Gilmer Belt Drive Crank Mandrel Pulley
Gilmer Crank Mandrel Pulleys
CMPG250 21 Tooth Shown

Gilmer Crank Mandrel Pulleys

For 1" Shaft and 1/2" Wide Belts
Part # CMPG Series
In stock - Usually ships in 1-2 Business Days
Starting at $54.00 ea
Features: Gilmer crank pulleys for 1" diameter crank mandrels with 1/8" keyway and with 1/2" wide Gilmer Belt. Features belt restraining lip built in with one piece billet design.
Qty Options:

No Slip Gilmer Belt Pulleys

These no-slip Gilmer Belt Pulleys are designed to be used with any 1" diameter Crank Mandrel that uses a 1/8" Keyway, which is a racing industry standard size. These are one piece pulleys and feature a built in lip to retain the belt if necessary. Two 1/4-20 Set Screws are included to lock pulley down on shaft.


All Gilmer Pulleys are designed for 1/2" wide belts and are designed to be used with our Gilmer Vacuum Pump Pulleys. However they may be used for other applications as well.

  • 14 Tooth Pulleys are often used with belt driven mechanical fuel pumps.
  • 14 Tooth Pulley OD is 1.67"
  • 21 Tooth Pulleys Medium Speed Crank Pulley for Vacuum Pump
  • 21 Tooth Pulley OD is approx. 2.5"
  • 28 Tooth Pulleys High Speed Crank Pulley for Vacuum Pump
  • 28 Tooth Pulley OD is approx. 3.5"

Pulley Ratio & RPM Calculator

GZ Motorsports Vacuum Pumps should avoid shaft RPM's in excess of 6000 RPM Pump Speed (not engine speed). The Formula used is Vacuum Pump RPM = Engine RPM x Crank Pulley Teeth/Vacuum Pump Pulley Teeth

Enter Engine RPM:  
Crank Pulley Teeth:  

Vacuum Pump Pulley Teeth  
Pulley Ratio %:  
Vacuum Pump Shaft RPM: