Fontaine H7 Heavy-Duty Fifth Wheel - Truck Equipment Atlas

Quick Facts

Manufacturer: Fontaine Fifth Wheel
Product Series: H7
Product Type: Extra-heavy and severe-duty fifth wheel
Top-Plate Construction: Steel-reinforced cast housing
Duty Classification: Extra-heavy to severe-duty on- and off-highway service
AWB Maximum Vertical Load: 62,500 pounds
AWB Maximum Drawbar Pull: 150,000 pounds
AWX and PS5 Maximum Vertical Load: 70,000 pounds
AWX and PS5 Maximum Drawbar Pull: 200,000 pounds
Kingpin Compatibility: Standard 2-inch SAE kingpin
Locking System: Enhanced self-adjusting Fontaine No-Slack mechanism
Mounting Options: Sliding, stationary, convertible tilt/no-tilt, and blocked no-tilt configurations
Primary Applications: Heavy haul, construction, mining, logging, frameless dumps, vocational trucks, and severe off-highway operations
Production Status: Current heavy- and severe-duty Fontaine product

Overview

The Fontaine H7 Heavy-Duty Fifth Wheel is an extra-heavy and severe-duty coupling system designed for demanding on-highway, vocational, and off-highway tractor-trailer applications. It combines Fontaine’s self-adjusting No-Slack locking technology with a reinforced cast top-plate housing.

The H7 is available with multiple mounting systems that affect its capacity and function. AWB air-slide assemblies support applications requiring fifth-wheel repositioning, while higher-capacity AWX and PS5 configurations are available for demanding heavy-haul service.

Blocked and convertible no-tilt configurations can support frameless dump applications that require the fifth wheel to remain rigid rather than pivoting normally. Because capacity and permitted operation depend on the selected mounting system, the complete H7 assembly must be identified before installation, operation, or parts ordering.

Key Characteristics

Steel-reinforced cast top-plate housing
Extra-heavy and severe-duty construction
Self-adjusting No-Slack locking mechanism
Positive secondary lock
Standard 2-inch kingpin compatibility
Mount-dependent load ratings
Sliding and stationary mounting options
Approved on- and off-highway applications
Blocked no-tilt configurations
Convertible tilt/no-tilt mounting systems
Compatible with frameless dump applications when correctly configured
Shared service components with other Fontaine No-Slack models

Major Components

Steel-reinforced cast top plate
Fifth-wheel throat
Enhanced self-adjusting lock
Wedge and wedge-stop rod
Locking trigger
Positive secondary lock
H7 operating handle and pull handle
Release linkage
Pivot pins and bushings
Mounting brackets
Slider rails and locking wedges when equipped
No-tilt blocks or conversion components when equipped
Mounting plate and structural reinforcement
Lubrication points

Coupling Type and Design

The H7 is a heavy-duty fifth-wheel coupling designed for a standard 2-inch SAE kingpin. In its normal tilting configuration, the top plate pivots forward and rearward to accommodate tractor-trailer articulation.

The reinforced cast housing provides additional capacity for heavy and severe-duty service. Fontaine’s No-Slack mechanism automatically adjusts around the kingpin as normal wear occurs, helping reduce movement and impact between the tractor and trailer.

When paired with an approved blocked or no-tilt mounting system, the fifth wheel can be prevented from pivoting for specific frameless dump-trailer applications. No-tilt operation must not be used with a conventional trailer that requires normal fifth-wheel articulation.

How the Coupling System Works

As the tractor backs beneath the trailer, the kingpin enters the fifth-wheel throat and activates the locking trigger. The primary lock closes around the kingpin, while the positive secondary lock helps prevent unintended release.

The No-Slack mechanism automatically compensates for normal wear within its approved service range. This helps reduce:

Tractor-trailer chucking
Coupling noise
Impact loading
Kingpin-to-lock movement
Accelerated component wear

The fifth wheel transfers the trailer’s vertical load and pulling forces into the mounting system and tractor frame. Mounting-system selection determines how much load the complete assembly can safely carry.

Position and Function Within the Vehicle

The H7 mounts above the tractor’s rear frame and axle group. It forms the primary structural connection between the tractor and a compatible semitrailer.

Its primary functions are to:

Support the front of the semitrailer
Capture and retain the trailer kingpin
Transfer pulling and braking forces
Permit articulation when used in tilting mode
Provide rigid support in approved no-tilt applications
Distribute trailer weight through the tractor frame and axles
Control movement between the tractor and trailer

Common Specifications

Top-Plate Construction: Steel-reinforced cast housing
AWB Maximum Vertical Load: 62,500 pounds
AWB Maximum Drawbar Pull: 150,000 pounds
AWX Maximum Vertical Load: 70,000 pounds
AWX Maximum Drawbar Pull: 200,000 pounds
PS5 Maximum Vertical Load: 70,000 pounds
PS5 Maximum Drawbar Pull: 200,000 pounds
Kingpin Size: Standard 2-inch SAE kingpin
Locking System: Enhanced self-adjusting Fontaine No-Slack lock
Secondary Lock: Positive mechanical secondary lock
Mounting Options: AWB, blocked AWB, AWX, PS5, blocked PS5, PMH, PMX, HDS, and HDI configurations where approved
Articulation: Standard tilting or approved no-tilt configuration
Application Range: Extra-heavy and severe-duty on- and off-highway service

Capacity, gross combination weight, mounting height, slide travel, assembly weight, and permitted application depend on the complete H7 mounting configuration. Confirm all specifications using the full assembly number and current Fontaine application guide.

Load Ratings and Operating Capacity

The H7’s ratings depend directly on its mounting system. Fontaine rates AWB configurations for 62,500 pounds of maximum vertical load and 150,000 pounds of maximum drawbar pull.

Approved AWX and PS5 configurations increase capacity to 70,000 pounds of maximum vertical load and 200,000 pounds of maximum drawbar pull.

The highest top-plate rating cannot be applied to a lower-rated mounting system. Actual vehicle capacity remains limited by the lowest-rated component, including:

Fifth-wheel mounting system
Tractor frame
Axles and suspension
Tires and wheels
Trailer kingpin
Trailer upper coupler
Trailer structure
Certified vehicle ratings

Articulation and Oscillation

In a standard tilting configuration, the H7 pivots forward and rearward to accommodate normal tractor-trailer movement over road grades, ramps, and uneven surfaces.

The H7 is not a fully oscillating fifth wheel and does not provide unrestricted side-to-side articulation. Operations requiring full lateral oscillation may need a different coupling design.

In an approved no-tilt configuration, the top plate is prevented from pivoting. This arrangement supports frameless dump trailers that articulate through their rear connection during unloading.

Sliding and Adjustment System

AWB, AWX, HDS, and HDI sliding configurations allow the fifth wheel to move forward or rearward along the tractor frame. Repositioning the fifth wheel can change:

Steering-axle loading
Drive-axle loading
Tractor-to-trailer clearance
Trailer swing clearance
Landing-gear clearance
Overall vehicle weight distribution

Slide travel, adjustment increments, frame attachment, and capacity depend on the selected mounting system. Every slider lock must be fully engaged and inspected before road operation.

Release and Locking Mechanism

The enhanced No-Slack lock automatically adjusts around the trailer kingpin to reduce free movement. A locking trigger initiates coupling, while the secondary lock helps prevent accidental release.

The H7 uses model-specific operating-handle and pull-handle components. Although it shares many service kits with Fontaine 6000 and 7000 fifth wheels, H7 handle components should not be assumed interchangeable.

Correct coupling must always be confirmed through a controlled pull test and direct visual inspection of the lock around the kingpin.

Air and Electronic Controls

Standard side-release H7 configurations use a mechanical operating handle and do not require electronic controls.

Air-slide configurations require:

A compatible tractor air supply
Protected air lines and fittings
A slide-control valve
A pneumatic cylinder
Mechanical linkage to the slide-locking wedges

Control availability differs among H7 assemblies. The full model number must be checked before assuming that an air-release or electronic option is available.

Mounting and Installation

The H7 must be installed using a Fontaine-approved mounting system and procedures appropriate for its capacity, tractor frame, and operating application.

Installation must provide:

Adequate tractor-frame strength
Correct mounting-plate reinforcement
Approved mounting fasteners
Correct fifth-wheel height
Required trailer swing clearance
Landing-gear and tire clearance
Correct slide travel and stop locations
Protected air-line routing when equipped
Correct tilt or no-tilt configuration

No-tilt installations require particular attention because incorrect use can transfer damaging forces into a conventional trailer or tractor frame.

Vehicle Frame and Mounting Compatibility

Compatibility depends on:

Tractor manufacturer and model
Frame width and rail construction
Frame reinforcement
Rear-axle arrangement
Suspension configuration
Required fifth-wheel height
Available mounting length
Required slider travel
Trailer swing and landing-gear clearance
Intended on- or off-highway duty
Required tilt or no-tilt operation

The complete mounting system—not the top plate alone—determines the assembly’s approved capacity and application range.

Mating Component and Trailer Compatibility

The H7 must be paired with an approved 2-inch SAE kingpin and compatible trailer upper-coupler structure.

Compatibility checks should include:

Kingpin size, profile, and wear
Upper-coupler flatness and structural condition
Trailer load rating
Trailer center of gravity
Trailer swing clearance
Landing-gear clearance
Required articulation
Suitability for no-tilt operation when applicable

A conventional semitrailer that depends on fifth-wheel articulation must not be coupled to an H7 locked in no-tilt mode.

Common Applications

Heavy-haul tractors
Construction tractors
Mining and quarry vehicles
Logging tractors
Oilfield-service vehicles
Frameless dump trailers with approved no-tilt assemblies
Heavy vocational tractors
On- and off-highway severe-duty operations
Specialized industrial transport

Advantages

Up to 70,000 pounds of vertical capacity with approved mounts
Up to 200,000 pounds of drawbar-pull capacity with approved mounts
Steel-reinforced cast housing
Self-adjusting No-Slack lock
Reduced kingpin-to-lock movement
Sliding and stationary mounting choices
Approved severe-duty on- and off-highway applications
Convertible and blocked no-tilt options
Support for approved frameless dump applications
Established parts and rebuild support

Limitations or Considerations

Capacity varies by mounting system
Higher-capacity top-plate ratings cannot be applied to lower-rated mounts
Heavy construction adds tractor weight
Requires regular lubrication and inspection
Sliding systems add maintenance points
No-tilt operation is only appropriate for specific trailers
Does not provide full side-to-side oscillation
Off-highway service may require shorter maintenance intervals
Does not increase the tractor’s certified ratings
Some configurations may only be available as first-fit equipment

Driver and Operator Experience

The self-adjusting lock helps reduce chucking and impact between the tractor and trailer. Sliding configurations allow drivers to reposition the fifth wheel for axle-weight and clearance adjustments.

Drivers using a no-tilt H7 must understand that the coupling will not pivot like a conventional fifth wheel. The tractor and trailer must be correctly aligned, and the configuration must only be used with an approved trailer.

Coupling and Uncoupling Procedure

Before coupling:

Inspect and lubricate the top plate
Confirm the locking mechanism is open
Inspect the trailer kingpin and upper coupler
Verify the correct trailer height
Confirm the mounting system is secure
Verify the correct tilt or no-tilt configuration

After coupling:

Perform a controlled pull test
Visually inspect the lock around the kingpin
Confirm the secondary lock is engaged
Verify there is no gap between the mating plates
Confirm slider locks are engaged when equipped
Connect and inspect air and electrical lines
Raise and secure the trailer landing gear

These steps provide a general overview and do not replace Fontaine instructions or fleet safety procedures.

Inspection and Wear Points

Lock and kingpin contact surfaces
Wedge and wedge-stop rod
Locking trigger
Positive secondary lock
H7 operating and pull handles
Top-plate surface and throat
Pivot pins and bushings
Mounting brackets and reinforcement
Slider rails, wedges, stops, and locks
No-tilt blocks and conversion components
Air lines and slide actuator
Trailer kingpin and upper coupler
Tractor frame and mounting fasteners

Lubrication Requirements

The top-plate surface, locking mechanism, wedge, pivot points, bracket contact areas, and applicable slider components require the manufacturer-specified lubricant and service intervals.

Severe-duty conditions that may require more frequent cleaning and lubrication include:

Mud and abrasive dust
Mining and quarry service
Logging operations
Water and road-salt exposure
Cold-weather operation
Frequent coupling and uncoupling
Heavy off-highway loads

Maintenance and Ownership Notes

Routine H7 maintenance should include:

Cleaning and lubricating the top plate
Inspecting the primary and secondary locks
Checking wedge-stop rod adjustment
Measuring kingpin wear
Inspecting H7-specific handle components
Checking pivot pins and bushings
Inspecting mounting brackets and fasteners
Checking slider rails and locking wedges
Inspecting no-tilt components when equipped
Testing pneumatic slide controls
Checking for cracks, distortion, and corrosion

Off-highway and severe-duty vehicles should be inspected more frequently than vehicles operating primarily on paved highways.

Common Coupling Problems

High coupling: Incorrect trailer height allows the kingpin to pass above the lock instead of entering through the throat.
Failure to lock: Dirt, damage, binding, poor lubrication, incorrect trailer height, or worn components may prevent engagement.
Difficult release: Pressure against the lock, damaged linkage, corrosion, contamination, or incorrect adjustment may restrict the handle.
Excessive kingpin movement: A worn kingpin, lock, wedge, or incorrectly adjusted wedge-stop rod may create excessive slack.
Slider will not move: Low air pressure, damaged lines, corrosion, contaminated rails, or tractor-trailer binding may prevent adjustment.
Slider locks will not engage: Misalignment, worn wedges, contamination, or damaged linkage may prevent full engagement.
Incorrect no-tilt operation: Missing, damaged, or improperly installed blocking components may allow unwanted movement or transmit improper loads.
Structural cracking: Overloading, loose mounting hardware, severe impacts, frame flex, or improper installation can damage the mount or tractor frame.

Safety and Service Precautions

Never rely on handle position alone to confirm coupling. Before moving the vehicle:

Perform a controlled pull test
Inspect the lock around the kingpin
Confirm the secondary lock is engaged
Verify there is no gap between the mating plates
Confirm all slider locks are engaged
Verify correct tilt or no-tilt operation

Never use no-tilt mode with a trailer that requires normal fifth-wheel articulation. Never weld, heat, grind, drill, straighten, or modify structural parts unless specifically permitted by Fontaine.

Identification Information

Record the following information before ordering parts or a replacement assembly:

Fontaine H7 model designation
Complete assembly number
Top-plate part number
Nine-digit serial number
Mounting-system model
Mounting height
Slider travel
Side-release or other release configuration
Tilt, convertible, or blocked no-tilt configuration
Vehicle identification number
Kingpin size and condition

Fontaine identifies the installed height within the complete model number. The serial number is typically engraved on the right side of the fifth-wheel skirt.

Buying Considerations

Determine the required vertical-load capacity
Confirm the required drawbar-pull rating
Verify gross combination weight requirements
Select the correct mounting system
Choose sliding or stationary mounting
Determine whether no-tilt capability is required
Confirm mounting height and slider travel
Verify tractor-frame strength
Check trailer swing and landing-gear clearance
Confirm kingpin and upper-coupler compatibility
Review replacement-parts availability
Use the current Fontaine application guide

Variants and Configurations

H7 configurations may include:

AWB air-slide assembly
Blocked AWB no-tilt air-slide assembly
AWX heavy-duty sliding assembly
PS5 reinforced stationary plate mount
Blocked PS5 no-tilt stationary mount
PMH convertible tilt/no-tilt stationary mount
PMX convertible tilt/no-tilt stationary mount
HDS outboard sliding mount
HDI inboard sliding mount
Different mounting heights and slide travels

Availability and capacity vary. Certain HDI and NHDI configurations may be limited to original-equipment or first-fit installations.

Comparison to Similar Equipment

Compared with the Fontaine No-Slack 7000 Fifth Wheel, the H7 supports higher-capacity and more severe-duty applications.

Compared with the Fontaine No-Slack 7000CC Clean Connect Fifth Wheel, the H7 emphasizes severe-duty strength rather than a grease-free top-plate surface.

Compared with the Holland FW70 Heavy-Duty Fifth Wheel, the H7 uses Fontaine’s self-adjusting No-Slack lock and Fontaine-specific mounting systems.

Compared with the Holland FW2080 Fully Oscillating Fifth Wheel, the H7 does not provide full side-to-side oscillation.

Best Fit For

Extra-heavy and severe-duty tractor applications
Heavy-haul fleets
Construction and mining operations
Logging and oilfield service
Approved off-highway applications
Frameless dump operations requiring no-tilt capability
Applications requiring up to 70,000 pounds of vertical capacity
Fleets wanting Fontaine No-Slack technology in a reinforced housing

Related Vehicle and Trailer Types

Related Truck and Trailer Models

Related Coupling Types

Related Coupling Products

Related Equipment Systems

Related Guides

Regulatory and Compliance Notes

The fifth wheel, mounting system, kingpin, upper coupler, tractor, and trailer must comply with applicable commercial-vehicle requirements.

The H7’s mechanical ratings do not override:

Gross axle weight ratings
Gross vehicle weight ratings
Gross combination weight ratings
Frame and suspension ratings
Tire and wheel ratings
Kingpin and upper-coupler ratings
Permit and road-weight restrictions

Blocked no-tilt configurations must only be used in approved applications and installed according to Fontaine and vehicle-manufacturer requirements.

Real World Operating Notes

The H7’s final capacity is determined by its mount. An H7 top plate installed on an AWB mount does not receive the higher AWX or PS5 rating.

Vehicles operating in mud, dust, mining sites, logging roads, or construction areas should receive more frequent cleaning and inspection. Abrasive contamination can accelerate wear in the lock, pivots, and slider system.

When a slider is repositioned, drivers should verify lock engagement and confirm axle weights on a certified scale. No-tilt users must confirm the configuration is correct before every trailer connection.

Frequently Asked Questions

What is the Fontaine H7?

It is a steel-reinforced cast fifth wheel designed for extra-heavy and severe-duty on- and off-highway applications.

What is the H7’s maximum vertical-load rating?

AWB configurations are rated for 62,500 pounds. Approved AWX and PS5 configurations are rated for up to 70,000 pounds.

What is its maximum drawbar-pull rating?

AWB configurations are rated for 150,000 pounds. Approved AWX and PS5 configurations are rated for up to 200,000 pounds.

Can the H7 be installed on a slider?

Yes. Fontaine offers approved sliding and stationary mounting configurations.

Can the H7 be used with a frameless dump trailer?

Yes, when installed in an approved blocked or no-tilt configuration designed for that application.

Can no-tilt mode be used with a conventional semitrailer?

No. A trailer that depends on normal fifth-wheel articulation must not be operated with the fifth wheel rigidly blocked.

Does the H7 use No-Slack technology?

Yes. Its lock automatically adjusts around the kingpin as normal wear occurs within approved service limits.

Are all Fontaine No-Slack parts interchangeable?

No. The H7 shares many service components with other No-Slack models, but it uses H7-specific operating-handle and pull-handle parts.

How are the correct replacement parts identified?

Use the complete assembly number, H7 top-plate number, serial number, mounting system, installed height, slide travel, and tilt or no-tilt configuration.

Availability and Where to Find

Fontaine H7 complete assemblies, replacement top plates, mounts, rebuild kits, locks, handles, pins, bushings, and no-tilt components may be available through Fontaine distributors, commercial-truck dealers, heavy-haul equipment installers, and heavy-duty parts suppliers.

Availability depends on required capacity, mounting height, slide travel, frame attachment, tilt or no-tilt operation, and complete assembly number.

Current product information is available through the official Fontaine H7 product page. Technical documents and service information are available through the Fontaine Fifth Wheel literature library.

Support Trucking Families

Truck Equipment Atlas supports the mission of Grey Cross, a nonprofit dedicated to helping families of truck drivers who lose their lives while on the road. As the site grows, part of its mission is to bring awareness and support to these families.

Podcast or Video Section

Learn More Through Audio and Video

Truck Equipment Atlas will continue expanding with podcast episodes, interviews, and equipment breakdowns to help drivers and fleets better understand trucks and equipment.

Follow the Growth of Truck Equipment Atlas

Truck Equipment Atlas continues to expand with new truck profiles, trailer coverage, diesel engine pages, equipment system resources, manufacturer information, and educational guides.

Visit our Site Updates page to explore recent additions, project milestones, and upcoming resources as we continue building one of the industry’s growing commercial trucking equipment reference libraries.

View the Latest Site Updates: Truck Equipment Atlas Site Updates