GX20072 John Deere 42 inch Deck Belt for Cub Cadet 103.7inch Lawn Mower D105 D100 D110 D120 D125 D130 D140 S100 L110 L120 L140 E100 LA105 LA115 LA145 E130 GY20570 Aramid Cord

What It Is

This is a 42-inch deck drive belt for select Cub Cadet and John Deere lawn tractors (D100–D140, S100, L100–L140, E100–E130, LA100–LA145 series). It transfers engine power to the mower blades for cutting grass.

Fitment & Compatibility

Before buying, verify:

• Deck size: Fits only 42-inch cutting decks (not 46-inch or 54-inch).
• OEM cross-references: Replaces John Deere part GX20072 and Cub Cadet part 103.7inch (GY20570). Check your owner’s manual or old belt part number.
• Belt dimensions: 42-inch length, 1/2-inch width, 5/8-inch top width. Measure your old belt if unsure.
• Model fit: Confirmed for Cub Cadet D100–D140, S100, L100–L140, E100–E130, LA100–LA145 series. Also fits John Deere D105, D100, D110, D120, D125, D130, D140, S100, L110, L120, L140, E100, LA105, LA115, LA145, E130.
• Aftermarket note: This is a non-OEM belt (Cub Cadet branded). It may vary slightly in length from original—check tension after installation.

Key Things to Know

• Quality: Aramid cord construction is stronger than standard rubber belts, reducing stretch and breakage under load.
• Installation: Moderate difficulty—requires removing deck or routing belt around pulleys and tensioner. Have a wrench and belt diagram handy (often under the deck or in manual).
• Common gotchas: Belt may be slightly longer than OEM—adjust tensioner accordingly. If it slips, double-check routing; incorrect path causes premature wear.
• Durability: Aramid cord resists heat and abrasion better than Kevlar alternatives, but still needs replacement every 2–3 seasons with regular use.

Should You Buy It

If you need a reliable, budget-friendly replacement for a 42-inch deck belt on a Cub Cadet or John Deere tractor listed above, this is a solid choice—especially if you want aramid cord strength without paying OEM prices. Just confirm your deck size and routing diagram before buying.