54 Inch Mower Deck Fits Cub Cadet RZT-54 S54 L54 ZT1-54 ZT2-54 XT1-ST54 GT54 XT2-54 GX54 Troy Bilt Mustang XP TB2454 Craftsman T8400 G8400 Z6660 Replaces 618-06978 918-06978 Spindle Assembly 3 PACK

What It Is

This is a 3-pack of aftermarket spindle assemblies designed for 54-inch mower decks used on Cub Cadet, Troy Bilt, and Craftsman zero-turn and lawn tractors. Each spindle houses the bearings and shaft that drive the blade, making it a direct replacement for worn or failed OEM spindles.

Fitment & Compatibility

• Deck size must be 54 inches – this kit will not fit 42, 46, or 50-inch decks.
• Compatible models include: Cub Cadet RZT-54, S54, L54, ZT1-54, ZT2-54, XT1-ST54, GT54, XT2-54, GX54; Troy Bilt Mustang XP, TB2454; Craftsman T8400, G8400, Z6660.
• Replaces OEM part numbers 618-06978 and 918-06978.
• Measure your existing spindle – confirm the shaft diameter, pulley bolt pattern, and housing height match before purchase. Aftermarket spindles can vary slightly from OEM, especially in housing thickness or bearing quality.
• Check pulley compatibility – some aftermarket spindles use a different pulley offset or bolt pattern; you may need to reuse your original pulley if it’s in good condition.

Key Things to Know

• Quality is decent for the price – these are budget-friendly replacements, but bearings may not last as long as OEM. Expect 1-3 seasons under normal use.
• Installation is straightforward – remove the deck, unbolt the old spindle, and bolt in the new one. You’ll need basic hand tools and a torque wrench (specs: 30-40 ft-lbs for spindle bolts).
• Common gotcha: The spindle shaft may have a slight wobble out of the box. Spin it by hand before installing – if it’s not smooth, return it. Also, check that the blade bolt hole is centered.
• You get three spindles – replace all at once to avoid uneven cutting and future downtime. Mixing old and new spindles can cause deck imbalance.

Should You Buy It

This is a solid budget option if you need to replace all three spindles on a 54-inch deck and don’t want to pay OEM prices. It’s best for DIY owners who can handle installation and don’t mind slightly shorter bearing life. If you’re a heavy commercial user or need maximum durability, stick with OEM assemblies.