Mulching Mower Blade Compatible with Ryo bi 20 Inch Lawn Mower, Replaces for 635373 33120BDB and 514061-49 (1 Pack)

What It Is

This is a mulching blade designed for Ryobi 20-inch walk-behind mowers. It replaces OEM parts 635373, 33120BDB, and 514061-49. Mulching blades use a curved, serrated edge to cut grass into finer clippings that decompose faster, returning nutrients to the lawn.

Fitment & Compatibility

Before buying, confirm three things:

• Deck size: Must be exactly 20 inches (center hole to blade tip). Measure your current blade from center hole to tip and double it.
• Model number: Fits Ryobi 20-inch models like RY40180, RY40180-US, RY40180A, RY40190, RY40190-US, RY40190A, and others using the OEM part numbers listed. Check your owner’s manual or current blade’s part number.
• Mounting hole: Center hole is 1-inch diameter, with a 5-point star pattern for Ryobi’s proprietary spindle. Will not fit universal or non-Ryobi spindles.

Key Things to Know

• Installation difficulty: Easy. Requires a socket wrench (usually 5/8-inch or 15mm) to remove the center nut. Torque to 30–40 ft-lbs. Use thread locker if not pre-applied.
• Mulching performance: Expect finer clippings than standard blades, but only on dry, short grass. Wet or tall grass will clump and discharge poorly.
• Durability: Steel construction with a painted finish. Sharpening is possible but shortens life; replace when nicked or bent. Check for balance before installing.
• One pack: This is a single blade. Many 20-inch mowers use one blade, but verify yours doesn’t require two (uncommon for this size).

Should You Buy It

Buy this if you own a compatible Ryobi 20-inch mower, want finer clippings for mulching, and prefer an aftermarket replacement over OEM. Skip it if you need a bagging or side-discharge blade, or if your mower uses a different spindle pattern. For the price, it’s a solid budget option with decent reviews.