42" Mower Deck Belt GX20072 1/2" X 104" Replacement for John Deere LA115 LA110 LA105 D100 D105 D110 D125 D130 E100 E110 E120 E130 X105 X106 X126

What It Is

This is a replacement mower deck belt, 1/2 inch wide and 104 inches long, designed to transfer power from the engine pulley to the spindle blades on 42-inch cutting decks. It’s for John Deere lawn tractors in the 100, LA, and X100 series, and is a common wear item needing replacement every 1-3 seasons depending on use.

Fitment & Compatibility

Before buying, confirm your deck size is exactly 42 inches—this belt won’t fit 38-inch or 48-inch decks. Check your model against the list: LA105, LA110, LA115, D100, D105, D110, D125, D130, E100, E110, E120, E130, X105, X106, X126. Also verify the belt length with a tape measure on your old belt (end-to-end, not including slack); it must be 104 inches. This is an aftermarket replacement for OEM part GX20072, so it’s not a John Deere-branded belt—expect slightly different rubber compound or construction. Measure the belt path routing before removing the old one (take a photo) to avoid confusion.

Key Things to Know

• Quality vs OEM: Aftermarket belts like this can wear faster or stretch more than genuine John Deere belts, especially under heavy use or in wet grass. Expect 1-2 seasons of life versus 2-3 for OEM.
• Installation difficulty: Moderate. You’ll need to remove the deck or at least the belt guard, release tension from the idler pulley, and route the belt correctly. A belt tension gauge or a 1/2-inch socket for the idler bolt helps.
• Common gotcha: The belt must be routed under all spindle pulleys and over the tensioner—wrong routing causes slipping, noise, or blade stall. Check your deck’s belt diagram (often printed on the deck top) or look it up online.
• Price vs value: At $10.99, it’s a budget option. If you mow a large lawn or have tough terrain, spending more on a branded belt might reduce replacement frequency.

Should You Buy It

This belt is a solid choice for budget-conscious DIYers who mow a standard residential lawn and don’t mind replacing it yearly. If you need maximum durability for heavy commercial use or want exact OEM fit without guesswork, spend extra on a genuine John Deere GX20072 belt.