Mower Deck Belt GX20072 for John Deere LA105 LA115 L110 D110 L100 L130 L1742 D100 D120 D130 GY20570 42 inch Deck Riding Lawn Mowers(1/2" x 104")

What It Is

This is a replacement mower deck belt (1/2" x 104") designed to drive the blades on 42-inch cutting decks for select John Deere riding mowers. It’s for standard residential mowing—not zero-turn or heavy commercial use.

Fitment & Compatibility

Before buying, confirm three things:

• Deck size: Must be exactly 42 inches. This belt does not fit 38", 48", or 54" decks.
• Model: Fits John Deere LA105, LA115, L110, D110, L100, L130, L1742, D100, D120, D130. Also listed for D140 and D160, but double-check your deck size.
• Measurements: Belt is 1/2" wide x 104" long (OEM equivalents: GX20072, GY20570). Measure your old belt length (lay it flat, measure end to end) and width. Aftermarket belts may vary slightly in thickness or material—verify the cross-section is a standard “A” belt (1/2" top width).

Don’t rely on model number alone. Some John Deere models came with multiple deck sizes. Measure your deck or check the belt part number stamped on the old belt.

Key Things to Know

• Quality: This is an aftermarket belt, not OEM John Deere. Expect it to last 1-2 seasons with regular use. OEM belts may last longer but cost 2-3x more.
• Installation: Moderate difficulty. You’ll need to remove the deck (or at least the belt guard), release tension from the idler pulley, and route the belt per your deck diagram. Take photos before removal.
• Common gotchas: The belt may be slightly tight on new pulleys. If it squeals after installation, check tension and alignment. Also, this belt is not reinforced with Kevlar—avoid heavy debris or wet grass to prevent premature wear.
• Check pulleys first: Worn or seized pulleys will shred a new belt quickly. Spin each pulley by hand; replace any that are rough or wobble.

Should You Buy It

If you need a budget-friendly replacement for a 42-inch John Deere riding mower deck belt and you’re comfortable with a simple DIY swap (removing the deck, routing the belt), this is a solid pick. It’s not for commercial use or for mowers with 38-inch or 48-inch decks. For the price, it’s a good value—just verify fitment and inspect your pulleys first.