Lawn Mower Blades Mulching with 42 inch Deck Fits for GY20850 AM137333 AM137328 AM141033 for John Deere X300 Z225 LA120 LA125 LA135 X105 X110 X120, 2 PCS

What It Is

This is a set of two mulching blades designed for 42-inch cutting decks on select John Deere lawn tractors, replacing OEM part numbers GY20850, AM137333, AM137328, and AM141033. They are intended for mulching grass clippings into fine particles to return nutrients to the lawn, rather than bagging or side-discharging.

Fitment & Compatibility

• Deck size: Only fits 42-inch (107 cm) decks. Measure your deck width to confirm.
• Model compatibility: Listed for John Deere X300, Z225, LA120, LA125, LA135, X105, X110, X120. Verify your specific model and year – not all 42-inch decks use the same blade pattern.
• OEM cross-reference: Direct replacements for GY20850, AM137333, AM137328, AM141033. If your current blade has a different OEM number, do not assume fit.
• Measurements: Typically 21 inches long, 0.25 inches thick, with a 1-inch center hole and 7-point star drive. Measure your old blade’s length, thickness, and hole pattern before ordering.
• Aftermarket note: These are non-OEM blades. They may have slightly different balance or metal hardness than genuine John Deere parts.

Key Things to Know

• Installation difficulty: Easy – requires a socket or wrench to remove the blade bolt (usually 15/16″ or 5/8″). Use a block of wood to lock the blade. Torque to 55-65 ft-lbs.
• Sharpening: Mulching blades are designed with a longer cutting edge and more lift. They can be sharpened, but aftermarket blades may not hold an edge as long as OEM.
• Balance check: Always check blade balance after installation (use a blade balancer or hang on a nail). Unbalanced blades cause vibration and deck damage.
• Mulching performance: These blades work best with a mulching plug or cover installed on the deck. Without it, they function like standard lift blades but won’t mulch effectively.

Should You Buy It

If you own one of the listed John Deere models with a 42-inch deck and want an affordable mulching blade set for regular lawn maintenance, this is a solid budget option. It’s not for heavy-duty commercial use or if you need exact OEM fitment – but for home owners looking to reduce bagging and recycle clippings, it delivers good value at this price point.