GX21380 Medium Lift Mower Blades for John Deere 54 Inch Deck D170 E180 G110 S180 190C LA150 54" Lawn Mower Replace GY20684 GY20679 GY20686 7-Point Star/Medium Lift / 3 Pack

What It Is

This is a set of three aftermarket medium-lift mower blades designed for 54-inch John Deere decks. They replace OEM part numbers GY20684, GY20679, and GY20686, and are intended for mulching and bagging on residential John Deere lawn tractors.

Fitment & Compatibility

Before buying, confirm your mower has a 54-inch stamped deck and uses a 7-point star center hole (most common on Deere 100-series and select 200/300-series). This set fits models D170, E180, G110, S180, 190C, and LA150, but also works on X300/X500 series with the same deck. Measure your existing blade length: these are 21 inches long with a 0.25-inch thickness and 2.75-inch width. Verify the OEM number on your current blade—if it’s GY20684 (right), GY20679 (center), or GY20686 (left), these are direct replacements. Not compatible with 48-inch or 60-inch decks, or older 54-inch decks using a 5-point or oval hole pattern.

Key Things to Buy

• Medium lift vs. high lift: Medium lift balances bagging and mulching; don’t use for heavy leaf mulching where high-lift blades are better.
• Installation: Torque the center bolt to 55-65 ft-lbs (check your deck manual). Re-use the original washers and spacers—these blades come without hardware.
• Balance check: Aftermarket blades may need balancing before installation. Use a blade balancer to avoid vibration and spindle wear.
• Deck cleaning: Remove grass buildup under the deck before installing to prevent clipping clogs and ensure proper airflow.

Should You Buy It

If you need a cost-effective replacement for a 54-inch John Deere deck and your current blades are dull or damaged, this is a solid choice for standard residential mowing and occasional bagging. Avoid if you require heavy-duty mulching or high-lift performance for wet grass.