Skip links

Diameter Gauage


Our diameter gauge measures pulley diameter with unparalleled precision and provides a means to accurately predict fan airflow between pulleys in seconds. 

SKU: 667438785659


FPP -1 (Fixed Pitch Pulley Apparatus)

This model, FPP-1 is made specifically to measure the diameter of a pulley. It comes with a handy performance chart that is used to accurately navigate the airflow of a fan from one pulley to another in seconds. The diameter gauge is compact and unlike other measuring devices, it does not straddle a pulley to measure the diameter.

Changing Airflow is a Breeze – Example

Design Airflow = 4000 CFM

Present Airflow = 5000 CFM

Action (reduce) = 1000 CFM (reduce to 80% of 5000 CFM)

Pulley size = 6” (Diameter)


From intersection of 6” pulley, the red cell on the chart, scroll to the left along the 6” row until you get to desired target.  The closest you can get to 80% is 79% by using 4.75” pulley. 

  • No calculation or tachometer required.
  • It saves time, a lot of time

Technical information

  • Measures up to 11.5” diameter
  • The indices show the diameter of the pulleys most used in air movement
  • Packaged in a crash proof box.

Additional information

Weight 8 lbs
Dimensions 9 × 8 × 1.5 in


There are no reviews yet.

Be the first to review “Diameter Gauage”

Your email address will not be published. Required fields are marked *

Name *

Review *

This site uses Akismet to reduce spam. Learn how your comment data is processed.