Bike Gear Shift Adjustment Front Sprocket

How to set up and adjust the bike‘s front derailleur

Sooner or later, every cyclist has to adjust and tune the bike‘s front derailleur. And the cheaper the transfer, the more often. This happens for many reasons. For example, the cable is stretching, or you decide to adjust after replacing the derailleur. This does not change the essence. For this operation, you need to perform approximately the same steps. Therefore, we decided to talk in detail about how to set up and adjust the front derailleur of the bicycle using the example of pictures and videos, and what needs to be done before performing this procedure.

Design and principle of operation of the front crossover

The front derailleur design is very simple. We will consider all its components, as well as their purpose below.

  • Clamp. This part attaches the front derailleur to the bike frame.
  • Parallelogram. Parallelogram-shaped hinged spring-loaded part. It is the main moving part of the front bulkhead, to which the frame is attached.
  • A guide frame that has an outer and an inner part. A chain runs inside her.
  • Adjusting bolts L and H (stops). There are two of them. They restrict the movement of the guide frame towards the frame (L) and away from it (H).
  • Cable bolt. Locks the gear shift cable.

bike, gear, shift, adjustment

The principle of operation is based on a simple collision of the chain on the desired star. When the gear is shifted from a larger (in diameter) star to a smaller one, the cable tension is weakened, and the switch spring pulls the parallelogram with the guide frame a certain distance towards the frame. The outside of the frame pushes against the chain, causing it to bounce onto the smaller sprocket. When switching from a smaller star to a larger one, the opposite process occurs. The derailleur cable tightens and moves the parallelogram and guide frame away from the frame. The inner part of the frame presses on the chain, and thanks to the special shape of the frame itself, as well as special hooks on the sprockets of the front system, the chain engages and throws it onto a large sprocket.

This design provides limiting bolts (L and H) against which the parallelogram rests when the end positions are reached. If the setting of the front derailleur stops is not correct, the chain will jump off the carriage or connecting rod.

Adjusting and adjusting the front derailleur of the bike

After you have made all the preparatory measures, you can proceed to the adjustment and tuning. If you install a new derailleur or remove it during cleaning, then before adjusting it should be positioned relative to the chainrings, and then proceed with the adjustment.

Correct installation of the front derailleur

The correct position of the front derailleur is considered such that the longitudinal axis of its guide frame is parallel to the chainrings, and the distance from the bottom of its outer part to the largest chainring is no more than 2 mm. To make it easier to set the correct throwing position, it is advisable to remove the chain.

We set the distance from the bottom of the outer part of the frame to the largest star by moving the crossover along the vertical tube of the bicycle frame. We bend the parallelogram of the switch from the frame towards the largest sprocket, and, aligning the frame and the large sprocket relative to each other, we try to achieve the minimum distance (no more than 2 mm) at which its outer part does not touch the teeth. To simplify this procedure, you can insert some object between the frame and the parallelogram.

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If you bought a new derailleur from Shimano, then this procedure is simplified by the fact that there is a plastic sticker on the transfer frame with marks that indicates at what level it should be installed relative to the large star of the system.

After we have determined the height at which the switch clamp will be fixed, make a mark with a marker and slightly tighten the clamp fixing bolt.

To adjust the position of the frame axis relative to the star system, loosen the clamp bolt (while the cable should be folded back) and, by rotating the switch, adjust it so that the frame is parallel to the front sprockets. Due to the complex geometry of the latter, it is quite difficult to determine by eye. You can navigate by the parallelogram (if the design allows it). To simplify this operation, you can stick a ruler (on double-sided tape) or other object to the switch frame (on the double-sided tape) or other object that will simplify the positioning of the switch.

After that, slightly tighten the clamp bolt and re-check the distance from the lower edge of the frame to the largest sprocket in the system, and the parallelism of the longitudinal axis relative to the chainring.

If everything is fine, then completely tighten the clamp bolt.

This completes the adjustment of the position of the front derailleur. Now you can put on the chain and start setting up.

Why can’t I adjust the front derailleur

If you have not been able to clearly adjust the front derailleur of your bike several times, then most likely you have one of the following problems:.

  • Wrong switch or star system.
  • The switch is deformed or out of order.
  • Tight running of the cable in the shirt.
  • The shifter is out of order.
  • The chain is too stretched.
  • Derailleur, cable and chain are heavily soiled.

Speed ​​selector setting

In order not to keep the bike suspended while tuning, try hanging it from the saddle, thereby raising the rear wheel. You can also use an ironing board for this. We lay the bike with the upper tube of the frame on the ironing board plate, threading it into a triangle.

Setting up the front derailleur is straightforward. We will write it down point by point for greater clarity.

  • We set the lowest speed using the switch on the steering wheel (remember that at this stage the cable should not be attached to the crossover). We twist the adjustment of the tension of the gearshift cable on the shifter until it stops clockwise (if you look at the entrance of the shirt into the shifter) and return it back by 1-2 turns. Many recommend tightening completely, but as practice shows, for further fine tuning, it is better to leave a margin for tension / loosening of the cable in both directions.
  • Set the lowest speed on the rear derailleur (largest sprocket). As a result, you will get the first speed front and rear (the chain should be on these stars).
  • We adjust the limit switch L so that the inside of the frame is as close to the chain as possible, but does not touch it when pedaling. To do this, if you need to move the frame towards the bike frame, you should turn the bolt L counterclockwise, from the frame. clockwise.
  • We insert the cable into the place of fixation on the gear selector and, pulling it (with your hands, do not use pliers), tighten the cable bolt.
  • We switch gears from the front to the largest star, from the back to the smallest (the chain should be on these stars).
  • We adjust the limiter H. It is necessary to achieve such a position of the guide frame in which its outer part is as close as possible to the chain, but does not rub against it when pedaling. To move the frame towards the frame, turn the screw clockwise, in the opposite direction. counterclockwise.
  • We set the 5th speed on the rear cross-over. After that, turning the pedals, we change the speeds with the front switch over the entire range (3. 2. 1. 2. 3) several times. Then set speed 2 to the front and, shifting reverse gears, check that there is no friction between the chain and the frame in positions 2. 2 and 2. 7 (example for 24 speed bicycles). expensive front derailleurs can achieve frictionlessness even at 2-1 and 2-8 (although you should be aware that these are not normal modes and should not be used when driving). If there is friction of the chain against the frame in these positions or unclear gear shifting, then the cable tension should be adjusted by turning the adjustment on the front shift lever. In case of problems when switching from a smaller chainring to a larger one, tighten the cable (turn the adjustment counterclockwise), and when it is impossible to switch from a larger to a smaller one, loosen it (turn the adjustment clockwise). If there are no Комментарии и мнения владельцев on the work, then the next test must be performed under load when driving on roads.
  • We find a flat section of the road (without bumps and slopes) and check the operation of the front crossover while driving. In case of any problems when switching, right on the go, we rotate the adjustment on the shifter in the direction we need.
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If you do not understand something about how to set up the front derailleur, then we advise you to watch a video on this topic.

How to set up your bike‘s derailleurs

Every cyclist sooner or later faces the problem of poor gear shifting on a bicycle.

There may be several reasons for this. damaged cables or dirty shirts, a stretched chain, poorly tuned front or rear derailleurs. It is the latter circumstance that most critically affects the quality of gear shifting on a bicycle and can turn your ride into a continuous torment.

Many beginners rely on experienced mechanics for this procedure. This is the correct approach. But over time, you realize that you need to learn how to independently make the specified setting. This will not only help you save a certain amount of money on the services of a bicycle mechanic, but will allow you to independently, at any time, adjust the speeds, ensuring the perfect gear shifting of the bike throughout the entire trip. This text provides specific steps that even a beginner cyclist can follow to adjust the speed of his bike on his own.

Rear derailleur setting.

The first thing to start with the adjustment is an external examination of the rear overhang. It is necessary to make sure that the gearshift cable is securely fastened and supplied, its integrity, cleanliness and no wear of the upper and lower derailleur rollers. And also, the flatness of the foot, which during the operation of the bicycle can deform when falling.

It is very easy to check the foot evenness. you need to look at the rear of the derailleur and make sure that the corresponding cassette or ratchet sprocket, as well as the upper and lower roller of the derailleur, are on the same mowing line perpendicular to the ground. If all of the above conditions are met, you can safely proceed to setting.

It is necessary to set the chain to the minimum rear sprocket, correspondingly turning on the maximum reverse speed on the bike. To carry out the adjustment, both the front and rear cross-overs have two adjusting screws on their body, denoted by the letters H and L (High and Low, respectively). Since at the beginning of the adjustment, the chain was set to the maximum gear at the rear, for adjustment you need exactly the screw with the letter H, which is responsible for adjusting the high speeds. By rotating it clockwise or counterclockwise, they achieve such a position of the switch foot so that both of its rollers stand strictly on the same mowing line with the smallest back sprocket. After that, it is necessary to engage the minimum reverse gear, in which the chain is on the largest sprocket at the back. And with another screw, which is designated with the letter L, make an identical adjustment before aligning the rollers with a large sprocket.

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How To Adjust A Front Derailleur | Setup & Adjust Bike Gears

Sometimes a situation arises when, after correct and careful tuning and adjustment of the rear derailleur, a problem arises when shifting into high or low gears is poor. This is due to a strong or weak tension in the gear shift cable. This adjustment can be done in two ways. a special regulator on the rear derailleur, or a regulator on the gear shift knob (shifter). Which of the options is used on a particular bike depends on the level of equipment set by the manufacturer. If the chain is thrown poorly into lower gears, the tension of the cable should be increased, and if the chain is dropped to higher gears, on the contrary, it should be reduced.

There is another adjustment option on the middle and high level rear crossbars. distance of the idler roller (top) to the cassette stars (chain tensioner adjustment). It is produced as follows. The chain is installed on the largest sprocket at the back and the largest at the front. In this position, the rear derailleur foot will be pulled to the maximum. And with the adjusting screw, you need to achieve a distance of approximately 5mm from the top roller to the sprocket teeth. It is at this distance that the smoothest and most precise gear changes are made. It is not worth reducing it, as there may be a risk of grazing the roller by the sprocket teeth and damage it.

How To Adjust Your Front Derailleur

Front derailleur setting.

Before adjusting the front bumper, the first step is to make sure it is correctly positioned on the bike frame. For beginners, there are two recommendations. The first is to make sure that when the largest chainring is engaged in the front, its teeth are a short distance from the bend of the derailleur frame, as well as at the same distance from it. At the same time, in no case should they touch the frame or, on the contrary, be far from it.

The second is the parallelism of the switch frame to all the stars in the horizontal plane. That is, if you look at the switch from above, then its frame should be parallel to the stars of the system.

You need to start the adjustment by setting the chain to the minimum front and maximum rear sprocket. Next, you need to unscrew the bolt that fixes the cable to the switch housing. After that, it will take its natural position and you can proceed directly to the setting. Turning the screw marked L (Low) in different directions, you need to set the gap between the chain and the switch frame in the region of 1-2 mm. It is this distance that will ensure perfect shifting, and also eliminate the possibility of chain friction on the derailleur frame during driving. After that, it is necessary to fix the shift cable with a slight interference, making sure that it lies in the required groove in the clamping area. With the chain set to the maximum chainring and minimum sprocket, use the adjusting screw marked H to adjust the same way until the minimum clearance is found between the chain on the large chainring and the derailleur frame. If, after carrying out the above procedure, difficulties arise with the inclusion of low or high forward speeds, it is worth adjusting the tension of the shift cable, similar to setting the rear derailleur.

Having mastered both types of speed adjustment on a bicycle as quickly as possible, you will protect yourself from unpleasant surprises that may arise during the ride, having the opportunity to make the necessary adjustments at any time, spending a minimum of time and effort.