1. Global Matching Safety Standards
China National Standard GB/T 4330-2024 (Agricultural Trailer)
Applicable gross weight: 0.5t – 24t tractor full trailers.
Overall dimension limits:
Max total length: ≤ 12m.
Max width: ≤ 2.55m.
Max height: ≤ 4.0m.
Rear overhang: ≤ 55% of wheelbase, absolute ≤ 3500mm.
Tongue weight standard: 10%–15% of full loaded trailer GVWR.
Safe towing ratio: Tractor rated towing capacity ≥ 1.25× trailer total loaded weight.
International ISO Standards
ISO 5692-1: Agricultural tractor hitch ring & pin size unified specification.
ISO 7072: Three-point linkage mounting dimension standard.
Universal farm hitch: Pintle hook (38mm/50mm pin), standard ball hitch 50mm.
Core Matching Safety Rules
Never exceed 80% of tractor rated GCWR for field/hilly work.
Single axle: Flat ground only; tandem axle mandatory for slope/mud.
Hydraulic trailer brakes must match tractor hydraulic output pressure.
7-pin electrical connector standard for farm lighting & signal.
2. Horsepower ↔ Trailer Size & Load Matching Table (Farm Standard)
| Tractor HP | Axle Type | Rated Trailer Payload | Standard Overall Size (L×W×H) | Common Trailer Model |
|---|---|---|---|---|
| ≤30 HP | Single axle | 1.5–3 t | 4.0×1.74×2.15 m | 7CX-1.5 / 7CX-3 |
| 30–50 HP | Single/Tandem | 3–5 t | 5.85×2.2×2.6 m | 7CX-4 |
| 50–80 HP | Tandem axle | 5–8 t | 6.2×2.3×2.6 m | 7CX-5 |
| 80–120 HP | Tandem/Tridem | 8–15 t | 7.0–9.0×2.4×2.8 m | Heavy-duty dump/flatbed |
| ≥120 HP | Tridem axle | 15–24 t | ≤12.0×2.55×4.0 m | Large grain/livestock trailer |
3. Standard Farm Trailer Dimensions By Type
Flatbed Utility Trailer
Standard cabin size: 2.6×1.6×0.55m (3t) / 2.8×1.6×0.55m (4t).
Deck height: 0.8–1.0m; Wide agricultural tires for mud ground.
Dump Trailer (Grain/Manure/Soil)
Common size: 5.0×2.4×1.5m | Max load: 3–5t.
Hydraulic lifting stroke: 1.2–1.8m; Rear unloading only.
Livestock Trailer
Internal width: 2.2–2.4m; Partition height: 1.2–1.6m.
Non-slip floor + ventilation slots; GVWR 4–10t.
Grain Bulk Trailer
High side: 1.8–2.2m; Tarp sealed; Length 6–9m.
Axle: Tandem heavy-duty; Low center of gravity.
4. Hitch & Brake Matching Standard
Hitch Type Matching
Small tractor (<50HP): 50mm ball hitch.
Medium/large tractor (>50HP): 50mm pintle hook (farm standard, heavy load resistant).
Drawbar pin: Standard 25mm / 32mm unified size.
Brake System Matching
<1.5t: No brake allowed only flat field.
1.5–8t: Tractor synchronous hydraulic brake (mandatory).
8t / Highway use: Electric brake + 7-pin wiring harness.
5. Terrain Adaptation Size Standard
Flat farmland: Normal wheelbase, standard ground clearance.
Hilly rolling land: Short wheelbase tandem axle, ≥350mm ground clearance.
Muddy wet field: Extra-wide low-pressure agricultural tires, narrow body ≤2.3m width.
Rocky rough road: Reinforced chassis, long suspension travel trailer.
6. Quick Compliance Check List
Tractor GCWR ≥ Trailer GVWR + cargo weight.
Tongue weight within 10%–15% loaded weight.
Overall size comply with GB/T 4330 limit.
Hitch pin, brake pressure, circuit fully compatible.
Axle load balanced, no overweight single axle.
