I read this [article](https://www.cycleworld.com/story/bikes/controlling-crankshaft-vibration/) like four times and I swear I know less now
In: Physics
Imagine a clock pendulum, it swings backwards and forwards at a fixed frequency. Gravity is always trying to return the pendulum to the centre. Now imagine the same pendulum without gravity – it wouldn’t work. But if you add a torsion spring at the pivot that tries to return the pendulum to the centre then it will work! The system of pendulum plus torsion spring will swing backwards and forwards (oscillate) at a fixed frequency. Change the stiffness of the spring (or the mass of the pendulum) and you will change the frequency.
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