About our Precision Variable Speed Pulleys

Speed range is variable within standard ratio limits.  Standard ratio, depending on pulley model is 2.45:1 and 2.8:1.  All of our variable speed pulleys are spring-loaded and color-coded to indicate spring pressure - easy to identify and use.

Standard bores range from 1/4" to 3/4" in both hex and round shaft designs. These pulleys combine the cost savings and strength of glass reinforced nylon and steel hubs with the wear resistance of steel-clad flanges.

Designed for belt sizes 1/4" V to 5/8" V and horsepower ratings from 1/12 HP to 1.0 HP.  They are engineered to offer an economical alternative for many applications that may not require the expense of AC/DC variable speed motors.

Torque Transmission Precision Variable Speed Pulleys

  • Economical
  • Lightweight
  • Strong
  • Quiet
  • Infinite speed range - within pulley ratio limits
  • Close tolerance on round shaft
  • Molded keyway on moveable flange

Contact us with your specific Variable Speed Pulley requirements >>

Standard sizes and types, detailed dimensions and spring pressures are listed below.

Precision Variable Speed Pulleys (VPSR) Engineering Specifications

Model Belt Speed
Ratio
HP Rating
@ 1800 RPM
Approx.
Pitch Dia.
Weight
VPSR-15 3/8" V Up to 2.45:1 1/4 1-3/8" Min
2-3/4" Max
5 oz.
VPSR-20 1/2" V Up to 2.8:1 1/2 1-7/16" Min
3-1/2" Max
8 oz.
VPSR-43 1/2" V Up to 2.8:1 3/4 1-21/32" Min
4.0" Max
1 lb. 11 oz.

 

Precision Variable Speed Pulley dimensions

Precision Variable Speed (VPSR) Pulleys Pulley Dimensions

Model A B C1
Open
C2
Closed
D
Dia.
Standard Bores
1/4 5/16 3/8 1/2 5/8 3/4
VPSR-15 2-5/8 9/16 3/4 7/16 2-7/8        
VPSR-20 3 5/8 7/8 1/2 3-1/2        
VPSR-43 4-1/4 25/32 1 1/2 4-1/4        
Non-Standard Bore sizes, both Inch and Metric are available upon request at no extra charge.  Please contact us


Precision Variable Speed Pulleys (VPSR) Spring Pressures

Model Spring Strength Color Code LBS. COMPRESSION IN SPRING
As Pulley Starts
to Open
Pulley
Fully Open

VPSR-15

Medium
Heavy
White
Blue
14
17-1/2
18-1/2
22

VPSR-20

Medium
Heavy
White
Blue
18
22
23
27-1/2

VPSR-43

Medium White 33
50
40
64

VPS Pulleys are shipped with the blue, heavy strength spring unless another strength spring is requested.

Download the Pulley Purchasing Checklist 

Precision Variable Speed Pulleys

Standard Tolerances for Bore Sizes, Keyways and Setscrews

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