Rear gears on a bicycle

In the picture

1. 1The chain on a cog: its links fit the teeth and turn the rear wheel.
2. 2The spring-loaded arm: keeps the chain tight and swings to guide it.
3. 3The cable: pulls the arm when the shifter is clicked.
4. 4The stacked cogs: different sizes make the wheel turn faster or slower for each pedal turn.

Examples

• Clicking the shifter to make pedaling easier while riding up a hill.
• Clicking the shifter to go faster on a flat road.

Quiz: Rear gears on a bicycle (Age 11)

1. 1

   What does the derailleur do?

   • It locks the chain so it cannot move.
   • It makes the rear wheel spin without the pedals turning.
   • It moves the chain sideways onto a different rear cog.
2. 2

   What happens when the chain is on a larger rear cog?

   • The chain no longer turns the rear wheel.
   • The bike goes faster for each pedal turn.
   • Pedaling becomes easier.
3. 3

   When the shifter is clicked, what does the cable do?

   • It turns the stacked cogs by itself.
   • It pushes the chain directly onto a cog.
   • It pulls the spring-loaded arm.

The answers, each with its explanation, are in the app. This quiz is free there while the lesson is in the free week.