Like, on a mountainbike you have two levers, one for the index finger and one for the thumb. why does on the right side the index give a “harder” gear and on the left the index finger lever give a “easier” gear? couldn’t they both give high and low gear in the same direction?
In: Engineering
Your pedaling is translated to the rearwheel from the chainrings to the rear cogs via the chain.
Think of it like this. Suppose you have 36 teeth (t) in the front (this is the left hand), and 36t in the back (Right hand). For 1 pedal rotation in the front, the rear wheel spins once. If the rear cog is on 12t, for 1 rotation in front, the rear wheel spins 3x, which makes you go faster, but also requires considerably more effort. Now if you switch the front cogs to say, 48t, with 12t on the back, you’ll be rotating that rear wheel 4 times, instead of 3 previously
The thumb shifts to a larger size of ring for both the left and right-hand controls, but the effect that they have is the opposite due to the above reasons.
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