50 Inch Deck Spindle Assembly Replacement 618-09256 618p09256 Fits for Cub Cadet Ultima ZT1-50 ZT2-50 MTD Craftsman Z5600 Z5650 Troy Bilt Mustang Z50 XP Lawn Mower

What It Is

This is a replacement deck spindle assembly for 50-inch mower decks. It’s the rotating hub that drives the blade, designed for zero-turn and tractor mowers used in residential and light commercial mowing.

Fitment & Compatibility

Before buying, confirm your mower has a 50-inch stamped or fabricated deck. This spindle (OEM #618-09256 / 618p09256) fits Cub Cadet Ultima ZT1-50, ZT2-50, and MTD-built models like Craftsman Z5600, Z5650, and Troy-Bilt Mustang Z50 XP. It may also fit other MTD/Cub Cadet 50-inch decks from 2015–2023. Do not assume universal fit—measure your spindle housing diameter (typically 1.5-inch bearing bore) and bolt pattern (4-bolt, 3.25-inch center-to-center). Check your deck’s spindle pulley height and shaft length (usually 1-inch diameter, 2.5–3 inch exposed shaft). If your current spindle has a different pulley or housing shape, this may not align.

Key Things to Know

• Build quality: This is an aftermarket replacement, not OEM, but reviews indicate it matches OEM specs. It includes bearings and a shaft pre-assembled—no pressing required.
• Installation difficulty: Moderate (30–60 minutes). You’ll need a socket set, a jack or blocks to lift the mower, and a torque wrench (tighten spindle bolts to 30–40 ft-lbs). Expect to remove the deck, belt, pulley, and blade.
• Common gotchas: The pulley retaining bolt may be reverse-threaded on some models—check before forcing. Also, ensure the spindle belt tensioner is released before removal to avoid damage.
• Warranty: Typically 90-day limited. Not for heavy commercial use—designed for residential/occasional commercial mowing.

Should You Buy It

If you have a compatible 50-inch Cub Cadet or MTD zero-turn/tractor and need a direct-fit replacement without paying OEM prices ($70+), this is a solid value. It’s best for DIYers comfortable with basic deck disassembly. For commercial fleets or high-hour use, consider OEM for longer bearing life.