Transmission Flat Idler Pulley – Composite Nylon – Suits BigDog & Hustler Zero Turn Mowers – Replaces 604491

Description:

Non-Genuine BigDog and Hustler Transmission Flat Idler Pulley – Composite Nylon Construction.

Designed for selected BigDog and Hustler zero turn radius (ZTR) ride-on mowers ranging from 36″ to 54″ decks.

Lightweight yet durable nylon composite pulley ensures smooth belt operation, reduced friction, and long-lasting performance in high-speed transmission systems.

Direct replacement for OEM BigDog 604491 and Hustler 604491, ideal for maintaining drive efficiency and minimizing belt wear.

Replaces OEM:

BigDog: 604491

Hustler: 604491

Pulley Dimensions:
Specification Imperial Metric (mm)
Outside Diameter (A) 2″ 50.8 mm
Centre Hole / Bore (C) 3/8″ 9.525 mm
Material Composite Nylon —
Pulley Type Transmission Flat Idler —
Standard Pack Quantity 1 —
Fits Models:
BigDog Zero Turn Mowers

42″ Cut: Alpha (models 932897EX, 934489EX, 939140EX), Alpha MP (936393EX).

48″ Cut: Alpha MP (models 932947EX, 936526EX, 937581EX).

52″ Cut: Alpha Series (models 932913EX, 939124EX).

54″ Cut: Alpha MP (models 932939EX, 936518EX, 937573EX).

Hustler Zero Turn Mowers

36″ Cut: Raptor SD (models 935262EX, 938365EX).

42″ Cut: Raptor (models 933465EX, 934679EX, 938332EX, 939108EX), Raptor SD (models 935270EX, 936559EX, 938407EX).

48″ Cut: Raptor SD (models 932566EX, 936542EX, 938399EX).

52″ Cut: Raptor (models 931899EX, 938282EX, 939116EX).

54″ Cut: Raptor SD (models 932558EX, 936534EX, 938381EX).

Used as a transmission flat idler pulley on selected BigDog and Hustler ZTR ride-on models.

Features:

High-strength composite nylon provides corrosion resistance and lightweight performance.

Engineered for quiet operation and consistent belt alignment.

Direct-fit replacement for OEM pulleys.

Reduces belt vibration and extends transmission life.

Designed for high-speed transmission use on 36″–54″ deck zero turn mowers.

Specifications Summary:
Property Detail
Fits Brands BigDog, Hustler
Pulley Type Transmission Flat Idler
Material Composite Nylon
Diameter 2″ (50.8 mm)
Centre Hole 3/8″ (9.525 mm)
Standard Pack Quantity 1