DF421S | Bus steering axle

The Dongfeng Dana Coach Axle DF421S is the top-of-the-line I-beam steering axle in the F4.2 series, with a rated load of 4200 kg (the highest in the entire series).
Standard equipment includes an air brake system (compatible with 19.5″ wheel rims), exclusively supporting the industry’s widest wheelbase adjustment range of 2205-2472 mm and the largest wheel rim mounting distance span of 1886-2209 mm (323 mm industry record);
The kingpin center distance is precisely controlled within a tolerance of 1646-1852.3 mm, and the 100 mm ultra-strong front axle drop significantly improves off-road performance; compatible with 245/70R19.5 wide-base tires and 7.50×19.5 rims, with an outer wheel steering angle of 41°, a bolt distribution circle of φ275 for reinforced load-bearing structure, and 8 M20×1.5 high-strength bolts + three-chamber interfaces (NPT1/4/Z1/4/M16×1.5) to meet the extreme operating conditions of special buses.
We provide full life cycle services for all customers, from design to power system supply, from installation to commissioning, from after-sales service training to spare parts supply, from trouble shooting to overhaul technical support.

DF421S Product Features

Superior load capacity: covering 2.7 to 4.2 tons, the bridge body is precision cast from high-strength steel, with 25% improved torsional resistance, suitable for long-distance/public transportation heavy-duty requirements.
Ultra-Quiet and Smooth: Features ground spiral bevel gears and adaptive noise-reduction design, with NVH performance optimized by 40%, and driving noise ≤65dB.
Intelligent Braking Safety: Standard across the range with disc brakes + EBS electronic braking + ABS (F4.2 supports dual-circuit air brakes), response time ≤0.2 seconds, braking distance reduced by 15%.
Extended Maintenance Intervals: IP6K9K-rated sealing + centralized lubrication system, key components designed for maintenance-free operation, maintenance intervals up to 8,000 km, reducing operational costs by 30%.

Technical Specifications

Category:	Steering axle
Platform:	DF421S
Basic Structure:	I-beam
Rated Load (kg):	4200
Brake Structure/Specifications:	Air brake/φ360×130、φ400×130、19.5″
Maximum External Width A (mm):	2205-2472
Rim Installation Distance B (mm):	1886-1975
Kingpin Center Distance C (mm):	1646-1852.3
Spring Distance D (mm):	846-1020
Front Axle Drop (mm):	100
Kingpin Inclination/Wheel Camber:	7°/1°
Inner Wheel Steering Angle/Outer Wheel Steering Angle:	41°
Rim:	7.50×19.5
Tire:	245/70R19.5
Wheel Bolts:	8-M20×1.5
Wheel Bolt Circle E (mm):	φ275
Wheel Toe (mm):	1 – 3
Air Chamber Interface Dimensions:	NPT1/4、Z1/4、M16×1.5
Lead Time:	15 – 30 Working Days
Payment Terms:	T/T, L/C

coming soon

Model	Rated Load (Kg)	Brake Structure Form/Specification	Maximum Overall Width A (mm)	Rim	Tire	Wheel Bolt
DF421S	4200	Air brake/φ360×130、φ400×130、19.5″	2205 – 2472	7.50×19.5	245/70R19.5	8 – M20×1.5
DF302S	3000	Air brake/φ310×120、φ310×130、17.5″	2053.5 – 2209	6.00×17.5	215/75R17.5	6 – M18×1.5、6 – M20×1.5
DF351S	3500	Air brake/φ310×130、φ400×130、17.5″/19.5″	2119 – 2290	6.00×17.5	215/75R17.5	6 – M18×1.5、6 – 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
DF271S	2700	Air brake/φ310×100、17.5″	1754 – 2468	6.00×17.5	215/75R17.5	6 – M18×1.5、6 – M20×1.5
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Basic information of bus steering axle
Category	Steering Axle	Basic Structure Form	I – beam
Rim Mounting Distance B (mm)	1886 – 2209	Kingpin Center Distance C (mm)	1646 – 1852.3
Spring Distance D (mm)	806 – 900	Front Axle Drop (mm)	100
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)	1-3
Air Chamber Interface Size	NPT1/4、Z1/4、M16×1.5
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