618-06981 918-06981 Spindle Assembly - Fits 50 Inch Mower Decks Cub Ca det XT1-LT50 XT2-LX50 XT1 LT50 XT2 LX50 MTD Columbia CYT5023SE Troy Bilt TB2350 (1-Pack)

What It Is

This spindle assembly (part #618-06981 / 918-06981) is the rotating hub that drives the mower blade on 50-inch cutting decks. It’s a direct replacement for worn or noisy spindles on Cub Cadet XT1-LT50, XT2-LX50, MTD, Columbia, and Troy-Bilt models with 50-inch fabricated or stamped decks.

Fitment & Compatibility

Before buying, physically measure your existing spindle housing and blade mount. Common OEM part numbers include 618-06981, 918-06981, 718-06981, and 918-06981A. This fits Cub Cadet XT1 LT50, XT2 LX50, MTD 50-inch decks (e.g., model 13AJ615G), Columbia CYT5023SE, and Troy-Bilt TB2350. Check your deck’s spindle bolt pattern – this uses a 3-bolt triangular mount (holes ~2.75 inches apart center-to-center). Verify the spindle shaft diameter (typically 5/8 inch) and that the blade bolt is 5/16-24 thread. If your deck uses a different bolt pattern or shaft size, this won’t work.

Key Things to Know

• Quality vs OEM: Aftermarket spindle may have less precise bearings than OEM Cub Cadet. Expect moderate lifespan (1-3 seasons under normal use). Some users report slight wobble out of the box – spin the shaft before installing.
• Installation: Moderate difficulty. You’ll need a socket set, torque wrench (spec ~30-40 ft-lbs for mounting bolts), and a blade removal tool. Replace all three spindles if one fails – uneven wear stresses the deck.
• Common gotcha: The included grease fitting is often plastic and can snap off. Consider adding a metal zerk fitting. Also, the pulley mounting hole may need slight filing to align with your deck’s pulley.
• Check bearings: Spin the spindle by hand before mounting – rough or gritty rotation indicates a defective unit. Return immediately.

Should You Buy It

If you’re on a tight budget and need a quick fix for a worn spindle on a 50-inch deck, this aftermarket part works for light-duty residential mowing. But if you mow heavy grass or rough terrain, or want maximum longevity, spring for an OEM Cub Cadet spindle (part 918-06981A) – the bearings will last longer and fit more precisely.