The transmission system generally consists of two parts: transmission components and shifting components. The transmission components include flywheel, bottom bracket, chainring and chain, and transmission components include transmission handle, front derailleur, rear derailleur and gear shift cable tube. The development of the transmission system did not happen overnight. After a long evolution, the ultimate experience of today was achieved. The early transmission not only had fewer options, but also was not easy to operate. However, with the development of technology, 12-speed and even electronic transmissions are gradually entering the market to meet the more exuberant needs of everyone. The picture below shows the new 12-speed electric transmission of Sulian released not long ago. With the variable speed system, the speed of riding is no longer solely dependent on the speed of pedaling, and the same cadence can be maintained by changing the gear ratio when encountering uphill.

1. Variable speed finger dial: the principle of variable speed, It is common before and after, and the principle is the same. All transmissions achieve shifting operation by stretching the bike shift cable.

The front gear is from 1 to 3 gears; the rear gear is from the largest gear to 1 gear, which is a forward gear. Back gear is to loosen the tensioned gear shift cable, the front derailleur and the back derailleur are flexible and will automatically return! So no matter whether it is shifting or retreating, as long as you master the strength of the transmission, you can successfully complete the shifting operation!

2. Variable speed front derailleur: H screw—used to adjust the position of the chain at the largest disc. Counterclockwise (spin out): the forearm arm is far away from the seat tube; clockwise (spin in): the forearm arm is close to the seat tube.

Note: The counterclockwise (screw out) must be mastered. Too much will cause the chain to fall off and get stuck between the crank and the big plate, which is very dangerous.

L screw-used to adjust the position of the chain at the smallest disc. Counterclockwise (spin out): the forearm is close to the seat tube; clockwise (spin in): the forearm is away from the seat tube.

Note: The scale must be mastered counterclockwise (screw out). Too much will cause the chain to fall off the plate and get stuck between the bottom bracket and the small plate, which is very dangerous.

3. Variable speed rear derailleur

H limit is used to adjust the positioning of the chain at minimum flight time. Counterclockwise (spin out): the rear arm is far away from the wheel set; clockwise (spin in): the rear arm is close to the wheel set.

L limit is used to adjust the positioning of the chain at maximum flight time. Counterclockwise (spin out): the rear arm is close to the wheel set; clockwise (spin in): the rear arm is far away from the wheel set. Note: When counterclockwise (screw out), you must master the scale, too much, it will cause the chain to fall off and be caught between the spokes and the flywheel, which is very dangerous.

Fine adjustment screw: counterclockwise (screw out): the rear arm is close to the wheel set; clockwise (screw in): the rear arm is far away from the wheel set. This is the line tension adjustment screw we often say. The tension adjustment is done by rotating that part counterclockwise and clockwise.

Before adjusting the gear shift cable, first check the limit position of the rear derailleur. In order to facilitate adjustment, the chain can be removed first, but it is not necessary. Loosen the gear shift cable and adjust the H limit screw first. This screw restricts the rear derailleur to the smallest flywheel position. Unless you are using the reverse pull rear derailleur, this is also the position where the rear derailleur maintains its natural state. Adjust this limit screw so that the upper guide wheel is located directly below the outer edge of the smallest flywheel.

Next, adjust the L limit screw. If you have already removed the chain, pull the rear derailleur back and push it under the largest sprocket. Try a few more times, and you can feel the rear derailleur hitting the limit screw. At this time, the rear derailleur should be located directly below the largest flywheel. If not, continue to adjust the L limit screw. If the chain is on the flywheel, you need to turn the crank by hand and shift to the minimum gear.

If there is a problem with the bike shift cable itself, it is not meaningful to adjust the rear derailleur. Therefore, check and lubricate the shifting cable before starting. The bike can be adjusted upside down, but it is best to hang the bike on the repair stand.

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