GX20072 GY20570 Deck Belt 42 inch Deck for John Deere D100, D105, D110, D120, D130, LA115, L100, L108, L110, L111, L118, L130 Lawn Tractor Mower 1/2" x 104"

What It Is

This is a replacement deck belt (1/2" x 104") for 42-inch cutting decks on select John Deere lawn tractors. It drives the mower blades from the engine pulley and is a direct fit for models like the D100, D105, D110, D120, D130, LA115, L100, L108, L110, L111, L118, and L130.

Fitment & Compatibility

Before buying, confirm your deck width is exactly 42 inches (measure blade tip to blade tip). This belt replaces OEM part numbers GX20072 and GY20570 – check your owner’s manual or old belt for these numbers. It fits John Deere 100 and LA100 series tractors listed above, but not models with 48-inch or 54-inch decks. The belt is aftermarket, not OEM, so verify the length (104 inches) and width (1/2 inch) match your original. Inspect your pulleys for damage or wear before installation – a worn pulley can cause a new belt to fail quickly.

Key Things to Know

• Quality: At $13.97, this is a budget aftermarket belt. It’s generally reliable for residential use, but may not last as long as an OEM belt under heavy or frequent mowing.
• Installation: Moderate difficulty – requires removing the deck or working underneath. You’ll need a wrench to release belt tension. Watch the routing diagram (check your deck or manual) – routing wrong can cause belt slip or premature wear.
• Common gotchas: The belt may feel slightly stiff when new; it will loosen after a few hours of use. If your deck vibrates or blades don’t engage fully after replacement, double-check the belt path and tensioner position.
• Durability: Rated 4.6/5 from 59 reviews, but some users note it wears faster than OEM on heavy-duty mowing (e.g., thick, wet grass). Stick to light-to-moderate use for best lifespan.

Should You Buy It

If you have a 42-inch John Deere 100 or LA100 series lawn tractor and need an affordable, drop-in replacement for light residential mowing, this belt is a solid value. Skip it if you mow commercially, have a larger deck, or want maximum longevity – in those cases, spend more on an OEM belt.