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 (3-Pack)

What It Is

This is a 3-pack of replacement spindle assemblies designed for the 50-inch cutting decks on select Cub Cadet, Troy Bilt, and Craftsman zero-turn and garden tractors. Each spindle houses the bearings and pulley that drive a mower blade; you replace the entire assembly when bearings fail or the spindle shaft is bent.

Fitment & Compatibility

Before buying, confirm your deck is exactly 50 inches (measured blade tip to blade tip). This 3-pack fits Cub Cadet models ZT1-50, XT1-GT50, RZT-L50, RZT-S50, Troy Bilt Super Mustang 50, and Craftsman Z550 zero-turn mowers. The OEM part numbers are 618-06980 and 918-06980. Measure the mounting hole pattern (typically 3 bolts on a 3-inch center) and the spindle shaft diameter (should be 5/8 inch). If your deck uses a 1-inch shaft or different bolt pattern, these won’t work. Check your mower’s model number tag—this kit is aftermarket, not genuine Cub Cadet, but is a direct fit for those listed decks.

Key Things to Know

• Quality vs. OEM: Aftermarket spindles are often 20-40% cheaper than genuine Cub Cadet parts. They use standard bearings but may not last as long under heavy commercial use.
• Installation difficulty: Moderate. You’ll need a socket set, a jack to lift the mower, and possibly a puller to remove old spindles. Plan 1–2 hours for all three.
• Common gotcha: The pulley bolt can be seized. Apply penetrating oil the night before. Also, note the blade orientation—spindles are handed (left/right rotation) on some decks; this kit usually includes all the same rotation, so check your old spindles before swapping.
• Bearing life: Expect 150–300 hours of mowing before bearings wear, depending on debris and lubrication. Grease fittings are not included; consider adding a shot of grease annually if your deck has zerks.

Should You Buy It

Buy this 3-pack if you have one of the listed 50-inch Cub Cadet, Troy Bilt, or Craftsman models and want to replace all three spindles at once for a reasonable price. It’s ideal for homeowners who mow a few acres and don’t need commercial-grade longevity. If you’re a pro or want the absolute longest life, spring for genuine OEM spindles. For most DIYers, this is a solid value.