How derailleurs shift while pedaling

Portrait-oriented cinematic movie poster, 1024x1536. A dramatic close-up of a road bike rear drivetrain in motion, with the chain moving across cassette sprockets, the rear derailleur cage and two jockey wheels clearly visible, glowing cable and housing pulling the mechanism inward. Split-lighting, deep shadows, crisp metal textures, motion blur on the spinning chain, vivid blue and amber highlights. Large, bold title text occupying the top 20 to 25 percent of the image, thick cinematic display font, high contrast and fully legible. The title is the only text in the image. No subtitles, no extra wording, clean composition, high detail, theatrical poster style.

The rear derailleur is the mechanism that shifts the chain at the rear sprockets, and it uses a cage with two pulleys: the lower tension pulley and the upper guide pulley.

Close-up of a silver bike derailleur on the back wheel of a dark grey road bike.

Photo of a silver rear derailleur against a white background.

Close-up of a rear bike derailleur being adjusted with a screwdriver.

As the rider turns the shifter, cable tension moves the derailleur linkage sideways, and the chain is guided onto a new sprocket while the return spring moves it back when the cable is released.

Close-up of a silver front derailleur on a matt black bike.

Smooth shifting comes from timing and light load: shift while pedaling, do it early before a hill, and ease the pressure if you must change under strain.

Cyclocross Bike

shifting

A grip shift shifter for a Pinion gearbox

An external drivetrain with a front and rear derailleur

Trigger shifters on a Specialized Sirrus commuter bike

A Shimano Alfine 11-speed hub with Gates Carbon Drive belt

How a Bicycle Derailleur Shifts in Motion

The rear derailleur is the mechanism that shifts the chain at the rear sprockets, and it uses a cage with two pulleys: the lower tension pulley and the upper guide pulley.
As the rider turns the shifter, cable tension moves the derailleur linkage sideways, and the chain is guided onto a new sprocket while the return spring moves it back when the cable is released.
Smooth shifting comes from timing and light load: shift while pedaling, do it early before a hill, and ease the pressure if you must change under strain.

How does a bicycle derailleur shift gears while you are still pedaling?. Show the chain path and jockey wheels, then visually explain how cable tension moves the derailleur to guide the chain onto a new sprocket. End by linking smooth shifting to timing and load, with a quick tip viewers can try on their next ride.

How A Rear Derailleur Works

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How derailleurs shift while pedaling

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