The scheme of the transfer
Before adjusting the front derailleur on your bike, we recommend that you study its design. With this knowledge, it is much easier for the performer to navigate the settings and understand the purpose of each of them.
The focus is only on Shimano products, as the most popular. In fact, there are practically no differences between Japanese products and American SRAM. As well as between a cheap Tourney and an expensive Deore. over, if you delve into the principle of operation and the essence of the setting, then it will not matter to you which bike is in front of you: a budget Stealth with a Shimano Altus front shifter or an expensive Cube with a super-light Deore XT.
We will understand the device by the photo of the Alivio series switch:
- Inner and outer part of the guide frame. There is a chain between them. The function of the frame configuration is to move the chain from one chainring to another.
- A spring-loaded parallelogram to which a frame is attached. Moves when pulling / loosening the cable, dragging the frame structure with it.
- Cable fixing bolt. By means of a cable, the shifter moves the parallelogram.
- End position adjusting bolts (L and H). With their help, the border positions of the frame are adjusted so that the chain does not jump off the first and third stars.
- Clamp. Secures the seatpost to the center tube (into which the seatpost is inserted).
Why is the front derailleur rubbing against the chain
To understand what is the matter, one such symptom is not enough. Specify which gear it is in:
- Hits on the middle star. A skewed gear is in use or the cable is under-tightened / over-tightened.
- It only clings to the first asterisk. The frame limitation (bolt L) is incorrectly set, the chain is strongly skewed or the cable is overtightened.
- Rubbing on the biggest star. The border is poorly adjusted for large gears (bolt H), the chain is skewed or the cable is not tight.
For your information. The chain can touch the frame in any gear, if the edges of the frame are not parallel to the stars.
Why do not the front speed change when changing from 1st to 2nd or from 2nd to 3rd
For your information. Additional pull is pulling the cable in the current mode using the trigger on the shifter. For example, you switch the chain from the first chainring to the second by clicking the knob to the number “2”. The chain rubs against the frame, but does not go over to the adjacent toothed gear. Then you pull up the cable, slightly pushing the handle towards the inclusion of third gear, but not including it, and the chain freely goes to the star.
How To Adjust A Rear Derailleur | E-MTB Maintenance Skills
Unscrew the thumbscrew 1 turn and try shifting in place by lifting the rear wheel and pedaling. If the chain still does not move freely onto the large sprockets, turn the drum half a turn and try using the re-linking in place again. Repeat the ½ turn. check series until shifts in both directions are accurate.
For your information. The lamb’s stroke is limited to 5-6 turns. If this margin is not enough, then tighten the cable on the switch itself by unscrewing the cable securing bolt. Before clamping, turn the drum on the shifter until it stops, and then release it 1 turn. Repeat the thumbscrew adjustment procedure again.
Having achieved a clear transfer in place, drive and test the operation of the front block of speeds. Under load, the setting may not seem so ideal, so you have to turn the drum in one direction or another within ½ a turn and immediately check the new position while driving.
How to remove
Disconnecting the chain is indispensable here. We have already studied this procedure in detail in the material on how to change
the chain on a bicycle with shifted gears. If there is no lock, then squeezing is required. But in the future, we advise you not to give up such a convenient little thing as a chain lock.
It is advisable to wash the removed chain. It is important to choose the means, which we have mentioned more than once in the corresponding publication. Although the result of research on technology, how and how to clean a bicycle chain at home. impressed. We came to the conclusion that it is most convenient to do this with a high-pressure jet, and right on the bike.
- Disconnect the cable from it.
- Disconnect the frame fastening clamp.
Shimano Mountain Bike Front Derailleur Adjustment
First, use the Shimano Bike Reverse Speed Adjustment Guide. After all, a working rear dealer is one of the requirements of the preparatory measures. Among them there are also:
- Checking the cable and shirts. Fiber unraveling and sticking in the shirt is not allowed.
- Correct installation of the gear selection unit on the frame, described in the previous paragraph.
- Disconnected cable from derailleur.
The adjustment of the mechanism is carried out strictly in the stated sequence:
- Adjust the lower gear limiter. Switch to the smallest star in the front and the largest in the back (this will be 1-1 in the shifters). Turn screw L to bring the chain as close as possible to the inner edge of the frame. In this case, the chain should not rub against the frame structure. Take this step seriously if you don’t want the chain to come off and get bitten between the carriage and the small star.
- Connect the cable to the derailleur. Before attaching, screw in the thumbscrew on the shifter until it stops, and then turn it out 1-1.5 turns. At the final stage, this will facilitate readjustment.
- Adjust the upper gear limiter. Place the chains on the largest chainring at the front and the smallest chainring at the back (for example, on a 27-speed bike, this would be 3-9). Tighten screw H to move the outer edge of the frame as close as possible to the chain. Again, the chain should not rub against the transfer.
- Adjust the precision of the forward throw with the thumbscrew on the shifter. Everyone does it differently. One of the ways is to sit on the bike and, with the help of the drum, select such a cable tension force, at which the chain freely passes from the 1st to the 2nd star and from the 2nd to the 3rd. The second way is to put the bike in place, switch to the middle sprocket and alternately put the 2nd and the penultimate sprocket in the back. The chain should not rub in these positions. The extreme method does not differ in accuracy, requires verification on the move and is unfair for cheap class transfers.
For your information. When lubricating the cable, use only a special silicone lubricant that does not attract dust.
How to install
When securing the derailer on the frame, do not rush to tighten the clamp of its fastening. First, in the case of a thin-walled butted frame, overtightening will cause the seat tube to buckle. Secondly, the crossover has not yet been set relative to the stars.
Putting it right means fulfilling two requirements:
- The frame must be parallel to the stars.
- There should be a gap of about 2 mm between the teeth of the largest chainring and the frame structure, but not more than 3 mm.
Now tighten the clamp to a reasonable torque and install the chain.
Attention! Remember that frontal throws are different. Therefore, when choosing a new one, consider the following points:
- Number of teeth on each sprocket of the system.
- Traction type: top or bottom (determines the cable entry. from the bottom of the frame or from the top).