Cables and shifters let the rider to operate the gears. Cables are under constant tension and need to be replaced regularly and kept well lubricated. They must also be inspected often, and replaced if they show signs of wear. Shifters require only occasional lubrication of their inner workings.
How they work
An inner cable connects the gear-shift lever to the derailleur, and allows the cyclist to change gears. gears. Moving the gear-shift lever causes the front derailleur to shift the chain from one chainring to another. Pulling the gear cable shifts the chain from the smaller to larger chainring or cog; releasing the gear cable shifts the chain larger to smaller chainring or cog. cog. The left-hand shifter controls the front derailleur; the right-hand shifter controls the rear derailleur.
Cable clamp: Attaches the cable to the rear derailleur
Rear derailleur: Moves the chain from one cog to another
Front derailleur: Moves the chain from one chainring to another.
Cable: Connects the lever to the rear derailleur.
REAR DERAILLEUR CABLE
A clamp connects the cable to the rear derailleur. When the shifter is pushed, the cable pulls the rear derailleur inward, moving the chain from a smaller to a larger cog. When the shifter releases the cable tension, the springs on the rear derailleur pull the jockey pulleys, and the chain, back to a smaller cog.
SHIFTING GEAR
In this Campagnolo shifter, the rider pushes the inner shift lever to pull the cable and move the derailleur. When the rider presses a lever on the inner side of the lever hood, the cable is released and the derailleur moves back.
COMBINED BRAKE LEVER/GEAR-SHIFT LEVER MECHANISM
Gear-shift levers are often combined with the brake levers on the handlebar. On this Shimano shifter, the brake lever also acts as a shift lever. When the rider pushes the brake lever inward with the fingers, the control cable attached to it is pulled and a ratchet mechanism is lifted. One click of this mechanism equals one shift of the front or rear derailleur, which moves the chain across the chainring or cogs. The ratchet mechanism then holds the cable in its new position. When the rider pushes the inner shift lever inward, the ratchet mechanism’s hold is released and the pull on the cable ceases.