(2) Pneumatic Tire Assemblies 11x4.00-5 Fits Kubota Z100 K3011-18020 K3011-18030

What It Is

This is a pair of pneumatic (air-filled) tire assemblies sized 11x4.00-5, designed as direct replacements for Kubota Z100 series zero-turn mowers and other machines using the same wheel hub pattern. They are aftermarket replacements for OEM part numbers K3011-18020 (left) and K3011-18030 (right).

Fitment & Compatibility

Before buying, confirm the following:

• Model fit: Designed for Kubota Z100 series (Z125S, Z125SK, Z125KH, etc.). Also fits some Z200, Z300, and Z400 models with the same 5-inch wheel bolt pattern and tire size.
• Measurements: 11-inch tire outer diameter, 4.00-inch tire width, 5-inch rim diameter.
• Hub/bolt pattern: Verify your mower uses a 4-bolt, 4-inch center-to-center pattern (common on Kubota zero-turns). Measure center-to-center on two opposite bolts.
• OEM cross-reference: K3011-18020, K3011-18030. These are aftermarket—not OEM Kubota parts—but match dimensions and load rating.
• Load rating: Check your mower’s front axle weight (usually 250-400 lbs per tire). These tires handle typical zero-turn front loads.

Key Things to Know

• Installation: Moderate difficulty. You’ll need a jack, socket set, and possibly a tire iron to remove old assemblies. No special tools for the tire itself—just bolt on.
• Tire pressure: Run at 20-25 PSI max. Overinflating reduces traction and ride comfort; underinflating risks rim damage.
• Valve stem orientation: Some users report stems can be slightly off-center on aftermarket rims. Check clearance against the mower frame before tightening.
• Tread pattern: Smooth or light-rib tread—not aggressive. Best for flat turf, not steep slopes or mud.

Should You Buy It

Buy if your Kubota Z100 front tires are worn, dry-rotted, or have a leak you can’t patch. They’re a solid value vs. OEM parts (typically $100+ each) and have good reviews for fit and durability. Avoid if you need aggressive traction on rough terrain—these are primarily smooth-turf tires.