577503601 Lawn Mower Drive Belt 5/8" x 153" for Husqvarna MZ54 MZ5424S MZ5424SR 54-Inch Deck

What It Is

This is a replacement drive belt (5/8" wide x 153" long) for Husqvarna zero-turn mowers with a 54-inch deck. It transfers power from the engine to the transmission, so you can move forward and backward. It’s not the deck belt—this one drives the wheels.

Fitment & Compatibility

Check your model number first. This belt fits Husqvarna MZ54, MZ5424S, and MZ5424SR models specifically. It’s an OEM part (Husqvarna 577503601), so it matches the original belt dimensions exactly. Before buying:

• Measure your old belt: 5/8" width and 153" length are critical. A 1/2" or 152" belt won’t work.
• Verify your deck size is 54 inches. The same belt won’t fit 48" or 60" decks.
• Cross-reference with other brands (e.g., AYP, Poulan) only if they list 577503601 as compatible. Don’t assume.

Key Things to Know

• Quality: OEM construction means it’s reinforced for the high-torque, zero-turn stress. Cheaper aftermarket belts may stretch or snap sooner.
• Installation: Moderate difficulty. You’ll need to release tension from the spring-loaded idler pulley, route the belt around two pulleys, and re-tension. A diagram helps—take a photo before removing the old belt.
• Common gotcha: This belt drives the transmission, not the blades. If your mower won’t move but blades spin, this is likely the culprit. If blades won’t engage, you need the deck belt.
• Lifespan: Expect 300–500 hours of use with proper tension. Replace if you see fraying, glazing, or cracks.

Should You Buy It

If you own a Husqvarna MZ54, MZ5424S, or MZ5424SR and your mower has lost drive power, this OEM belt is the right fix. It’s a direct fit, durable, and worth the price to avoid premature failure. Skip it if you have a different deck size or a non-Husqvarna model.