Crank Pulley Gilmer 21T

The Crank Pulley Gilmer 21T by Peterson Fluid Systems is a precision serpentine pulley system designed for engine builders and automotive enthusiasts who demand reliable belt drive efficiency in high-performance applications. This compact component replaces factory pulleys on modified engines running aftermarket superchargers, alternators, or custom accessory drives where Gilmer (HTD) belt profiles are specified.

Weighing just 0.34 pounds, it integrates seamlessly into tight engine bays while maintaining the critical load distribution required for accessory drive longevity. The 21-tooth Gilmer profile teeth ensure positive belt engagement without slippage—essential when driving high-parasitic-load accessories like centrifugal superchargers or large displacement alternators that would spin out conventional V-belt systems. Peterson Fluid Systems pulleys are manufactured to tight tolerances, minimizing radial runout that causes vibration and premature belt wear.

The compact outer diameter of 3.8 inches allows installation in congested underhood spaces common in engine swaps and tight-fit builds, while its 1.3-inch width accommodates standard Gilmer belt widths used in motorsports and marine applications. This pulley suits builders upgrading small-block and mid-sized engine packages running custom serpentine systems where OEM harmonic balancers won't accept Gilmer profiles. Verify pulley bore size and keyway specifications against your crankshaft before ordering, as Peterson Fluid Systems produces multiple variations.