Gearing Up Ratio Task

  Gearing Up DLO:

Activity 1,  A. Look at the toothed cogs below. Each pair of cogs is joined by a chain. As the chain-ring cog in each pair turns one rotation, how many times does the free wheel cog turn? 

i: The free wheel cog will turn twice. 2:1

ii: The free wheel cog would turn three times. 3:1

iii: The free wheel cog will turn 4 times. 4:1

iv : The free wheel cog would turn 3 times. 3:1

B. Discuss with a classmate how you can work out the number of turns by using the number of sprockets on each cog?

We see how many times the number of free wheel cog sprockets fit into the chain-ring sprockets. 

Activity 2,  Look at the gears on a 10-speed or mountain bike.

How many different chain-ring cogs are connected to the crank? There is three chain - ring cogs connected to the crank. 

How many different free wheel cogs are on the free wheel cluster(at the rear hub)? There are 10 free wheel cogs connected to the free wheel cluster.

Activity 3. 

If you have a 10 speed or mountain bike you are allowed to ride, try changing the gears on it. 

What happens as you change gears? It would change onto a different cog and the bike would either have a stronger push or a weaker push.

              b.  How many different gears does the bicycle have? It has 10 gears. 

Activity 4 

In question 1, you found the ratio of each gear. The ratio of this gear is 30 :20 or 1.5 : 1. This is the number of turns the free wheel cog (and therefore the back wheel) makes as the chain - ring cog turns once ( 

and therefore, so do the pedals). 

Count the number of sprockets on each chain-ring and free wheel cog of your bike. Use this information to work out the gear ratios. About 47.

Which gear ratios are best for climbing hills? Why? 

2:1, because the faster you pedal the cog will turn faster and you will be able to get up the hill. 

Which gear ratios are best for cycling fast? Why? 

10:1 because the higher the gear the longer you pedal but you have more push so you go faster.