SITRAK C7H: 130-Ton Heavy Haulage Tractor & MC13 Powertrain Engineering
SITRAK C7H – Chinese heavy haulage tractor engineered for 41 mph top speed and 130-ton towing capacity with MC13 540 hp power.
The SITRAK C7H is not a typical highway truck—it is a heavy haulage tractor engineered for one of the most demanding tasks in transportation: moving ultra-heavy loads that would crush conventional trucks. Developed by Sinotruk (China National Heavy Duty Truck Group), the C7H is designed to pull trailers carrying up to 130 tons (286,000 lbs) of cargo, from massive transformers to industrial machinery. With a top speed of 41 mph (66 km/h) and the powerful MC13 engine producing 540 hp and 2,500 Nm of torque, the C7H represents Chinese engineering at its most robust. This is the complete engineering breakdown of China's heavy haul champion.
1. Technical Overview
The SITRAK C7H ZZ5256V324HE1H is a heavy haulage tractor manufactured by Sinotruk (中国重汽), one of China's largest commercial vehicle manufacturers. Designed specifically for超重大件运输 (ultra-heavy component transport), the C7H features a reinforced chassis, dual-stage hub reduction axles, and a powertrain optimized for maximum tractive effort rather than speed. Unlike the Caterpillar 772 which is an off-highway dump truck, the C7H is a road-going tractor designed to pull specialized heavy haul trailers on public highways and industrial sites. Its primary mission: move loads that exceed 100 tons safely and reliably, often at speeds that would be considered slow by highway standards but are remarkable given the mass involved.
2. Top Speed & Velocity Profile
| Metric | Value |
|---|---|
| Top Speed (loaded) | 41 mph (66 km/h) |
| Cruising Speed (typical) | 30–35 mph (48–56 km/h) with heavy load |
| Trailer Tow Capacity | 130,000 kg (286,000 lbs) |
| Gross Combination Weight | ~155,000 kg (341,000 lbs) |
| Fuel Tank Capacity | 600 L (158 gallons) |
| Range (at full load) | ~500 miles (800 km) estimated |
3. Powertrain & Engine System
The C7H is powered by the MC13.54-50 engine, a 13-liter inline-6 diesel developed by Sinotruk in collaboration with MAN. This engine is designed specifically for heavy haul applications where low-end torque is critical.
- Engine: MC13.54-50 (12.8L inline-6, turbo-diesel, common rail)
- Power Output: 540 hp (397 kW) @ 1,900 rpm
- Torque: 2,500 Nm (1,844 lb-ft) @ 1,050–1,350 rpm
- Transmission: HW25712XSJ (12-speed manual with crawler gear)
- Clutch: Φ430 ceramic clutch for extreme torque loads
- Engine Brake: EVB (Exhaust Valve Brake) with 3-stage control
- Emissions: Euro 5 / China V standards
4. Chassis & Frame Engineering
The C7H's frame is the key to its 130-ton towing capacity. Unlike standard highway trucks, the heavy haul variant features a reinforced ladder frame with multiple layers of high-strength steel.
- Frame Rails: 8+8+8 mm thick (three layers), 300 mm section height
- Material: High-strength low-alloy (HSLA) steel, 700 MPa yield strength
- Crossmembers: Heavy-duty tubular crossmembers with gusset reinforcement
- Fifth Wheel: Heavy-duty sliding type with 3.5" kingpin capacity
- Front Axle: VOK-07 (7.5 ton capacity)
- Rear Axle: MCP23 dual-stage hub reduction (23 ton capacity each, total 46 tons)
5. Suspension & Braking
With a gross combination weight exceeding 150 tons, the C7H's suspension and braking systems are engineered for safety and stability.
- Front Suspension: 9-leaf parabolic springs with stabilizer bar
- Rear Suspension: 12-leaf springs with balancing beam for even load distribution
- Service Brakes: Dual-circuit air brakes with ABS
- Parking Brake: Spring-actuated, air-release on rear axles
- Auxiliary Brake: EVB exhaust brake with 300 kW retarding power
- Tire Size: 12.00R20 (18 PR) heavy-duty radial
⚙️ TECH INSIGHT: Dual-Stage Hub Reduction
The MCP23 rear axle in the SITRAK C7H uses dual-stage hub reduction, a technology critical for heavy haul applications. Unlike conventional single-reduction axles where the final drive is only in the differential, hub reduction places an additional gear reduction inside each wheel hub. This provides two key advantages: (1) it reduces the torque load on the differential and driveshaft, allowing them to be smaller and lighter, and (2) it increases ground clearance because the differential housing can be smaller. The final drive ratio options are 5.26 or 5.92, meaning the driveshaft turns 5.26 times for every wheel revolution. Combined with the 12-speed transmission's crawler gear (first gear ratio typically 14-16:1), the C7H can achieve a total reduction of over 90:1 in first gear. This allows the 2,500 Nm engine torque to be multiplied to over 225,000 Nm at the wheels—enough to move 130 tons from a dead stop on a steep grade. The hub reduction system is also more durable for heavy haul applications because the gear reduction happens close to the wheel, reducing stress on the axle shafts. This is the same technology found in heavy mining trucks like the Caterpillar 772, scaled for highway use.
6. Heavy Haulage Application
The C7H is specifically configured for超重大件运输 (ultra-heavy component transport), a specialized niche requiring permits, escorts, and meticulous planning.
- Typical Loads: Transformers (up to 400 tons), industrial machinery, wind turbine components, bridge sections
- Trailer Type: Multi-axle hydraulic modular trailers (up to 20+ axles)
- Permit Requirements: Oversize/overweight permits in all jurisdictions
- Escort Vehicles: Required for width/height clearance and traffic control
- Speed Restriction: Typically limited to 25-30 mph (40-48 km/h) with heavy loads
- Route Planning: Must avoid weak bridges, tight turns, and steep grades
7. Heavy Duty Speed Classification
According to the Speedo Science Land Speed Index, the SITRAK C7H occupies the Heavy Haul class, optimized for maximum towing capacity rather than outright speed.
| Class | Speed Range (mph) | Example Models |
|---|---|---|
| High-Speed Heavy | 45–60 mph | Caterpillar 772 |
| Heavy Haul | 30–45 mph | SITRAK C7H, Western Star 6900 |
| Ultra Heavy | <30 mph | HOVA Terminal Tractor, Komatsu D575A |
8. Technical Specifications
| Specification | Data |
|---|---|
| Manufacturer | Sinotruk (China National Heavy Duty Truck Group) |
| Model | C7H ZZ5256V324HE1H |
| Type | Heavy Haulage Tractor (6x4) |
| Engine | MC13.54-50 (12.8L inline-6 turbo-diesel) |
| Power | 540 hp (397 kW) @ 1,900 rpm |
| Torque | 2,500 Nm (1,844 lb-ft) @ 1,050–1,350 rpm |
| Transmission | HW25712XSJ (12-speed manual with crawler gear) |
| Top Speed | 41 mph (66 km/h) |
| Trailer Tow Capacity | 130,000 kg (286,000 lbs) |
| Gross Vehicle Weight | 25,000 kg (55,000 lbs) |
| Curb Weight | 10,900 kg (24,000 lbs) |
| Front Axle Capacity | 7.5 tons |
| Rear Axle Capacity (each) | 23 tons (dual-stage hub reduction) |
| Final Drive Ratio | 5.26 / 5.92 |
| Fuel Tank | 600 L (158 gallons) |
| Tire Size | 12.00R20 (18 PR) |
| Suspension (front) | 9-leaf parabolic springs |
| Suspension (rear) | 12-leaf springs with balancing beam |
| Frame Rails | 8+8+8 mm / 300 mm section |
9. Velocity Engineering Insight
At 41 mph with a 130-ton load, the SITRAK C7H's kinetic energy is approximately 42 megajoules—three times that of the Caterpillar 772 and enough to power a home for two weeks. Stopping this mass requires planning and skill; the combination of service brakes and exhaust brake must be used judiciously to avoid overheating.
The 12-speed transmission's crawler gear (first gear) provides a ratio of approximately 14:1, which, combined with the 5.92 rear axle ratio, gives a total reduction of 83:1. This allows the 540 hp engine to exert over 200,000 lb-ft of torque at the wheels—enough to start a 130-ton load on a 6% grade without slipping the clutch. The Φ430 ceramic clutch is designed to handle this torque without fading, using ceramic materials that resist heat better than organic friction materials.
The 8+8+8 mm frame rails are overbuilt by highway truck standards. A typical Class 8 highway truck uses 3/8" (9.5 mm) single-layer rails. The C7H's triple-layer construction provides three times the section modulus, resisting bending under the massive fifth wheel loads imposed by heavy haul trailers. The 300 mm frame height is also deeper than standard, further increasing rigidity.
According to the Speedo Science Land Speed Index, the C7H's 41 mph top speed places it in the Heavy Haul class, distinct from both the High-Speed Heavy class (45-60 mph) and Ultra Heavy class (<30 mph). This reflects its mission: not the fastest, but capable of pulling loads that would destroy lesser trucks.
10. Conclusion
The SITRAK C7H represents a different philosophy of heavy-duty engineering: maximum towing capacity over outright speed. Its 41 mph top speed, 130-ton tow rating, and reinforced chassis make it a specialist tool for one of the most demanding jobs in transportation.
In the Speedo Science Land Speed Index, the C7H occupies the Heavy Haul class, bridging the gap between high-speed heavy trucks like the Caterpillar 772 and ultra-heavy specialized equipment. Its dual-stage hub reduction axles, triple-layer frame, and ceramic clutch demonstrate that Chinese engineering has mastered the art of moving massive loads.
For heavy haul operators and logistics engineers, the C7H proves that speed is not the only metric—torque, traction, and structural integrity matter just as much when you're moving 130 tons. And with 540 hp and 2,500 Nm on tap, the C7H delivers where it counts: at the drawbar, pulling the loads that power modern civilization.
📌 RELATED LAND SPEED ARTICLES
→ Caterpillar 772: 49 mph Off-Highway Dump Truck & Cat C18 Engineering →
→ HOVA Terminal Tractor: 154,000 lbs Capacity for Port Operations →
→ Western Star 6900: Heavy Haul Truck Engineering →
Source: Sinotruk | China National Heavy Duty Truck Group | Heavy Lift & Project Forwarding International | Speedo Science Database
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