42 inch Mower Deck Belt Made with Aramid Compatible with John Deere GX20072 GY20570 115 125 135 D100 D105 D110 D120 D125 D130 E100 E110 E120

What It Is

This is a 42-inch mower deck drive belt made with aramid (Kevlar-like) fibers, designed to transfer power from the engine pulley to the spindle and blade pulleys on select John Deere lawn tractors. It’s a direct replacement for OEM belts GX20072 and GY20570.

Fitment & Compatibility

Before buying, confirm your mower has a 42-inch stamped steel deck (not a 48-inch or 54-inch). This belt fits John Deere 100 Series tractors: models 115, 125, 135, D100, D105, D110, D120, D125, D130, E100, E110, and E120. It also works on some older L100/L110/L120/L130 models. Measure your old belt length end-to-end – it should be about 92.5 inches (the OEM spec). If your belt is longer or shorter, this won’t fit. The aftermarket aramid belt is not an OEM John Deere part, but it matches the same dimensions and pulley routing.

Key Things to Know

• Aramid vs. standard rubber: Aramid is stronger and more heat-resistant than basic rubber belts, often lasting longer under heavy grass or frequent use. It’s less prone to stretching.
• Installation difficulty: Moderate – you’ll need to remove the deck (or at least the belt guard) and release the tensioner pulley to route the belt. A diagram or photo of the original routing helps.
• Common gotcha: This belt is for the drive belt that spins the blades, not the transmission drive belt. Don’t mix them up – the transmission belt is shorter and sits under the tractor.
• Check deck condition: Worn pulleys or a bent tensioner arm can cause premature belt wear. Spin each pulley by hand to feel for roughness or wobble before installing.

Should You Buy It

If you have one of the listed John Deere models with a 42-inch deck and need a durable, budget-friendly alternative to the OEM belt, this is a solid pick. The aramid construction offers good longevity for the price, and the 4.4-star rating from nearly 800 buyers backs up its reliability. Just double-check your deck size and measure your old belt to avoid a return.