8TEN Spindle Blade Kit for Ariens 21549012 AYP 138971 532138971 187292 Husqvarna 587125401 42 inch Deck Medium-Lift

What It Is

This is a 3-blade set of medium-lift mower blades designed to replace OEM spindles on 42-inch cutting decks. It’s intended for residential and light commercial mowing on Ariens, Husqvarna, AYP, and Craftsman tractors, providing a balance of cutting performance and bagging capability.

Fitment & Compatibility

Before buying, verify your deck is exactly 42 inches (measured blade tip to blade tip) and uses a 5-point star spindle pattern. These blades replace OEM part numbers 21549012 (Ariens), 138971 / 532138971 (AYP/Husqvarna), and 587125401 (Husqvarna). They also fit many Husqvarna, Poulan, and Craftsman models from the 2000s onward. Measure your existing blade length (should be 20.5 inches) and center hole diameter (7/16 inch). If your spindle uses a different mounting pattern or your deck is 46 or 48 inches, this kit won’t work.

Key Things to Know

• Quality vs. OEM: These are aftermarket blades—slightly thinner gauge steel than genuine Husqvarna parts. They’ll cut fine but may wear faster on rocky or sandy soil.
• Installation difficulty: Straightforward if you have a socket set and torque wrench. You’ll need to remove the old blades, clean the spindle, and torque the new ones to 50–60 ft-lbs. No special tools required.
• Common gotcha: The medium-lift design is optimized for bagging, not mulching. If you prefer leaving clippings on the lawn, these may leave windrows. Also, the blades come unsharpened—sharpen them before first use for best results.
• Balance: Each blade should be balanced before installation. Unbalanced blades cause vibration, premature spindle wear, and uneven cuts. Use a blade balancer (under $10) to check.

Should You Buy It

If you need a budget-friendly replacement for a 42-inch Ariens, Husqvarna, or AYP deck and primarily bag or side-discharge, this kit is a solid value. It’s not ideal for mulching or heavy-duty commercial use, but for regular residential mowing, it’ll get the job done at half the price of OEM.