← Back to course
Bike Shop 3-5 / Week 05 / Friday
5/6
Week 05 · Gears and the Chain

Friday

Chain care
// Counting teeth to predict turns
⏱ about 15 min

Friday: Chain Care

Rocket rubs his finger on his bike chain. It comes away black and greasy!

"Oops," he grins. "Now I know why the rule says hands off."

Raven hands him soap. "What do you notice about your chain? Is it shiny or rusty?"

Nova hovers nearby. "A grown-up can turn the pedals while you watch," she says. "Look, but do not touch."

Look at the chain

A chain should not be caked with grease and dirt.

It also should not be dry and rusty.

To check it, someone holds the bike up by the seat.

A grown-up turns the pedals so you can watch the chain.

Does the chain skip anywhere? If so, tell a grown-up.

  • Look: is the chain clean or caked with dirt?
  • Look: is it dry and rusty?
  • Watch: does it skip while a grown-up turns the pedals?
  • Tell: report what you see to a grown-up.
Safety first
Hands stay far from the chain and gears whenever they turn.
A grown-up turns the pedals. You only watch.
A grown-up handles chain oil.
If you touch the chain, wash your hands with soap and water.
No bike? Look at a picture of a chain.
CHAIN CHECK
  • Read the question.
  • Tap your answer.
Who turns the pedals during a chain check?
What should you do after touching a chain?
You see the chain skip. What do you do?
Week checkTrue or false?
The chain carries the turning from the pedals to the back wheel.?
Front teeth divided by back teeth tells the wheel turns per pedal turn.?
A chain should be caked with dirt.?
Kids keep hands on the chain while it turns.?
WHY THIS EXERCISEThe chain carries the turning, teeth predict turns, and hands stay off.
The 54-tooth ring and 27-tooth cog turn the wheel ____ times.
Old high-wheel bikes had pedals on the ____ wheel.
SAFE CHAIN CHECK
  • ?A grown-up turns the pedals.
  • ?Someone holds the bike up by the seat.
  • ?Tell a grown-up what you saw.
  • ?Step back so your hands are clear.
  • ?Watch the chain go around.
WHY THIS EXERCISEHold, step back, turn, watch, then tell.
In your shop notebook, make a Hands Off the Chain sign for your bike shop.

Clean and careful work! Tomorrow is Bike Shop Day. You will count teeth with your family.

← Thursday