the rear derailleur with the lightest gear (largest sprocket in the back), and all other procedures are the same.

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As you can see, adjusting the rear derailleur on a bike is not that difficult. The main thing is to understand its structure, have the necessary tools and read our instructions several times. And if you have any difficulties. feel free to contact us, we will show you how to be in your situation.

how to put a rear derailleur on a bike

The rear toggle switch is a parallelogram mechanism with a strong spring that moves a frame (“foot”) with fixed rollers along the axis of the cassette.

The speed toggle switch is installed on the “cock” with a hollow bolt and can swing up and down to maintain a constant distance from the guide roller to the cassette stars.

Gear shifting in one direction is carried out by means of tension of cable, hydraulic or electronic drives. In the reverse side, the toggle switch moves under the tension of the chain passed through it.

install, gearshift, mechanism, bicycle

Switching speeds can only be when pedaling forward. When changing speeds, try to reduce the load on the pedals, although shifting may be even under heavy load, this is not necessary, because it can lead to accelerated wear or damage to the parts of the toggle switch.

How to install a rear derailleur on a bike?

Rear Derailleur Setting Basics

In the event that you do not have sufficient experience in operating a bicycle and do not know how to adjust the rear derailleur on a bicycle, you will need to carefully study the instructions for your bike.

install, gearshift, mechanism, bicycle

Usually it is written in simple and understandable language, and you can figure it out without outside help.

If it is difficult for you to understand everything, you can contact the master who has sufficient experience in adjusting this unit.

The very same adjustment procedure must be started by checking that the roller designed for tensioning the chain is located exactly above the small sprocket.

If this position is not installed, it must be set using the adjusting screw marked with the letter “H” In order to move the roller to the left, you need to turn the screw clockwise, if you need to turn it to the right. counterclockwise.

Reaction to the rope

Many people have heard that derailleurs for bikes Shimano and SRAM. the leaders in the production of these devices. are not compatible. The reason for this is simple. different gear ratios are used in their products. If SRAM has 1: 1, i.e. when pulling the cable by 5 millimeters, the frame also shifts by 5 millimeters, while for Shimano it is 2: 1, i.e. when shifted by 5 millimeters of the cable, the frame will move by 10 millimeters.

So far, there is no sustainable proof of the advantages of a particular system, but versatility and interchangeability continues to suffer, including due to the emergence of new transmissions for 10-speed cassettes that do not work with the shifters of even their titular manufacturer.

Repair and installation

The switch may need to be repaired in several cases:

  • Rooster repair. if the damage was on it, and not on the switch itself. we dismantle and fix it.
  • If the rollers are loose or damaged.
  • When the frame was bent.
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Everything is corrected either by replacing the element (roller), or by straightening the bent parts, and sometimes by simply replacing the product. The most important thing is to correctly install the rear derailleur, our separate article is about this procedure.

Why is there a violation of gear shifting

To understand what action should be taken to adjust gear shifting, you need to understand what causes may lead to the problem in question. Experts identify several such predisposing factors:

  • deformation of the rooster;
  • stretching the cable;
  • deformation of the speed switch;
  • malfunctioning return spring.

Bicycle rear derailleur

Many bicycle lovers, while riding, gradually master the tuning and minor repairs of their bikes: here. tighten the brakes, there. change the saddle. But when it comes to the rear derailleur, a lot of people fail. Such a complex and not completely clear design raises more questions than answers, and portends difficulties not even in setting up, but in installing and removing.

Cable feed

Switches are rarely divided according to the cable entry point, but it should be understood how the shirt will fit in the event of a device change.

The standard approach is from the back, when the cable in the shirt makes a circle around the dropout, forming a small loop. In such a design, it is convenient to work with the cable, but the extra length of the cable and its bend lead to the need for more frequent maintenance and reduce the reliability.

An alternative is a straight line, where the cable enters the derailleur along the shortest path. Slightly more complicated cable and jacket operations are compensated by the greater reliability and security of the entire device. Originally only SRAM used this line, but in recent years Shimano and replica makers are increasingly switching to direct line.

Spring direction

The standard spring operation is when the chain is thrown onto the larger stars by force from the shifter, and to the smaller ones by the spring. This principle is universal, and so far the reverse device, when a smaller number on the derailleur corresponds to smaller stars, remains an experiment of Shimano, losing to the classics in resistance to dirt and damage.

Frame length

The length of the frame affects the capacity of the rear derailleur. This is the sum of the two differences. between the largest and smallest stars of the cassette and the system, i.e. the minimum required capacity for a combination of stars is calculated by the formula:

If the capacitance of the switch is less than the resulting value, the chain will sag at certain speed combinations. If you take the switch capacity with a serious excess, this will not affect the operation of the switching system, but the risk of damage will increase, since the frame will be longer, and the switch itself is larger and heavier.

The price, of course, directly depends on the length of the frame, which, in turn, with some exceptions, correlates with the “level” of the model.