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

Heavy-duty upgrade: Covers the 4.2–5.0 ton class, with precision casting + alloy steel reinforcement for the bridge body, improving torsional rigidity by 30% to meet the heavy-duty requirements of intercity/tourist buses.
Ultra-quiet operation: Spiral bevel gear grinding process + active noise reduction technology, with NVH optimization of 45% and driving noise ≤62dB.
All-around safety braking: Standard dual-circuit air brakes + EBS + ABS (5.0-ton models support hydraulic retarder), response time ≤0.15 seconds, braking efficiency improved by 20%.
Maintenance-free design: IP6K9K sealing + intelligent centralized lubrication, key components (bearings/gears) with a lifespan of 500,000 kilometers, maintenance intervals exceeding 10,000 kilometers.

Technical Specifications

Category:	Technical Parameters
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
Optional Information:	Maintenance-Free Hub Unit
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
DF451S	4500	Air brake/φ400×130、19.5″	2220 – 2342	7.50×19.5	245/70R19.5	8 – M20×1.5
DF501S	5000	Air brake/φ400×130、φ400×150、22.5″	2173 – 2521	8.25×22.5	11.00R22.5	10 – M20×1.5
DD502S	5000	Air brake/19.5″	2363	7.50×19.5	245/70R19.5	8 – M20×1.5
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Basic information of bus steering axle
Category	Technical Parameter	Basic Structure Form	I – beam
Rim Mounting Distance B (mm)	1886 – 2209	Kingpin Center Distance C (mm)	1646 – 1852.3
Spring Distance D (mm)	846 – 1020	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	Optional Information	Maintenance – free Hub Unit
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