918-04126B 618-04126 Spindle Assembly Fit for 50 inch Cub Cadet RZT50 LT1050 i1050 MTD Troy Bilt Mustang 50 Mower Deck Replaces 918-04126A 918-04126 918-04125B 618-04126A (3 Pack)

What It Is

This is a 3-pack of spindle assemblies for 50-inch mower decks, designed to drive the blades on Cub Cadet, MTD, and Troy-Bilt zero-turn and lawn tractors. It replaces worn or failed spindles that cause vibration, uneven cutting, or blade wobble.

Fitment & Compatibility

Check before buying:

• Deck size: Fits 50-inch decks only (not 42", 46", or 54").
• Models: Cub Cadet RZT50, LT1050, i1050; Troy-Bilt Mustang 50; MTD 50-inch decks. Also fits some Husqvarna, Craftsman, and John Deere models with the same spindle pattern—verify your OEM part number.
• OEM replacements: Replaces 918-04126A, 918-04126, 918-04125B, 618-04126A. If your spindle has one of these numbers stamped on it, this fits.
• Measurements: Spindle shaft is 5/8" diameter; bolt pattern is 3.75" center-to-center. Confirm your deck’s mounting holes match.
• Note: This is an aftermarket part, not OEM Cub Cadet. Quality is generally good, but some users report slight differences in bearing grease or housing finish.

Key Things to Know

• Installation difficulty: Moderate. Requires removing the deck, unbolting the old spindle, and transferring the pulley and blade. Basic hand tools (socket set, wrench) and a jack or blocks are needed.
• Common gotcha: The pulley nut is often reverse-threaded on some models—check before forcing. Use a thread locker on the new spindle bolts to prevent loosening.
• Bearing quality: These use sealed bearings, which last well if kept clean. Grease fittings are absent, so no maintenance needed—replace when worn.
• Warranty: Usually 1 year from the seller. Keep your deck clean and blades balanced to extend spindle life.

Should You Buy It

If you have a 50-inch Cub Cadet, MTD, or Troy-Bilt deck and need to replace one or all three spindles, this 3-pack is a cost-effective, well-rated choice. It’s ideal for DIY owners who want a drop-in replacement without paying OEM prices, but not for commercial use or decks with unusual bolt patterns.