GR = T₂ / T₁
GR = Gear Ratio
T₁ = Teeth on driving gear (input)
T₂ = Teeth on driven gear (output)
Speed: ω_out = ω_in / GR
Torque: τ_out = τ_in × GR
Spur: Straight teeth, parallel shafts, simple design
Helical: Angled teeth, smoother operation, less noise
Bevel: Conical shape, intersecting shafts (typically 90°)
Worm: Screw-like driver, high reduction ratios, self-locking
Disclaimer
Gear ratio calculations are estimates. Actual performance may vary due to friction, backlash, and mechanical tolerances. Consult engineering references for precise design.
Gear ratio is the relationship between the number of teeth on two meshing gears. It determines how rotational speed and torque are transferred between the gears. When a smaller driving gear meshes with a larger driven gear, the output speed decreases while the torque increases proportionally. Conversely, when a larger gear drives a smaller one, speed increases while torque decreases.
Understanding gear ratios is essential in mechanical engineering, automotive design, robotics, and industrial machinery. Engineers use gear ratios to optimize power transmission, match motor speeds to load requirements, and achieve desired mechanical advantages in various applications.
Gear ratios are fundamental to countless mechanical systems. In automobiles, the transmission uses multiple gear ratios to provide optimal torque for acceleration and efficient cruising speeds. The differential gear allows wheels to rotate at different speeds during turns while maintaining power delivery.
In bicycles, the gear ratio between the chainring and sprocket determines pedaling effort versus speed. Industrial machinery uses gear trains to achieve precise speed reductions for heavy-duty applications. Robotics relies on gear ratios to convert high-speed motor outputs into slower, more powerful movements for actuators and joints.