Compare Mowers
List prices are the manufacturer’s published figures, re-checked daily; they exclude tax, freight and dealer setup.
A side-by-side reference of each model's stated specifications. MowerFacts doesn’t give opinions: where a published, spec-derived rule can separate machines we mark a Data Pick and show the rule; here, read the values and decide what fits your needs.
Best suited for
What each model is built for, from its duty class and key specs. This is a neutral reference — MowerFacts does not rank one model above another.
- Kubota Z421KWNC-54 — commercial: daily paid use and high acreage; 54-inch deck; gas powered
- Spartan Spartan RZ-XD Blackout — commercial: daily paid use and high acreage; 54-inch deck; gas powered
What’s different? The 4 differences that matter most, from the published figures.
- Z421KWNC-54 holds 6.8 gal (25.7 L) of fuel; Spartan RZ-XD Blackout holds 9.5 gal (36 L) of fuel, a 2.7 gal difference. Tank size bounds how long a machine runs between stops. Consumption varies with engine, load and speed, so hours per tank are not fixed.
- Z421KWNC-54 has a published top speed of 10 mph; Spartan RZ-XD Blackout has a published top speed of 9 mph, a 1 mph difference. Top speed is the maker's maximum in transport. Mowing speed is lower and depends on grass, terrain and the deck.
- Z421KWNC-54 has a 24 hp engine; Spartan RZ-XD Blackout has a 25.5 hp engine, a 1.5 hp difference. Published horsepower is the maker's rating at a stated engine speed. It is a different measure from displacement, and two engines of equal rating can pull differently.
- Z421KWNC-54 weighs 870 lbs (394.6 kg); Spartan RZ-XD Blackout weighs 907 lbs (411.4 kg), a 37 lbs difference. Operating weight bears on trailer payload, ramps and soft turf. On its own it says nothing about build quality. What Z421KWNC-54's weight means for a trailer ›
calculated figures and what isn’t comparable
Calculated by MowerFacts
- Z421KWNC-54 works out to 4.4 acres/hour; Spartan RZ-XD Blackout works out to 3.9 acres/hour, a 0.4 acres/hour difference. Calculated by MowerFacts from deck width and the published top speed at 80% efficiency; it is not a manufacturer figure, and real mowing is slower.
Not comparable
- Displacement: not published for Spartan RZ-XD Blackout.
- Warranty: not published for Z421KWNC-54.
- Transmission: not published for Spartan RZ-XD Blackout.
- Fuel Type: not published for Spartan RZ-XD Blackout.
- Deck Construction: not published for Z421KWNC-54.
- Drive System: not published for Spartan RZ-XD Blackout.
- Cut height range: not published for Z421KWNC-54.
- Price: Z421KWNC-54 is dealer quote only.
Verified means each manufacturer publishes the figure. A bigger number is only a bigger number; nothing here says which machine is better. The full specification table is below.
Which is faster on your property? › Measure your lawn once and MowerFacts times all 2 against it.
| Spec | Z421KWNC-54 Kubota · Zero-Turn |
Spartan RZ-XD Blackout Spartan · Zero-Turn |
|---|---|---|
| List price | dealer quote | $10,799 |
| Engine | ||
| Power Source | gas | gas |
| Displacement | 44.3 ci (726 cc) | — |
| Engine Power | 24 hp | 25.5 hp |
| Engine Make | Kawasaki FS730V | Kawasaki |
| Fuel Type | Gasoline | — |
| Deck | ||
| Cutting Width | 54 in (1372 mm) | 54 in (1372 mm) |
| Min Cut Height | — | 1.5 in (38 mm) |
| Max Cut Height | — | 4.8 in (121 mm) |
| Deck Construction | — | 5" Deep, Reinforced 7 Gauge Full-Floating Deck |
| Drive | ||
| Transmission | Hydro-Gear Commercial ZT-3600 | — |
| Ground Speed | 10 mph | 9 mph |
| Drive Tire Size | 24 x 9.5 -14, LP | 24x12-12 Reaper |
| Drive System | Belt | — |
| Dimensions | ||
| Weight | 870 lbs (394.6 kg) | 907 lbs (411.4 kg) |
| Fuel Capacity | 6.8 gal (25.7 L) | 9.5 gal (36 L) |
| Length | — | 84 in (2134 mm) |
| Height | — | 75 in (1905 mm) |
| Commercial / Pro | ||
| Frame Construction | — | 1.5" by 3" Powder Coated Fusion-Bonded Solid Steel Bridge Frame |
| Seat Type | — | Blackout Dymetrol Seat with 360 Degree Floating Seat Platform |
| General | ||
| Warranty | — | 3 yr |
Where these models differ, explained
Z421KWNC-54: Specs verified against the manufacturer spec sheet on Jun 6, 2026 — kubotausa.com.
Spartan RZ-XD Blackout: Specs verified against the manufacturer spec sheet on Jun 6, 2026 — joinspartannation.com.
Independent reference database. Specs compiled from manufacturer sources and normalized for comparison; verify with the manufacturer or dealer before purchase.