CUB CADET 603-08721-4021 Yellow Front Caster Wheel Yoke Ultima ZTS1 ZTS2 KH Fab

What It Is

The Cub Cadet 603-08721-4021 is an OEM yellow front caster wheel yoke assembly designed for zero-turn mowers. It holds the front caster wheel and allows steering pivoting on Ultima ZTS1 and ZTS2 models, as well as KH Fab commercial mowers.

Fitment & Compatibility

Before buying, verify three things:

• Model series: Fits Cub Cadet Ultima ZTS1, ZTS2, and KH Fab zero-turn mowers. Not universal for all Cub Cadet models.
• Deck size: Typically works with 42–60-inch decks on these series, but confirm your specific model number (e.g., ZTS1 54, ZTS2 60).
• Measurements: The yoke’s spindle bore diameter is 5/8 inch, and the wheel stud pattern is 4 on 4 inches. Measure your existing yoke’s bolt spacing and spindle shaft diameter to match.
• OEM vs aftermarket: This is an OEM Cub Cadet part, so it’s a direct bolt-on replacement. Aftermarket yokes may vary in material thickness or bearing quality.

Key Things to Know

• Quality: Cast iron construction with a yellow powder coat – durable but heavy. Expect long life under normal residential or light commercial use.
• Installation difficulty: Moderate. Requires removing the old yoke, wheel, and spindle hardware. You’ll need a socket set, a hammer (to tap out the old spindle), and possibly a puller if rusted.
• Common gotchas: The spindle bolt (not included) can seize – soak with penetrating oil before removal. Also, the yoke’s grease fitting may be pre-installed; ensure you grease it after installation to prevent premature wear.
• Single review: Only one rating (5.0), so limited real-world feedback. Price is high for a yoke – consider if a cheaper aftermarket alternative fits your budget and model.

Should You Buy It

Buy this if you own a Cub Cadet Ultima ZTS1, ZTS2, or KH Fab mower and need a direct OEM replacement for a worn or bent front caster yoke. It’s a solid, long-lasting part but expensive. If you have a different Cub Cadet series or want to save money, measure first and check aftermarket options.