Scag Pulley, 4.00" Idler Part # 484128

What It Is

This is a genuine Scag 4.00" idler pulley (OEM part #484128) used to tension the belt and guide it around the deck spindle on select Scag zero-turn mowers. It’s a critical component for keeping the blade belt properly engaged and preventing slippage or premature wear.

Fitment & Compatibility

Before buying, confirm the following:

• Deck size & model: Fits Scag 48", 52", 61" decks on Cheetah, Turf Tiger, Wildcat, and Patriot models (check your specific deck serial number).
• OEM vs aftermarket: This is a genuine Scag part – aftermarket pulleys may vary in bearing quality and flange width, so stick with OEM for guaranteed fit.
• Measurements: The pulley has a 4.00" outer diameter (OD) with a 5/8" bore. Measure your old pulley’s OD and bore – if either differs, it won’t fit.
• Belt width: Designed for 1/2" or 5/8" wide belts – verify your belt’s width and that the pulley groove matches.

Key Things to Know

• Bearing quality: Genuine Scag pulleys use sealed bearings; cheap aftermarket ones often fail quickly due to dirt ingress.
• Installation difficulty: Easy – remove the old pulley bolt, swap the pulley, and torque to 25-35 ft-lbs. No special tools needed.
• Common gotcha: Check the idler arm bracket for wear or slop – a worn bracket will cause the new pulley to wobble and fail prematurely.
• Lubrication: Do not lubricate the pulley bearing – it’s sealed and grease will attract debris.

Should You Buy It

If you own a compatible Scag zero-turn and your current idler pulley is noisy, wobbling, or the belt is slipping, this is the correct OEM replacement. It’s a simple, affordable fix that restores proper belt tension and avoids deck damage. Skip it for non-Scag mowers or if you need a larger/smaller pulley size.