GX20072 Deck Belt for John Deere 42 inch, Replaces Part Number D100 D120 D130 E110 E120 E130 L100 L110 LA100 LA110 LA120 LA125 and More (1/2" x 104")

What It Is

This is a replacement deck belt for John Deere 42-inch mower decks, designed to drive the blades from the engine pulley. It fits a wide range of 100-series lawn tractors and is a direct substitute for OEM part GX20072.

Fitment & Compatibility

• Deck size: Only for 42-inch (107 cm) decks. Do not use on 48-inch or 54-inch decks.
• Models: Fits D100, D120, D130, E110, E120, E130, L100, L110, LA100, LA110, LA120, LA125, and many similar 100-series tractors. Check your model number on the frame or under the seat.
• Measurements: Belt is 1/2 inch wide x 104 inches long. Measure your old belt (lay it flat, measure end-to-end) to confirm length. If yours is 103.5–104.5 inches, this belt will work.
• OEM vs aftermarket: This is an aftermarket belt, not John Deere branded. It should match OEM specs, but quality can vary. Verify the belt profile (A-section or K-section) matches your pulleys—most 42-inch Deere decks use a standard A-section belt.

Key Things to Know

• Quality concerns: With only 3 reviews and a 3.7 rating, this is a budget option. Some users report shorter lifespan than OEM belts, especially in heavy use or wet grass.
• Installation difficulty: Easy—requires removing the deck or at least the belt guard. Route the belt around the engine pulley, spindle pulleys, and idler pulley as per your deck diagram (available online if lost).
• Common gotcha: The belt may feel stiff initially—let it run for 5-10 minutes at low throttle to seat properly. Check tension after the first hour; you may need to adjust the idler spring.
• Return policy: Check the seller’s return window before buying. If the belt is too tight or too loose, a quick return is essential.

Should You Buy It

This belt is a decent low-cost option if you need a quick replacement and don’t mow heavy or tall grass frequently. It’s not for commercial use or for owners who want OEM reliability—expect 1-2 seasons of light residential mowing. If you want longer life, step up to a name-brand aftermarket (e.g., Oregon or Stens) or the genuine John Deere part.