Bicycle Rear Derailleur Adjustment

How to install a rear derailleur on a bike?

Having clocked many kilometers on a bicycle, I was convinced that a branded derailleur is much more important for a comfortable ride than stylish grips or leather Brooks. But it’s not enough just to buy Shimano or Sram, the quality of installation and setup is important.

A bit of boring theory

The rear derailleur mechanism throws the chain over the cassette stars, allowing you to lower or increase gears (for reference, it was invented by the Italian Tullio Campagnolo back in 1950). This device also keeps the chain taut. Since the invention, many varieties have been created. A little about the main, most characteristic features.

  • Manufacturing material. From steel to carbon. The entry-level models are equipped with steel, and not always of good quality, and plastic. In the right hands, these switches even work sometimes. Models of the middle category are in most cases made using aluminum. The most expensive models can boast not only precision in work, but also titanium, carbon or composite.
  • Frame size. In theory, everything is simple. the longer the frame, the more gears you can select. However, one cannot say so categorically, since someone will prefer a short frame that is not afraid of stones, while others are interested in greater comfort in switching. And everyone is right in their own way.

You can still describe in detail the action of the spring or the options for the location of the cable for a long time. However, many good articles have been written on this topic. I will only note that there is not much difference from which side the cable enters the switch. So, now about the interesting.

Installation and adjustment

Reference: The Shimano Tourney TX is the entry-level model, although the exterior design suggests a higher class.

And to put something more serious on an inexpensive bike used only for riding exclusively on asphalt. meaningless. Switching range was important, however, as the city is teeming with hills, hills and mountains.

So, replacing the rear derailleur begins with removing the old noname from the frame. it’s time for Shimano. The link of the chain is revealed. If this is not the case, then you need to use squeeze.

bicycle, rear, derailleur, adjustment

The old switch is unscrewed and removed, and a new one is hung in its place and screwed to the “cock”. protruding triangle with a hole in the frame. It is worth tightening well, but without undue enthusiasm.

We put the bike chain on the smallest star. Visually, the roller and small sprocket should be on the same line. The small star is the highest speed, therefore we adjust the position of the roller with the screw H.

Help: the letter H is an abbreviation for high gear, that is, top gear.

The next step is to insure against the possibility of the chain hitting the spokes, which is likely if the derailleur goes behind the largest sprocket. To do this, you need to move the switch to the largest star, carefully and without unnecessary effort. In no case by the roller, the mount of which is very easy to bend.

The adjusting screw fixes the position of the switch exactly so that it is opposite the large sprocket. Going behind it is fraught with the loss of knitting needles and good mood. If the switch is too tight, there will be no lower gear.

Queue for the cable. he should be free to wear a shirt. We check the progress and the absence of creases. On this switch model, you can see the place for the cable to pass. We put the chain on the smallest sprocket, tighten the cable to remove the slack, fix it. Thus, installing the rear derailleur and adjusting it are two integral, complementary processes.

Now check the operation of the entire mechanism. There should be no pronounced clicking sounds when pedaling from the rear derailleur side. Switching up / down must be accurate, without skipping and delays. And even if everything fell into place, it works accurately, quietly and without delay. for the first trip it is worth taking a screwdriver with you. Working with a load may well require minor adjustments.

Note that you will have to face such a concept as “preventive maintenance of the switch”, regardless of its price category. As the rollers, which are consumables, wear out, their timely replacement will be required.

It is believed that installing and adjusting the rear derailleur is much easier than the front derailleur. However, you will have to spend time and effort, but this work will pay off handsomely during the trip.

Front

The front derailleur is adjusted as follows:

  • Position the derailleur so that the rear is the largest star and the front is the smallest.
  • Unscrew the cable.
  • Adjust the position of the frame with the screw limiting the lower gears. It must be located a maximum of 3 mm further from the chain.
  • Stretch the cable a little.
  • Switch the speed to the middle of the stars.
  • Check if the chain is touching the outer frame or not. If the mechanism does not function properly after performing all the actions, tighten the cable even more.
  • Set the front derailleur to the smallest star.

At the end, it is important to check if the gear changes are easy. If the mechanism does not work, you need to adjust the screw that limits high gears.

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How to fine tune the rear derailleur

From time to time, bike owners have to fine tune the rear derailleur. As a rule, such work is carried out in the following cases:

  • repair, adjustment or complete replacement of chain drive elements was carried out;
  • new cables and their shirts were installed on the two-wheeled vehicle;
  • poor quality cables were installed on the bike and they constantly stretch during operation.

In this case, the switch is adjusted by unscrewing the hollow cable tension screw. it is enough to make a half-turn to the left. After setting, be sure to check the operation of the mechanism. ride a bike in different speed modes.

Using the tips and tricks given in the presented material, you can carry out the whole process yourself. The only thing to remember is that the rear derailleur, which is badly worn out, must be replaced: no adjustments / adjustments / replacement of the cables will help.

Steering wheel switches

If the shifter breaks on the handlebars, the cyclist will feel it right away. the cable tension instantly weakens, so it’s easy to “diagnose” the problem. In this case, the shifter must be replaced, but experienced cyclists do not recommend purchasing expensive components. with the correct operation of such parts, even not the highest quality will manifest itself only on the positive side.

Correct adjustment depending on the type

Adjustment is necessary in cases where shifting speeds on the bike starts to cause problems. As a rule, such actions are carried out in such cases:

  • a bike was purchased that was poorly adjusted in the sports department;
  • violation of the rules for transporting a bicycle;
  • vehicle mileage is large enough.

The work will need the following tools:

The front derailleur setting is significantly different from the rear derailleur setting.

Features and varieties

The Shimano product line includes a large number of derailleur categories depending on their purpose:

How to adjust the low gear limiter?

The function of the L limit screw is to prevent the chain from overshooting the large sprocket. Improper alignment can lead to chain seizure between the sprocket and spokes or the inability to engage low gear.

Before the adjustment procedure, you must install the chain so that it is on the back of the large sprocket, and in the front on the small sprocket. Screw L is removed as far as possible so that the switch can move without restrictions. The purpose of the setup is to align the tensioner rollers and large chainring in the same plane. The task is performed by rotating the screw L:

  • clockwise. the spreader assembly shifts towards the small sprocket;
  • counterclockwise. the node moves towards the wheel.

Preparation

First, place the chain on the middle sprocket at the front and the smallest sprocket at the back. Now we carefully inspect the rear spreader. it must be thoroughly cleaned of dirt, stuck blades of grass and sticks. The chain is washed and lubricated, the cassette is not only cleaned of dirt, but also blown out of dust. even these simple manipulations will lead to improved operation of the rear derailleur on the bike.

MTB Rear Derailleurs 101. Adjustment, Troubleshooting & Knowledge

The procedure for adjusting gear shifting on TM Shimano bicycles

All modern sports bikes are built with multi-speed bikes. In order for them to work fully, the system is equipped with special spreaders. True, they should be adjusted periodically. Special attention should be paid to the adjustment of the gearshift on the Shimano bicycle, which is popular with athletes. Difficulties with this will not arise if you carefully study the instructions.

Adjusting the chain tensioner

This process is simple and even an inexperienced cyclist, far from the principle of repairing his vehicle, will cope with it in a few minutes. What should be done:

  • The chain is translated to the smallest sprocket in the front and the largest in the back.
  • Pay attention to the rotation of the tensioner rollers. if at the time of the chain throwing it touches the star in the cassette, then you need to tighten the chain tension screw. By this action, a gap between the clinging elements of 5 mm is established.
  • The chain is rearranged to the largest sprocket in the front and the smallest at the back, along the way, the chain tension level is checked in this position.

How the switches work

Using the handle and shifter, the cyclist activates the required speed. In a certain position of the handle, the cable is pulled. As a result of this tension, the frame is thrown onto larger sprockets; when the cable is loosened, it is not thrown onto small sprockets. As mentioned above, you can start setting up your bike from the rear derailleur. Procedure for adjusting the rear derailleur:

  • select the second star in the front block, and the smallest in the rear one and set the switch chain on them;
  • The bike’s rear derailleur system has two bolts that act as stops. One is abbreviated as H, and on the other. L. These two bolts are used to adjust the high and low gears on the sprockets. If during the adjustment process any extraneous sounds arise, you can get rid of them with the help of the latch;
  • check the tension of the cable and if the tension does not correspond to the required one, use the regulator located on the shifter;
  • Test the switching quality. If the switching occurs smoothly, no extraneous sounds are heard, then you did everything right.
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Reasons for the deterioration of the rear derailleur:

Lack of service. Most often, when buying a bike, the derailleur works well and flawlessly, but after the season of operation, you can replace the deterioration in performance or even the chain jumping off the extreme sprockets. In 70% of cases, setting the rear derailleur helps, but sometimes this does not help either, then the cable and shirt should be replaced, as they become clogged with dirt and interfere with the smooth running of the cable in the shirt. Usually bike maintenance is done once a year, in which the switch settings are turned on.

Sometimes, to save money, they lubricate the cable with grease or any other lubricant and it turns out to improve the work for a while, but later the lubricant attracts dust to itself and the work deteriorates again, so you will have to do this procedure more often than you would like.

Deterioration of the switch itself. Everything ever breaks down and the derailleur on a bike is no exception. Most often, the parallelogram axes of the switch wear out, due to which a small backlash is formed, which does not allow the correct setting of the switch.

Derailleur sprockets are worn. Over time, plastic sprockets wear out due to which the chain no longer holds on to them, which leads to poor operation of the derailleur. Also, the sprocket axles can wear out and the sprocket will dangle unnecessarily on the axle, which leads to poor shifting.

Curve cock or the switch itself. When you fall or hit something with the switch, the cock will most often bend (break), since it is made specially from a weaker alloy than the switch itself (to keep the more expensive part intact). The curvature does not allow the chains to stand up exactly, which reduces the efforts to adjust the crossover to zero. Read how to straighten a cock with your hands.

Cable problems. Sometimes, during installation or when dropped, the cable may bend strongly, after which the place of the bend will prevent the smooth movement of the cable in the shirt. In this case, it needs to be replaced.

It also happens that the cable gets loose (that’s why you should use the ends of the cables) and subsequently one of the thin threads begins to separate from the main bundle, as a result, interferes with the normal movement of the cable in the shirt. Sometimes one thread in the cable can break and also prevent it from working normally, here you can isolate it from the main bundle along the entire length of the cable. But the best option would be to replace the cable with a new one.

If a new cable was installed, then sometimes after a certain number of kilometers (about 100 km), you can notice a deterioration in switching. this is due to the fact that the cable is slightly stretched. In this case, it will be necessary to tighten the cable tension bolt a little.

Important! If at least one of the 5 problems you have, it will not be possible to adjust the switch perfectly!

How To: Adjust Shimano Rear Derailleurs

How to fine tune the rear derailleur

From time to time, bike owners have to fine tune the rear derailleur. As a rule, such work is carried out in the following cases:

  • repair, adjustment or complete replacement of chain drive elements was carried out;
  • new cables and their shirts were installed on the two-wheeled vehicle;
  • poor quality cables were installed on the bike and they constantly stretch during operation.

In this case, the switch is adjusted by unscrewing the hollow cable tension screw. it is enough to make a half-turn to the left. After setting, be sure to check the operation of the mechanism. ride a bike in different speed modes.

Using the tips and tricks given in the presented material, you can carry out the whole process yourself. The only thing to remember is that the rear derailleur, which is badly worn out, must be replaced: no adjustments / adjustments / replacement of the cables will help.

Bicycle Rear Derailleur Adjustment

After we have eliminated all 5 possible problems with the rear derailleur, we can begin to configure it. I took a bike with a shimano rear derailleur and divided the whole setup into 8 steps:

On the shifter, we throw off to the highest speed (which corresponds to the smallest star on the block of led stars). We pedal so that the chain is on a small star. (now you understand why it is so convenient to work with the rack)

I do not show numbers on the shifter, but believe me the position of the indicator is on the “number” 9. Which corresponds to the smallest star on the cassette.

When adjusting the rear derailleur on the sprockets (front) the chain is best positioned where you use it most. This is usually the central star on a 3-star system.

Loosen the hexagon or bolt that holds the cable.

We twist it all the way, and then we return one turn back all the adjusting thumbs of the cable tension, which are located on the switch and on the shifter (sometimes there is only one adjustment screw on bicycles, most often it is on the switch, less often on the shifter).

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In my case, the cable tension regulator is located only on the shifter. The photo shows how I twist the lamb.

We pull the cable with our hand (it is not necessary to pull with all our strength, the main thing is that it does not sag and be stretched along its entire length) and tighten the bolt holding the cable.

Align the center of the derailleur foot rollers with the center of the smallest chainring on the bike. Some people remove the chain for stages 5 and 6 to fine tune them. I do not see the need for this, you can not shoot, especially if you have a switch that is not of the top level, such as shimano tourney, acera or alivio.

Actually, all this movement of the switch occurs using the adjusting screws with the letters “H” and “L”.

The shift pad position adjusting screws look something like this.

We turn the screw “H” with a screwdriver until the centers of the rollers on the foot of the switch and the small star coincide and go on to the next step.

In the photo, I showed a red line, by which you can see that the switch roller is under a small star on the cassette, which means that the extreme position is set correctly.

We switch on the shifter to the lowest speed (number 1), which corresponds to the largest driven star. We twist the pedals so that the chain goes to the extreme sprocket. And also align the center of the presser foot rollers with the center of the largest sprocket. All this alignment takes place with the screw “L”.

On the shifter, the indicator for switching the speed to number 1, if there are no numbers to the most extreme position, which should correspond to the largest star on the cassette.

Essentially, the “H” and “L” screws act as end stops for your derailleur, which keeps the chain from flying off while driving and keeps you alive.

We expose the extreme position of the switch foot so that the switch does not hit the spokes of the wheel. By aligning the axes of the largest sprocket on the cassette and the axis of the derailleur foot.

We drop again at the highest speed. Do not forget to pedal. The chain should be on the smallest star. Next, switch to one speed and turn the pedals, if the chain does not jump or does not jump right away, then you need to slightly unscrew the adjusting screw that adjusts the cable tension (it turns out we are pulling the cable).

Then again we check and switch from the highest speed one step lower (if an 8-speed cassette, then from 8 to 7 speed), if the switch happened immediately, congratulations you set the switch! You can check the remaining speeds will also easily and clearly switch both up and down.!

The chain should jump to the adjacent speed. In my case, this is a 9 speed cassette. Switching from 9 to 8.

Adjust the distance from the largest star to the derailleur roller. This distance should be about 4 mm, if the distance is greater, the switching clarity will be reduced. The adjusting screw on the switch is responsible for adjusting this gap. By unscrewing the screw, the distance decreases, screwing it in increases. tuning is done on the largest star corresponding to the number 1 on your shifter.

Release the cable

To do this, it is enough to screw in the tension screws on the rear spreader and on the handlebar near the shifter until they stop, and then pull the cable out of the clamping screw.

Experts do not recommend completely removing the released bicycle cable, but inspect it for damage (if they are found, the cable will have to be completely replaced) and thoroughly lubricate it, having previously cleaned it of dirt, it is imperative.

Bicycle Rear Derailleur Adjustment

Bicycle owners can always count on the help of specialized firms, which will carry out a full technical inspection of the transport, carry out repairs, and tighten / adjust / adjust everything. But in most cases, cyclists have neither the time nor the money to visit repair shops. in this case, recommendations, step-by-step instructions of the processes will maximally simplify the task of self-service of a two-wheeled vehicle.

Cyclists are often faced with the problem of adjusting the rear derailleur. Let’s make a reservation right away that it is very difficult to adjust old and worn-out switches. in some cases, the details of this mechanism are so worn out that even an inexperienced cyclist will pay attention to the existing backlash, which is almost impossible to get rid of. But on the other hand, if the rear derailleur on a bicycle has not yet passed into the category of “prehistoric”, then you can adjust it yourself. it is impossible to break the mechanism either theoretically or practically.