42 Inch Deck Belt 1/2" X 104" Made with Kevlar Replacement for John Deere GX20072 GY20570 L100 D100 110 120 130 L110 111 118 LA110 120 X105

What It Is

This is a 42-inch deck belt (1/2" wide, 104" long) reinforced with Kevlar, designed to drive the mower blades on select John Deere lawn tractors. It replaces OEM part numbers GX20072 and GY20570, commonly used on 100-series and L-series models.

Fitment & Compatibility

Before buying, confirm three things:

• Deck size: This belt fits 42-inch cutting decks only. Measure your deck width or check your mower’s model number.
• Model list: Compatible with John Deere L100, D100, 110, 120, 130, L110, 111, 118, LA110, 120, X105, and similar. Not for X300-series or larger decks.
• OEM cross-reference: Matches John Deere GX20072 and GY20570. If your mower uses a different OEM number (e.g., M156928), this won’t fit.
• Measure the old belt: Lay it flat and measure end-to-end. It must be exactly 104 inches. A 1/2" width is standard for these decks.

Key Things to Know

• Kevlar reinforcement adds durability over standard rubber belts, but it’s still an aftermarket part—quality can vary. Inspect for fraying after first few hours of use.
• Installation is moderate difficulty (30-45 minutes). You’ll need to remove the deck, route the belt around pulleys and tensioner, and reinstall. A diagram helps—take a photo before removing the old belt.
• Common gotcha: The tensioner spring must be fully released before routing. Forcing the belt on can damage pulleys or the belt itself.
• Break-in period: Expect slight stretching during the first mow. Recheck tension after 1-2 hours of use.

Should You Buy It

If you have a compatible 42-inch John Deere lawn tractor and need a budget-friendly replacement that’s tougher than a standard rubber belt, this is a solid choice. It’s not OEM, so don’t expect identical fit or lifespan, but for $16, it’s a good value for DIY homeowners. Skip it if you require exact OEM specs or have a different deck size.