4PK Lawn Mower Blades Replacement for John Deere 42" GX22151 GY20850 D100 D105 D110 D120 D130 LA100 LA105 LA110 LA115 LA120 LA125 LA135

What It Is

This is a set of four replacement blades for 42-inch John Deere lawn tractors. Designed for medium-to-large residential lawns, these blades lift and cut grass, then discharge or bag clippings. The set covers multiple popular D100 and LA100 series models.

Fitment & Compatibility

Before buying, confirm your mower has a 42-inch deck (not 48 or 54). This set fits John Deere models D100, D105, D110, D120, D130, LA100, LA105, LA110, LA115, LA120, LA125, and LA135. It replaces OEM part numbers GX22151 and GY20850. Measure your blade length: these are approximately 21 inches long, with a 1-inch center hole and a 0.75-inch offset (check your current blade’s measurements). If your mower uses a different spindle or offset, this set won’t work. Always verify your model number on the deck’s sticker under the mower.

Key Things to Know

• Quality & material: Aftermarket blades made of hardened steel. They’re slightly thinner than OEM but still durable for regular residential use. Expect a 1–2 season lifespan on average lawns.
• Installation: Straightforward if you have a socket wrench and a blade removal tool. Lift the deck or remove blades with the mower off and spark plug disconnected. Torque bolts to 70–90 ft-lbs. Use a block of wood to jam the blade when loosening.
• Common gotcha: The set includes four blades, but some 42-inch decks use only three. Check your deck’s spindle count before opening the package.
• Balance: These come pre-balanced, but it’s worth checking each blade on a balancer to avoid vibration and uneven cut.

Should You Buy It

If you own one of the listed John Deere models and want a budget-friendly replacement for worn or dull blades, this set delivers solid value. It’s not for commercial use or heavy-duty mulching, but for typical weekly mowing on a 1–2 acre lot, it’s a reliable choice. Just double-check your deck size and spindle count first.