Ratioparts 3 Tooth Cutting Cutter 300mm Outside Diameter 25.4mm Bore Thickness 3mm Black

What It Is

This is a 300mm (approx. 12-inch) diameter cutting blade for ride-on mowers, zero-turn mowers, or large tractors. It’s designed for heavy-duty mulching or standard cutting on decks that accept a 25.4mm (1-inch) bore and 3mm blade thickness.

Fitment & Compatibility

Before buying, verify these three measurements:

• Outside Diameter: 300mm (11.8”). Must match your mower deck’s blade length—too long can strike the deck or spindle; too short leaves an uncut strip.
• Bore (center hole): 25.4mm (1”). Most zero-turn and ride-on mowers use this, but some older or compact models use 20mm or 7/8”. Measure your current blade’s center hole.
• Thickness: 3mm. Standard for residential-to-light-commercial decks. Not compatible with heavy-duty commercial spindles that require 4mm+ blades.

Check OEM part numbers or deck model (e.g., AYP, MTD, Husqvarna, Craftsman) for exact fit. This is an aftermarket blade—no warranty or dealer support from the original mower brand. If your deck uses a “star” or “keyed” center hole, this round-bore blade won’t fit.

Key Things to Know

• Quality: 4.1 stars from 27 reviews suggests decent steel but occasional balance issues. Inspect blade balance after installation.
• Installation: Straightforward—remove old blade, align bore, torque to spec (usually 40–60 ft-lbs). No special tools beyond a socket and torque wrench.
• Gotcha: The 3mm thickness is thinner than many OEM blades (often 3.5–4mm). It may wear faster on rocky or sandy soil.
• Mulching vs. Discharge: Not a dedicated mulching blade (no curved wings). Works best for standard cutting or bagging.

Should You Buy It

Buy this if you need a budget-friendly, standard 300mm blade for a common ride-on mower with a 25.4mm bore and don’t mind slightly faster wear. Skip it if you have a commercial deck, need a thicker blade for heavy debris, or require a specific OEM shape for your deck’s airflow.