Arnold 490-110-0087 Mower Blades

These blades are designed to fit 40-inch Murray lawn tractor decks. They serve as a direct replacement for Murray part number 91871, so if your manual lists that part number, these will fit.

High lift blades are designed with a more aggressive angle on the trailing edge. This creates extra airflow, which is essential for forcefully pushing grass clippings up into your mower's bagger rather than leaving them on the lawn.

While these are optimized for bagging, they are 3-in-1 blades, meaning they can also mulch or discharge. However, because they are specifically engineered for high lift, they may not mulch as cleanly as a dedicated mulching blade.

Installation requires standard tools like a socket wrench and a way to safely secure the blade while you loosen the mounting bolt. The blades feature a standard 0.85-inch round center hole, making them a straightforward swap for your existing hardware.

You should replace your blades whenever they become dull, chipped, or bent, typically once or twice a season depending on your lawn size and terrain. If you notice your grass tips are turning brown or ragged after mowing, it is a clear sign your blades need replacing.