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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.

  • Grasshopper SO37 — commercial: daily paid use and high acreage; 61-inch deck; gas powered
  • Wright Autonomous ZK 61 61G8 — commercial: daily paid use and high acreage; 61-inch deck; gas powered
What’s different? The 5 differences that matter most, from the published figures.
  1. SO37 uses a Vanguard engine; Autonomous ZK 61 61G8 uses a Briggs & Stratton engine. The engine maker builds the engine; the mower maker chooses the model, rating and fit, so the badge alone does not settle output or longevity.
  2. SO37 has a T6 Drive Transmission transmission; Autonomous ZK 61 61G8 has a Hydro transmission. The transmission grade tracks duty rating and speed. Grade names are each maker's own and are not comparable across brands.
  3. SO37 has a published top speed of 10.5 mph; Autonomous ZK 61 61G8 has a published top speed of 12.5 mph, a 2 mph difference. Top speed is the maker's maximum in transport. Mowing speed is lower and depends on grass, terrain and the deck.
  4. SO37 holds 13.5 gal (51.1 L) of fuel; Autonomous ZK 61 61G8 holds 15.5 gal (58.7 L) of fuel, a 2 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.
  5. SO37 has a 37 hp engine; Autonomous ZK 61 61G8 has a 40 hp engine, a 3 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.
1 more difference, calculated figures and what isn’t comparable

Other verified differences

  • SO37 weighs 1,250 lbs (567 kg); Autonomous ZK 61 61G8 weighs 1,310 lbs (594.2 kg), a 60 lbs difference.

Calculated by MowerFacts

  • SO37 works out to 5.2 acres/hour; Autonomous ZK 61 61G8 works out to 6.2 acres/hour, a 1.0 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

  • Blades: not published for SO37.
  • Deck Material: not published for SO37.
  • Deck Construction: not published for SO37.
  • Start Type: not published for SO37.
  • Cut height range: not published for SO37.
  • Price: Autonomous ZK 61 61G8 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.

Add another (2 more fit): every commercial mower · more Grasshopper · more Wright
Side-by-side specifications: Grasshopper SO37 vs Wright Autonomous ZK 61 61G8
Spec SO37
Grasshopper · Commercial
Autonomous ZK 61 61G8
Wright · Commercial
List price $13,365dealer quote
Engine
Power Source gas gas
Engine Make Vanguard Briggs & Stratton
Displacement 60.6 ci (993 cc) 60.6 ci (993 cc)
Engine Power 37 hp 40 hp
Cylinders 2 —
Engine Model — 61G8
Fuel Type Gasoline Gasoline
Start Type — Electric
Deck
Cutting Width 61 in (1549 mm) 61 in (1549 mm)
Blades — 3
Deck Material — 7 Gauge
Deck Construction — Floating-Mulch
Deck Gauge — 7
Min Cut Height — 1.5 in (38 mm)
Max Cut Height — 5.5 in (140 mm)
Drive
Transmission T6 Drive Transmission Hydro
Ground Speed 10.5 mph 12.5 mph
Reverse Speed — 7 mph
Dimensions
Weight 1250 lbs (567 kg) 1310 lbs (594.2 kg)
Fuel Capacity 13.5 gal (51.1 L) 15.5 gal (58.7 L)
Length — 70 in (1778 mm)

SO37: Specs verified against the retailer listing on Jun 6, 2026 — tommysmotorsportscrossville.com.

Autonomous ZK 61 61G8: Specs verified against the retailer listing on Jun 6, 2026 — barryspowerequipment.com.

Independent reference database. Specs compiled from manufacturer sources and normalized for comparison; verify with the manufacturer or dealer before purchase.

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