How To Choose A Bike Front Derailleur

Subtleties of operation

The gear shifter on a bicycle works precisely and for a long time if it is used correctly. To do this, you should read some recommendations. For example, switching between speeds should only be done while cycling. It is also recommended to reduce the pressure of the feet on the pedals when changing gears, especially this will facilitate the condition of the front derailleur.

Before going uphill, it is better to change gear in advance. This advice should be followed by beginners who still DO NOT know how to “feel” their transport. Also, do not shift multiple gears at once. The transition between gears should be carried out gradually so that the chain has time to jump to the previous sprocket.

It is important to learn how to avoid over-skewing the chain. This happens if you use both small or large chainrings and chainrings.

In you will learn how to choose a bicycle derailleur.

How to choose a rear derailleur for your bike. Speed ​​bikes

Where did the switches come from? The idea to form a transmission that is easy to control was realized at the beginning of the twentieth century, but the system was not very convenient. there were asterisks on each side of the rear wheel, and in order to “shift” the speed, it was necessary to literally transfer the chain from one sprocket to another.

Such a mechanism would remain the standard (in practice, it is also unused, since it was replaced by planetary models), IF it were not sports disciplines. In the 1950s, Italian Tullia Compagnoli invented and pioneered the modern rear derailleur.

How to choose a rear derailleur for your bike

First of all, it will be useful to answer the question: “Why are there gear selection mechanisms on a bicycle?” The fact is that the correct choice of gear allows you to vary the cadence (cadence) and the effort on them for the most efficient distribution of energy. This happens by changing the gear ratio between the pedals and the wheel. For example, when driving up a steep hill, you need to select a gear lower: in this case, the effort required to press the pedal will decrease, although the number of pedal revolutions required in order to drive up the hill will increase. If, on the contrary, you are driving down a steep mountain, then you must select the highest possible High gear, which will allow you to develop maximum speed. It was in order to change gears on the go that various types of switches were invented.

Service and customization

Derailleurs are some of the most subtle elements of a bike to adjust. Minimum Tolerances and Fatal Effects Incorrect settings on the chain and stars. all this dramatically increases the importance of correct tuning.

Since the travel is now standardized, cyclists have slightly less worries when setting up. Previously, it was also necessary to work with the tension of the cable. Now the main thing is to set the correct position of the extreme points of the switch.

This is done using bolts H (High, high position) and L (Low, low position). The chain is first thrown onto the largest chainring at the front and the smallest at the rear, and under constant observation, using the screw H, the bicycle derailleur is set so that the planes of the chainring, chain and derailleur frame become parallel. Then a similar adjustment is made for the second outer stars using the bolt L.

There are many obstacles that can interfere with the simple setting of switches, and that will require more serious intervention, which is already problematic to do it yourself.

  • Damage to any frame;
  • Set inconsistency While the capacity of the switch;
  • Damage to the frame or cock;
  • Inconsistency of the cable drive.

It is better to avoid these problems at the beginning of the setup.

Popular brands

The most popular brand currently is Shimano. This company is known for producing a wide variety of switches, ranging from the cheapest and ending with professional models. Many models from the manufacturer Shimano allow you to choose the best option for any bike: Road, city or mountain. For beginners, the “Sora” or “Tiagra” model is an excellent option.

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Among the popular manufacturers, Sram is worth noting. This company manufactures speed switches in different price segments. The main difference is the absence of thematic lines. Among the simplest and cheapest are the models “X-3” and “X-4”, and among the highest quality “X-7” and “X-9”.

Shimano’s main competitor in the near future is the Taiwanese manufacturer Microshift. The main feature of the company is good quality at low prices. Many European countries have already appreciated the speed switches of this company. It is worth noting that among the advantages of this brand there is another very important one. full compatibility with Shimano derailleurs. This plus can be used very profitably during repairs.

For lovers of the highest quality, pay attention to the German manufacturer Rohloff. Its planetary hubs are carefully selected and hand-assembled only. There are a lot of advantages in the products of this company, but it will be quite expensive to pay for them.

Construction and work

The principle of gear shifting is, in fact, very simple. Both devices are frames, which, being controlled through the drive cable by the shifter (shift knob), shift their position while on the system or on the rear hub, we move the bicycle chain with us.

At first glance, a trivial problem of complications by many factors:

  • High stress on the transmission. modern front and rear derailleurs place high demands on materials;
  • Positioning accuracy. small errors in the position of the frame (and, accordingly, the chain) can lead to rapid damage to the chain and stars by incorrect switching;
  • The subtlety of the mechanism. in a modern device there are more than two dozen elements, each of which must be almost ideally positioned and work under load.

Modern models are delicate mechanisms that require serious development and NOT less serious maintenance.

Let’s consider these devices in more detail. It should not be forgotten that both the rear and the front derailleur have their own restrictions on the types of attachment and dimensions that are allowed while in the transmission. The rear frames are also limited in overall length.

How To Choose A Bike Front Derailleur

Description and purpose

The greatest comfort while cycling and excellent energy saving is provided by a gearshift or derailer. With it, you can choose the optimal mode of travel, which is completely suitable for a specific route. The switch is especially useful if the track changes from asphalt to off-road.

You also have to use the device when accelerating, smoothly braking, climbing uphill. It is worth noting that thanks to the switch on the bike, you can maintain a constant speed, which is very convenient when overcoming long distances. Difficult weather conditions in the form of strong winds or slippery tracks are also easier to bear with the derailer. It’s no secret that a bike is an excellent cardio equipment, which is greatly facilitated by the speed switch.

Derailer, as we know it today, was invented in the 50s of the XX century by an Italian cyclist. The classic design is a block of stars. The unit, which is installed in the front, is called a system, and that at the back is called a cassette. The speeds are shifted by shifting the bike chain to the side, which in total allows the chain to lie on the selected sprocket.

All stars differ in diameter, and the chain has a fixed length. Thus, it sags, but this moment is removed by a special tension spring, which is located on the rear of the switch.

Typically, bicycles have 1 to 3 drive sprockets and 3 to 12 driven sprockets. This number creates over 30 speed combinations. Of course, some transmissions may be repeated.

The switches are controlled by cables. The tension of the cables can be adjusted using the shift knobs. There are shifters on the steering wheel, which pull the cable. When you press the shifter, the frame is displaced, and the chain is thrown to the adjacent star.

There is also an option where the switch looks like a drum, which simply rotates to the desired mark, indicating the speed. The bicycle derailleur can also be designed as a trigger or a combination handle. Recently, electronic control of gear shifting is gaining popularity, which allows you to shift through all the stars at once.

It is worth taking a closer look at how a traditional speed switch works. The system speeds are located on the left side of the rudder handle, and the cassettes are located on the right side. When shifting the chain from one chainring to another, it is important that the pedals rotate. Also, it is impossible in the process of switching between speeds, pedaling back, so that the chain does NOT jam, and the transmission does NOT break. It is worth noting that there is no rear derailleur on models with foot brakes.

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Modern manufacturers present different types of switches, which are designed for different types of cycling.

  • The external derailleur is the most common type, which consists of front and rear derailleurs. This option works by throwing the chain between the stars through the frame. The advantage of this switch is its lightness, clear design, and a large number of speeds. Also, energy is NOT lost due to friction of mechanisms inside.

However, it must be taken into account that such a switching system is subject to weather conditions. Over time, the chain will wear out due to strong distortion. Gears can only be changed while driving, and it is important to protect the bike from falling. Among the disadvantages, users also note the need for frequent maintenance.

  • The internal or planetary derailleur is a mechanism located in the inner part of the hub at the back. It has only one star in the back and front, and a chain. The number of speeds in such models starts from 3 Most bicycle models with planetary hubs are also equipped with an integrated brake system, which is very convenient.

Among the advantages should be highlighted High resistance to adverse weather and bad roads, High reliability, durability, ease of maintenance. Also important is the pedaling gear shifting. However, you should be aware that the internal switches have an impressive weight. In such models, there is excessive friction of the nodes, which leads to difficulty in movement. Among the minuses, it is worth noting the complexity of the repair.

  • Combined. a hybrid of planetary and external switches. Most often they are equipped with urban models of bicycles. This type is characterized by the pros and cons of both switching devices.

Choice and purchase

Although, as always, money is the main factor, there are a few technical characteristics to keep in mind when choosing a switch:

How much does a good switch cost? In fact. from 1.5 thousand rubles. Most riders absolutely do not need professional solutions with titanium elements and protection, with a huge road capacity or non-standard Shadow (construction is 30% smaller in width), which makes the model more expensive by two or three times. But if the price is not important, the choice changes dramatically. It is worth choosing only the best, choosing modern composites, accurately adjusting the capacity, so that not a single millimeter of sagging is allowed.

Choice and purchase

Although, as always, money is the main factor, there are a few technical characteristics to keep in mind when choosing a switch:

How much does a good switch cost? In fact. from 1.5 thousand rubles. Most riders absolutely do not need professional solutions with titanium elements and protection, with a huge road capacity or non-standard Shadow (construction is 30% smaller in width), which makes the model more expensive by two or three times. But if the price is not important, the choice changes dramatically. It is worth choosing only the best, choosing modern composites, accurately adjusting the capacity, so that not a single millimeter of sagging is allowed.

Gear ratio of the drive of the switch of speeds

Switch Drive Gear Ratio. the ratio of the switch movement to the corresponding cable movement. Shimano uses a 2: 1, 1: 1 ratio in its shifters and rear derailleurs, which is why THESE rear derailleurs are NOT interchangeable (although SRAM makes some shifters compatible with Shimano derailleurs). Although SRAM engineers claim that their 1: 1 system provides better performance in tough conditions and with cable contamination, there has been no practical evidence of this. And cyclists say SRAM’s derailleurs work harder than Shimano.

The situation is now even more complicated by the introduction of ten-speed drivetrains from Shimano and SRAM. Neither are compatible with 9-speed counterparts of the same firm, but SRAM’s 9-speed drivetrain is compatible with Shimano’s 10-speed Dyna-Sys mountain range. However, Shimano’s 10-speed road shifters and derailleurs are still designed for classic cable travel (2: 1), so there are naturally 10-speed ‘hybrid’ straight bar shifters that are compatible with classic derailleurs (R-series).

The principle of operation of the rear derailleur

The rear derailleur is a parallelogram mechanism with a powerful spring, which moves a frame (“foot”) with fixed rollers along the axis of the cassette. The speed selector is mounted on the cock with a hollow bolt and can swing up and down to maintain a constant distance from the idler roller to the cassette stars. Shifting gears in one direction is carried out by pulling a cable, hydraulic or electric drives. In the opposite direction, the switch moves under the tension of the chain passed through it.

Switching speeds is possible only when pedaling forward. When switching speeds, try to reduce the load on the pedals, although switching is possible and under heavy load this is undesirable, as it can lead to accelerated wear or damage to the parts of the switch.

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Service and customization

Derailleurs are some of the most subtle elements of a bike to adjust. Minimum Tolerances and Fatal Effects Incorrect settings on the chain and stars. all this dramatically increases the importance of correct tuning.

Since the travel is now standardized, cyclists have slightly less worries when setting up. Previously, it was also necessary to work with the tension of the cable. Now the main thing is to set the correct position of the extreme points of the switch.

This is done using bolts H (High, high position) and L (Low, low position). The chain is first thrown onto the largest chainring at the front and the smallest at the rear, and under constant observation, using the screw H, the bicycle derailleur is set so that the planes of the chainring, chain and derailleur frame become parallel. Then a similar adjustment is made for the second outer stars using the bolt L.

There are many obstacles that can interfere with the simple setting of switches, and that will require more serious intervention, which is already problematic to do it yourself.

  • Damage to any frame;
  • Set inconsistency While the capacity of the switch;
  • Damage to the frame or cock;
  • Inconsistency of the cable drive.

It is better to avoid these problems at the beginning of the setup.

Switch capacity

The capacitance of a switch is a value calculated as the sum of the ranges of view sets, i.e. Formula to calculate = (teeth on the large sprocket at the front. teeth on the small sprocket at the front) (teeth on the large sprocket at the back. teeth on the small sprocket at the back). After some simple calculations, a value appears in the range from 10 to 50, which can already be used when searching for the desired model.

Physically, this difference is in the length of the frame located between the two rollers of the rear derailleur, and the possibility of its deviation becomes determining in the delta of the sizes of the stars. Below, this indicator is strictly limited to a tolerance of 10 units.

Spring direction

The most common design of rear derailleurs (top normal), in which the chain is pulled on the large sprockets by a cable (by the force of the cyclist), and in the opposite direction the chain is pulled together by a spring. This is how all SRAM road derailleurs, derailleurs and most Shimano mountain derailleurs work.

In 2003, Shimano introduced an inverted rear derailleur (Rapid Rise or low normal). With this design, the cyclist, by means of a cable, drops the chain onto small stars, and on large ones it is tightened by a spring. The only plus of such a switch is that on a conventional shifter, smaller numbers correspond to smaller sprockets and the up / down gears on both shifters are the same. This can be convenient for beginners to learn. The main disadvantage is that this design has less dirt resistance.

Transmission: what are the best derailleurs on a mountain bike in various applications

The modern drivetrain layout, be it road or mountain bike, dates back to the mid-20th century. In the 1950s, the Italian Tullia Compagnoli invented a very convenient means of transferring the chain over the stars of the rear cassette. the rear derailer. Over time, the front.

Rollers

The bike’s rear derailleurs have two plastic rollers: a guide (upper) and a tensioner (lower). On some models of rear derailleurs, these rollers are not interchangeable with each other. There is also a difference between rollers from different manufacturers and different models of switches from the same manufacturer. The rollers are mounted on plain or rolling bearings and are consumables. They wear out faster than the switch itself, bearings loosen and teeth grind. In this case, they should be replaced with new ones, otherwise the clarity of the gear shift will disappear.

Determining which SRAM mountain bike derailleurs are better performing

The range of equipment is divided into 7 groups.

  • X3 / X4. Amateur grade identical to Shimano Altus / Acera respectively.
  • X5. In SRAM’s lineup, this group is marketed as Alivio in Shimano: equipment for advanced amateurs and avid cyclists. A distinctive feature is an excellent value for money. Follow instructions on how to adjust the rear derailleur. X5 owners will have to only a few times a season. the product retains the programmed settings for a long time, but works moderately in a dirty state.

When analyzing which derailleurs are better on a mountain bike, it’s worth keeping in mind that the top line in SRAM’s range of components is XX. This equipment is recognized as the best in the world. SRAM XX Components Fit Bikes Of World-Class Cycling Stars.