GX20072 GY20570 42 inch Lawn Mower Deck Drive Belt Compatible with John Deere L100 L102 L105 L107 L108 L110 L111 L115 L118 L120 LA100 LA105 LA125 LA135 D100 D105 D110 D120 E110 E120 E130,1/2" X 104"

What It Is

This is a 42-inch lawn mower deck drive belt, 1/2 inch wide and 104 inches long, designed to transfer power from the engine pulley to the mower deck spindles on select John Deere lawn tractors. It’s a direct replacement for worn or broken OEM belts on residential riding mowers with 42-inch cutting decks.

Fitment & Compatibility

Before buying, confirm your mower has a 42-inch deck (not 38, 48, or 54 inch). This belt is compatible with John Deere L100, L102, L105, L107, L108, L110, L111, L115, L118, L120, LA100, LA105, LA125, LA135, D100, D105, D110, D120, E110, E120, and E130 models. It replaces OEM part numbers GX20072 and GY20570. Do not assume fitment based on model alone—measure your old belt length (should be 104 inches) and width (1/2 inch). Verify your deck has a single-belt drive system (not a two-belt setup). If your mower uses a different belt length (e.g., 100 or 108 inches), this will not fit.

Key Things to Know

• Quality: Aftermarket belt, typically made of rubber or Kevlar-reinforced material. It may wear faster than OEM but is acceptable for residential use with light-to-moderate mowing frequency.
• Installation difficulty: Moderate. You’ll need to remove the deck or at least the belt cover, route the belt around the engine pulley, idler pulleys, and spindle pulleys, and release tension using a spring-loaded idler. A belt diagram (available online) is recommended.
• Common gotchas: The belt may be slightly tighter or looser than OEM—check tension after installation. If your mower has a stamped deck, the belt can rub against sharp edges; inspect for wear after first few hours. Do not overtighten the idler arm; it can damage pulleys.
• Length verification: Some users report this belt measures closer to 103.5 inches when new. If your mower requires exact 104 inches (e.g., for a rigid spring tensioner), it may cause slippage. Measure your old belt before buying.

Should You Buy It

This is a solid budget option for casual homeowners who mow once a week and want a quick, functional replacement without paying OEM prices. It’s not ideal for commercial use or heavy-duty mowing (e.g., tall grass, frequent mulching), where a premium Kevlar or OEM belt will last longer. If you’re comfortable with a slight fitment risk and basic installation, it’s a good value.