DD391S | Steering axle
DD391S is F3.9 series high-performance I-beam steering axle with a rated load of 3900kg (next highest in the same series).
It is equipped with large-sized air brake system (φ400×130 brake drum, 19.5° rim) as standard, with fixed wheelbase of 2233mm to optimize the space layout, and a rim mounting distance of 1844mm for precise fitment.
The center distance of the main pin is 1662mm to strengthen the steering rigidity, with 6.25×22.5 rims and 295/80R22.5 wide base tires (ply reinforcement).
The steering angle of the outer wheel is up to 41° (the best in the same platform), and the air chamber interface is compatible with NPT1/4/Z1/4/M16×1.5 standards, which meets the demand for high stability and adaptability to complex working conditions of heavy-duty commercial vehicles.
DD391S Product Features
Heavy Load Upgrade: Flange-forged I-beam technology with load-bearing capacity ranging from 3.6 to 4.5 tons, suitable for heavy-duty scenarios such as mining and engineering.
Efficient Braking: Standard equipped with large Ø430mm air brake calipers, with optional ABS and automatic brake gap adjusters for fast braking response and low heat fade.
Structure Reinforcement: Wider wheelbase (1820-2020mm), reinforced axle housing + tapered roller bearings, enhancing torsional resistance and durability.
Intelligent Maintenance: Supports central lubrication systems (F4.5 series), extending maintenance intervals; optimized sealing of key components reduces failure rates.
Technical Specifications
| Category: | Steering axle |
| Platform: | DD391S |
| Basic Structure: | I – Beam |
| Rated Load (kg): | 3900 |
| Brake Structure/Specifications: | Air brake/φ400×130、19.5″ |
| Maximum External Width A (mm): | 2233 |
| Rim Installation Distance B (mm): | 1844 |
| Kingpin Center Distance C (mm): | 1662 |
| Spring Distance D (mm): | 820 – 851 |
| Front Axle Drop: | 100 + 21 |
| Kingpin Inclination/Wheel Camber: | 7° / 1° |
| Inner Wheel Steering Angle/Outer Wheel Steering Angle: | 41° |
| Rim: | 6.25×22.5 |
| Tire: | 295/80R22.5 |
| Wheel Bolts: | 8 – M22×1.5 |
| Wheel Bolt Circle E (mm): | φ275 |
| Wheel Toe (mm): | 2 – 4 |
| Air Chamber Interface Dimensions: | NP1/4 、Z1/4 、M1.6 × 1.5 |
| Lead Time: | 15 – 30 Working Days |
| Payment Terms: | T/T, L/C |
Model | Rated Load (kg) | Brake Structure Form/Specification | Maximum Overall Width A (mm) | Rim | Tire | Wheel Bolt |
| DD391S | 3900 | Air brake/φ400×130、 19.5″ | 2233 | 6.25×22.5 | 295/80R22.5 | 8 – M22×1.5 |
| DF451S | 4500 | Air brake/φ400×130、 19.5″ | 2220 – 2342 | 7.50×19.5 | 245/70R19.5 | 8 – M20×1.5 |
| DF361S | 3600 | Air brake/φ360×130、 φ400×130、19.5″ | 2220 – 2342 | 7.50×19.5 | 245/70R19.5 | 8 – M20×1.5 |
| ——END—— | ||||||
Basic information of truck steering axle | |||
| Category | Steering Axle | Basic Structure Form | I – beam |
| Rim Mounting Distance B (mm) | 1844 | Kingpin Center Distance C (mm) | 1662 |
| Spring Distance D (mm) | 820 – 851 | Front Axle Drop (mm) | 100 + 21 |
| Kingpin Inclination Angle/Wheel Camber Angle | 7°/1° | Inner Wheel Steering Angle/Outer Wheel Steering Angle | 41° |
| Wheel Bolt Distribution Circle E (mm) | φ275 | Wheel Toe – in (mm) | 2-4 |
| Air Chamber Interface Size | NPT1/4、 Z1/4、 M16×1.5 | ||
| ——END—— | |||

Note: All Above Data are Just for Reference, All Data Might Change Without Notices or Updates, Please Contact Our Sales Team to Confirm All Details Via WhatsApp or Email.

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