What Is a Coiled Air Brake Hose?

A coiled air brake hose is used in commercial vehicle air brake systems to transmit compressed air between the tractor and trailer, allowing compressed air to be delivered to the trailer braking system.

Heavy-duty vehicles such as trucks, trailers, and buses commonly use air brake systems as their primary braking method. These systems typically consist of an air compressor, air reservoirs, control valves, brake components, and related piping components.

Compared with air brake tubing installed as fixed piping along the vehicle chassis, coiled air brake hoses are mainly used at the dynamic connection between the tractor and trailer. Since relative movement occurs when vehicles turn or when the distance between vehicles changes, the hose is typically formed into a spiral structure that allows it to extend and retract accordingly.

Installation Locations of Coiled Air Brake Hoses

• Between the tractor and trailer
• Semi-trailer connections
• Air brake connections for articulated vehicles

Structural Design of Coiled Air Brake Hose

Coiled air brake hoses are commonly made from nylon tubing and formed into a spiral structure to allow extension and retraction.

The basic construction typically includes:

• Air brake tubing
• Spiral hose structure
• End connection fittings

Standards for Coiled Air Brake Hose

Commercial vehicle coiled air brake hoses are commonly designed according to different market standards, mainly based on standards such as DIN 74323 and SAE J844.

DIN 74323 (European Market)

DIN 74323 is a commonly used European standard for coiled air brake hoses in commercial vehicles, mainly used in truck, bus, and trailer systems in Europe.

SAE J844 (North American Market)

SAE J844 is an air brake tubing standard established by the Society of Automotive Engineers (SAE), primarily used in truck and trailer systems in North America.

Comparison Between DIN 74323 and SAE J844

DOT FMVSS 106 and Air Brake Systems

In the North American market, commercial vehicle air brake systems are typically required to comply with DOT FMVSS 106 regulations.

DOT FMVSS 106 is a federal motor vehicle safety standard related to brake systems. It specifies performance, testing methods, and identification requirements for brake hoses and related components.

In commercial vehicle applications, the air brake hose assemblies used between the tractor and trailer must comply with the safety requirements specified by this regulation.

Further Reading

→ DOT Air Brake Fittings

→ Air Brake Tubing

→ DOT Brake Tubing and PU Air Hose Applications