Set of 3, New Spindle Assembly 50" RZT for MTD Cub Cadet LGTX1050 RZT50 LT1050 918-04125B 918-04126 618-04126 918-04125 618-04125

What It Is

This is a set of three replacement spindle assemblies for 50-inch MTD and Cub Cadet zero-turn mowers. Each spindle houses the bearings and shaft that spin your mower blades, and this kit is designed to replace worn or failed OEM spindles on RZT models like the RZT50, LGTX1050, and LT1050.

Fitment & Compatibility

Before buying, confirm your mower has a 50-inch stamped steel or fabricated deck—this kit will not fit 42-inch or 54-inch decks. Verify your OEM part numbers: 918-04125B, 918-04126, 618-04126, 918-04125, or 618-04125. This set is an aftermarket replacement, not genuine Cub Cadet, but it matches the factory bolt pattern and shaft dimensions. Measure the spindle bolt hole spacing (typically 2.75 inches center-to-center) and shaft diameter (0.625 inch) to be sure. Also check that your deck has three spindles—some 50-inch decks use two.

Key Things to Know

• Quality vs OEM: These are aftermarket spindles; they use standard bearings that may not last as long as OEM. Expect 1-2 seasons of residential use before needing replacement.
• Installation difficulty: Moderate. You’ll need basic tools (wrenches, socket set, possibly a puller) and about an hour per spindle. Removing old spindles can be tough if rusted. Use anti-seize on the new bolts.
• Common gotcha: The spindle pulley may not perfectly align with the deck’s belt routing—check belt tension and adjust idler pulleys if needed after installation.
• Includes hardware? Typically comes with bolts and lock washers, but not the pulley or blade. Reuse your old pulleys if they’re in good shape.

Should You Buy It

If you’re on a budget and need a quick fix for a worn spindle on a residential Cub Cadet or MTD zero-turn with a 50-inch deck, this kit offers good value. It’s not built for heavy commercial use, but for the price and high user rating, it’s a solid choice for DIY repairs.