Gear ratio
Also: reduction ratio
The ratio that trades rotational speed for torque between input and output.
For reduction G = ω_in/ω_out; ideal torque multiplies by G while real output includes efficiency and load-dependent losses.
- Formula
G = ω_in/ω_out; τ_out ≈ ηGτ_in
Example A 4:1 ideal reduction gives one-quarter speed and four times torque.
Common misconception Gearing does not multiply power or guarantee the motor can operate at stall continuously.