8TEN Mower Spindle for MTD Cub Cadet Troy Bilt RTZ54 ZT54 GT1554 618-04608A 918-04608A 918-0671B

What It Is

This is a replacement spindle assembly for the cutting deck on select MTD, Cub Cadet, and Troy-Bilt zero-turn and lawn tractors. It houses the blade pulley and bearing, allowing the blade to spin freely. Designed for decks on machines like the Cub Cadet RTZ54, ZT54, and GT1554.

Fitment & Compatibility

Before buying, confirm your mower uses a 42-inch or 54-inch deck with a 5/8-inch spindle shaft diameter. This spindle replaces OEM part numbers 618-04608A, 918-04608A, and 918-0671B. It fits MTD, Cub Cadet, and Troy-Bilt models with those part numbers—not all Cub Cadet decks. Measure the bolt pattern (typically 3-bolt, 3-inch center-to-center) and shaft length (usually 2.5 inches). Verify your deck’s pulley and blade mounting holes match. If your mower uses a different spindle shaft diameter (e.g., 1-inch), this won’t work.

Key Things to Know

• Quality vs OEM: The 8TEN spindle is aftermarket, not genuine Cub Cadet. It’s generally reliable for the price but may have slightly shorter bearing life than OEM.
• Installation difficulty: Moderate. You’ll need basic tools (wrenches, socket set) and may need to remove the deck or belt. Expect 30–60 minutes per spindle.
• Common gotchas: The included bolts may not match your deck’s thread pitch—check your old bolts first. Also, the spindle may feel tight when new; that’s normal as bearings seat.
• When to replace: If the blade wobbles, the deck vibrates excessively, or the bearing is noisy/gritty, replace the spindle immediately to avoid blade damage or deck cracking.

Should You Buy It

If you need an affordable replacement for a worn spindle on a compatible MTD/Cub Cadet/Troy-Bilt deck and are comfortable with basic mechanical work, this is a solid value. Avoid if you want OEM longevity or have a less common deck with different bolt patterns.