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Bike Shop 3-5 / Week 05 / Thursday
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Week 05 · Gears and the Chain

Thursday

Gears for hills
// Counting teeth to predict turns
⏱ about 15 min

Thursday: Gears for Hills

Rocket races toward a steep hill. He pushes hard on the pedals. They barely move!

He hops off and walks his bike up.

Raven waits at the top. "What do you notice about your gear?"

Nova hovers by the back wheel. "Some gears make pedaling easier," she says. "Which back gear would you choose?"

Easy gears and fast gears

Gears let a rider pedal at a comfortable speed.

That works going uphill, downhill or into the wind.

For a steep hill, pick an easy gear.

The pedals turn many times to turn the wheel once.

On flat ground or downhill, pick a faster gear.

The wheel turns many times for each pedal turn.

Where you rideWhat the gear does
steep hillmany pedal turns for one wheel turn: easier pedaling
flat or downhillmany wheel turns for one pedal turn: farther each turn

A museum activity says to try this on a bike.

Put the chain on the smallest front gear and the largest back gear.

Then ask: is this setting better for a hill or a flat road?

PICK A GEAR
  • Read the question.
  • Tap your answer.
Rocket faces a steep hill. Which gear helps?
Raven rides on a flat path. Which gear goes farther each pedal turn?

Practice: which is easier?

Made-up practice numbers again. Each set has one front gear and one back gear.

Made-up setFront teethBack teethWheel turns per pedal turn
Hill set24241
Road set44114
Statement about the made-up setsTrue or false?
The hill set turns the wheel once per pedal turn.?
The road set turns the wheel 4 times per pedal turn.?
The road set is easier for a steep hill.?
WHY THIS EXERCISEThe hill set turns the wheel fewer times, so pedaling up is easier.
Rocket should have picked which made-up set for the hill? Type hill or road.
WHY THIS EXERCISEThe hill set makes the pedals easier to push on a steep hill.
Road set: 44 divided by 11 equals ____.
Hill set: 24 divided by 24 equals ____.
Try it
Pretend you are pedaling up a hill. Move your legs in small, easy circles.
Now pretend you are on a flat road. Each pretend push goes farther.
Which one felt easier?
Safety first
Do this sitting on a chair, not on a bike.
Real gear changes happen only with a grown-up, where they say to ride.
Helmet on for every ride.
In your shop notebook, sketch a bike on a hill. Label the gear you would pick.

Hill heroes! Tomorrow we learn how to look after the chain safely.

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