Oregon 42 Inch Lawn Mower Blades, Mower Blades for 42" Deck, 21-3/8" Length, Replacement for John Deere GY20850 and Fits John Deere 102, 105, 115, 125, LA100, LA105, LA110, LA115 and More (2 Pack)

What It Is

The Oregon 42-inch lawn mower blades are a direct replacement set for 42" cutting decks, specifically designed for John Deere LA-series and 100-series tractors. They deliver a clean cut for standard residential mowing on grass up to moderate height.

Fitment & Compatibility

Before buying, confirm your mower has a 42-inch deck and that the blade length is precisely 21-3/8 inches. These blades replace OEM John Deere part GY20850 and fit models including the 102, 105, 115, 125, LA100, LA105, LA110, and LA115. Measure your existing blade length—even within the same deck size, blade lengths vary (e.g., some 42" decks use 21" blades). Also verify the center hole diameter (usually 1-inch) and drive pin pattern match your spindle. These are aftermarket replacements, not genuine John Deere, so check for any deck-specific offset or airlift features.

Key Things to Buy

• Quality: Oregon is a reputable aftermarket brand; blades are heat-treated and balanced for durability. Expect similar performance to OEM at a lower price.
• Installation difficulty: Easy—requires a socket wrench and torque wrench (recommended 40-50 ft-lbs). Use a blade removal tool for safety.
• Common gotchas: Always check blade orientation—the curved edge should face upward toward the deck. Reuse your original washers and bolts. Never sharpen beyond 1/8" of edge loss.
• Warranty: Oregon offers a limited warranty against defects; inspect for cracks or warping before installing.

Should You Buy It

Yes, if you own a compatible John Deere 42" deck mower and want a reliable, affordable blade set from a trusted aftermarket brand. It’s ideal for routine seasonal replacements and delivers solid cut quality for typical lawn care. Avoid if you need OEM-only parts for warranty or have an unusual deck requiring specific blade geometry.