John Deere GX21784 Mower Blades Set of 3 for 48" Decks — OEM fit, hardened carbon/boron steel

These are genuine John Deere OEM GX21784 replacement mower blades sold as a set of three for compatible 48" decks and select lawn tractor models.

When your mower’s cutting performance drops, replacing worn or damaged blades with factory-spec parts restores even cutting, reliable balance and longer blade life. This three-pack of GX21784 blades matches John Deere original equipment specifications for dimensions, hole placement and metal hardness so they fit and perform like the blades that came with your tractor.

Which machines will these GX21784 blades fit?

These blades are designed for a broad range of John Deere mid-frame and lawn-tractor models that use a 48" deck or equivalent mounting pattern. Check your tractor’s manual or existing blade part number to confirm compatibility before purchasing.

• Common fits include 145, 155C, D140–D160 series, E140–E170 series and many LA and X Series tractors.
• Also used on Ztrak and select snow-blower/collection-system-equipped decks where the GX21784 is specified.
• Exact fit requires matching blade hole diameter and cut length to your mower spindle.

What are the key dimensions and materials of these blades?

The GX21784 blades are manufactured to John Deere’s OEM tolerances for secure mounting, balanced rotation and consistent cut length. Material choices and finish help resist wear and preserve the cutting edge under normal operating conditions.

• Overall length: 17.047 inches; width: 2.750 inches; thickness: 0.156 inches.
• Wing height 1.220 inches and cut length 4.921 inches for the intended air flow and lift pattern.
• Mounting hole diameter: 0.689 inches; constructed from hardened carbon/boron alloy for durability.

Why choose OEM GX21784 blades instead of aftermarket alternatives?

OEM blades are produced to the original John Deere specifications so they match blade balance, hole placement and edge geometry. That reduces vibration, improves cut quality and minimizes the chance of interference with deck components compared with poorly matched aftermarket blades.

• Factory part numbers: GX21784 (also referenced as AM141035, GY20852, GX21786).
• Made from a carbon/boron steel blend to maintain edge hardness and resist breakage.
• Sold in a convenient three-pack to service the full 48" deck at once.

How do I install and care for these blades to get the best life?

Install blades following your tractor manual torque specs and direction indicators — incorrect orientation or loose hardware causes vibration and poor cutting. Regular sharpening, inspection for cracks or bends, and prompt replacement after impact will extend deck performance and safety.

• Balance blades after sharpening to prevent vibration and spindle wear.
• Replace any blade with visible bends, cracks or severe metal loss—do not attempt repairs on compromised blades.
• Use proper mounting hardware and torque values as specified by John Deere.

Who this is for: Lawn owners and maintenance professionals who operate John Deere lawn tractors or Ztrak mowers with 48" decks and require genuine OEM replacement parts for consistent cut quality and reliable fit. Choose this GX21784 three-pack if your model lists this part number or you need an exact OEM match to maintain factory performance and balance.