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A 12-tooth motor gear drives a 36-tooth wheel gear. Ideally, what happens to the output torque?

It triples, and the output speed drops to one third.

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  1. It triples, and speed drops to a third ✔
  2. It drops to a third, and speed triples
  3. Torque and speed both triple

Why: Gear ratio is output teeth over input teeth: 36 / 12 = 3. Torque is multiplied by the ratio and rotational speed divided by it. Gearing down trades speed for torque.

Huh, didn't know that: Real gears lose a little to friction, so the actual torque gain is slightly less than the ideal ratio.

The dad joke
I'm not slow, I'm geared for torque.
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References

Answer: It triples, and speed drops to a third. Gear ratio is output teeth over input teeth: 36 / 12 = 3. Torque is multiplied by the ratio and rotational speed divided by it. Gearing down trades speed for torque.

  1. Gear notes, CORC 3303, Brooklyn College CUNY www.sci.brooklyn.cuny.edu/~kammet/gear_notes.pdf
    The gear ratio is the ratio of the number of teeth on the output gear
    Checked 2026-10-10.
  2. Gear notes, CORC 3303, Brooklyn College CUNY www.sci.brooklyn.cuny.edu/~kammet/gear_notes.pdf
    if as a result of the gear arrangement the torque increases, the rotational speed decreases
    Checked 2026-10-10.

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