Large and Small Diameter Lifting Pulley / Drums Equation and Calculator
Mechanics and Machines Calculations Menu
A simple pulley and drum may be used to lift a weight by applying a force with a rope which is wrapped about he outer diameter of one of the diameters.
F : W = r : R 
W = (F x R)/r 

F x R = W x r 
R = (W x r)/F 

F = (F x R)/R 
r = (F x R)/W 
Where:
W = Unknown weight (lbs, N)
F = Applied force (lbs, N)
R = Radius large diameter (in, mm)
r = Radius small diameter (in, mm)