42 inch Lawn Mower Deck Belt Compatible with John Deere Lawn Mower, Replaces Part Number GX20072 GY20570,Deck Drive Belt for L 100 130 1742 D100 D110 D120 D130 X110 X125 X145 E100 E110 E120 Series.

What It Is

This is a 42-inch deck drive belt for John Deere lawn tractors, transferring power from the engine pulley to the mower deck blades. It’s designed for residential/light-duty mowing on 42-inch cutting decks.

Fitment & Compatibility

Before buying, confirm your mower has a 42-inch deck and check your model number against the list: L100, L130, L1742, D100, D110, D120, D130, X110, X125, X145, E100, E110, E120 series. This belt replaces OEM part numbers GX20072 and GY20570. If your original belt has a different number, measure the old belt length (end-to-end, flat) – this belt is approximately 96.5 inches long and 1/2 inch wide. Verify your deck’s belt routing diagram (often under the seat or in the manual) matches a standard 42-inch John Deere routing.

Key Things to Know

• Quality: Aftermarket belt, not OEM. Reviews note it’s slightly thinner than genuine John Deere belts, which may reduce lifespan on heavy-use machines.
• Installation: Moderate difficulty – requires removing the deck or using a spring tool to release tension. Watch a routing video for your specific model.
• Common Gotchas: The belt may be tight on some decks; don’t force it – double-check routing. If your mower has a different deck size (e.g., 48-inch), this won’t fit.
• Warranty: No brand warranty listed; price reflects budget aftermarket quality.

Should You Buy It

This is a good budget option for occasional home use on a 42-inch John Deere, especially if you’re replacing a worn belt quickly. Skip it if you mow heavy grass frequently or want OEM durability – spend more on a genuine John Deere belt for longer life and exact fit.