Enter the motor speed (RPM) and the gear drive output speed (RPM) into the Sheave Ratio Calculator. The calculator will evaluate and display the Sheave Ratio. 

Sheave Ratio Formula

The following formula is used to calculate the Sheave Ratio. 

  • Where SHR is the Sheave Ratio
  • MS is the motor speed (RPM) 
  • GS is the gear drive output speed (RPM) 

To calculate the sheave ratio, divide the motor speed by the gear drive output speed.

How to Calculate Sheave Ratio?

The following example problems outline how to calculate Sheave Ratio.

Example Problem #1:

  1. First, determine the motor speed (RPM).
    • The motor speed (RPM) is given as: 50.
  2. Next, determine the gear drive output speed (RPM).
    • The gear drive output speed (RPM) is provided as: 20.
  3. Finally, calculate the Sheave Ratio using the equation above: 


The values given above are inserted into the equation below and the solution is calculated:

SHR = 50 / 20 = 2.5

Example Problem #2: 

For this problem, the variables required are provided below:

motor speed (RPM) = 60

gear drive output speed (RPM) = 10

Test your knowledge using the equation and check your answer with the calculator above.

SHR = MS / GS = ?