618-06980 918-06980 Spindle Assembly - Fits Cub Cadet 50" Deck Cub Cadet ZT1-50 XT1-GT50 RZT-L50 RZT-S50 Troy Bilt Super Mustang 50 Deck Craftsman Z550 Zero Turn Mower (1-Pack)

What It Is

This spindle assembly (OEM #618-06980 / 918-06980) is the rotating hub that drives your mower blade. It’s designed for 50-inch cutting decks on Cub Cadet, Troy-Bilt, and Craftsman zero-turn and lawn tractors.

Fitment & Compatibility

Check these before buying:

• Deck size: This fits only 50-inch decks. Measure your deck width—if it’s 46" or 54", this won’t work.
• Models: Confirmed for Cub Cadet ZT1-50, XT1-GT50, RZT-L50, RZT-S50; Troy-Bilt Super Mustang 50; Craftsman Z550. Verify your model number on the deck or frame tag.
• OEM vs aftermarket: This is an OEM Cub Cadet part. Aftermarket alternatives may vary in bearing quality and shaft hardness—this one is direct-fit.
• Physical check: Spindle shaft is 5/8" diameter, bolt pattern is 3-bolt (3.5" center-to-center). Measure your old spindle before ordering.

Key Things to Know

• Bearing quality: OEM spindles use sealed bearings that last longer than budget replacements—worth the slight premium.
• Installation difficulty: Moderate. You’ll need a socket set, torque wrench (tighten to 30-40 ft-lbs), and possibly a puller if the old spindle is seized.
• Common gotcha: The pulley may be tight on the shaft—use anti-seize during reassembly to prevent future removal issues.
• Deck removal: You’ll likely need to remove the deck or at least raise it high for access. Have jack stands or blocks handy.

Should You Buy It

If you need a direct, no-guesswork replacement for a Cub Cadet or compatible 50-inch deck spindle, this is a solid choice. It’s priced competitively with aftermarket options but delivers OEM fit and reliability. Best for DIYers with basic mechanical skills who want to avoid chasing fitment problems.