Both Pulley Diameter and Groove Design are crucial factors in the design of mechanical cable assemblies, cable assemblies, cable lanyards, custom cable assemblies, wire rope assemblies and pulley. Flexible cableconstructions are typically used in the design of pulley systems. Avoid using pulleys with smaller diameters than required, or the life of the cable will be reduced.


The Groove Design can be calculated by adding: 1.5 X Diameter Tolerance (including tolerance of bare cable or coating) plus the Maximum Cable Diameter.

Recommended Pulley Diameter to Cable Diameter ratios are listed below.


Pulley to Cable Ratio:

Results Represent Pulley Tread/Root Diameter TO Nominal Bare/Coated Cable Diameter

Preferred Minimum
Absolute Minimum


Pulley Construction:

Pulleys are most commonly made from aluminum, steel, nylon, and acetal. Some options to consider in the construction of pulley are sintered bronze bushings, an open or closed ball, or roller bearings. The corrosion resistance and RPM’s are also factors in the construction of a pulley system. Below is a chart describing some features and uses of common pulley and bearings.










Pulley Construction:

Plain metallic or Thermoplastic Pulleys
Metallic or Plastic Pulleys (Sintered bronze bearings)
Open free turning or precision closed (Lubricated ball bearings)

Lowest cost, light loads, low RPMSelf lubricated bearings, low cost durable, higher load,
shock resistance
Minimum friction,precise tracking, medium load, high
Common Uses
Low frequency drive and lift cable applications Medium RPM, load drive, index, and lift cable systemsHigh speed drive and index cable systems