Hendrickson VANTRAAX

Quick Facts

  • Manufacturer: Hendrickson
  • Product Type: Integrated sliding tandem trailer suspension system
  • Primary Model: VANTRAAX HKANT 40K
  • Suspension Design: Air suspension with sliding subframe, integrated axles, and brakes
  • System Capacity: 40,000 pounds for the current listed HKANT configuration
  • Axle Arrangement: Tandem trailer axles
  • Standard Axle Spacing: 49 inches on the listed HKANT 40K
  • Available Slider-Box Widths: 42 and 48 inches
  • Available Ride Heights: 16 and 17 inches on the listed HKANT 40K
  • Base Model Weight: Approximately 1,405 pounds
  • Primary Applications: Dry van, refrigerated, and specialty van trailers
  • Optional Brake Equipment: Air disc brakes

Overview

Hendrickson VANTRAAX is an integrated sliding tandem trailer suspension system developed primarily for dry-freight, refrigerated, and specialty van trailers. It combines Hendrickson’s slider-box technology with INTRAAX integrated air suspensions, axles, and brake assemblies.

The sliding subframe allows the tandem axle group to move forward or rearward beneath the trailer. This helps fleets adjust axle loading, comply with bridge and axle-weight requirements, and accommodate different cargo distributions.

The current listed VANTRAAX HKANT 40K combines a lightweight K-2-style slider structure with tandem INTRAAX suspension and axle assemblies. The complete system is rated at 40,000 pounds and is available with selected brake, wheel-end, damping, and tire-management options.

Key Characteristics

  • Integrated tandem trailer slider system
  • Combines slider frame, air suspensions, axles, and brakes
  • Designed primarily for dry van and refrigerated trailers
  • 40,000-pound system capacity on the listed HKANT model
  • 49-inch tandem axle spacing
  • 42- or 48-inch slider-box widths
  • 16- or 17-inch suspension ride heights
  • QUIK-ALIGN axle-alignment system
  • Large-diameter axle technology on applicable models
  • Lightweight construction for increased payload potential
  • Available air disc brakes
  • Standard manual pin-pull mechanism in the published base configuration
  • Optional ZMD damping technology on selected models
  • Designed for low maintenance and long service life

Major Components

  • Sliding subframe or slider box
  • Tandem INTRAAX suspension assemblies
  • Integrated trailer axles
  • Rigid trailing beams
  • Air springs
  • Shock absorbers or ZMD air springs and down stops
  • Frame hangers
  • Pivot bushings
  • QUIK-ALIGN eccentric and concentric collars
  • Slider rails and crossmembers
  • Locking pins
  • Pin springs and linkage
  • Manual pin-pull mechanism
  • Axle connections
  • Brake chambers
  • Drum- or air-disc-brake assemblies
  • ABS sensors and wiring
  • Wheel hubs, bearings, and seals
  • Height-control valve and linkage
  • Air lines, reservoirs, valves, and fittings

How the Suspension System Works

VANTRAAX uses air springs to support the rear of the trailer above the tandem axle group. The springs compress and expand as the trailer passes over road irregularities, reducing shock transferred into the frame and cargo.

Each integrated suspension uses rigid trailing beams and pivot bushings to control axle movement. Shock absorbers or optional ZMD technology damp repeated suspension movement.

The tandem suspensions are attached to a sliding subframe. When the locking pins are retracted, the complete axle and suspension group can move forward or rearward along the trailer’s slider rails.

Once the desired position is reached, the locking pins engage matching holes in the trailer rails. This locks the tandem beneath the trailer and establishes the axle-group position for operation.

Suspension Position and Function

VANTRAAX is installed beneath the rear portion of a van-style commercial trailer. It serves as the trailer’s tandem axle group while also providing the sliding adjustment required for weight distribution.

The system performs several functions:

  • Supports the rear portion of the trailer and cargo
  • Connects the tandem axles to the trailer structure
  • Maintains the specified suspension ride height
  • Absorbs bumps and road irregularities
  • Allows the tandem group to move forward or rearward
  • Helps adjust weight between the tractor drives and trailer tandems
  • Provides mounting for brakes and wheel ends
  • Maintains axle alignment
  • Helps protect cargo and trailer structure from road shock
  • Locks the axle group securely in its selected position

Common Specifications

  • Model: VANTRAAX HKANT 40K
  • Axle Arrangement: Tandem
  • Axle Spacing: 49 inches
  • System Capacity: 40,000 pounds
  • Axle Type: Hendrickson large-diameter axle in the listed configuration
  • Slider-Box Widths: 42 or 48 inches
  • Suspension Ride Heights: 16 or 17 inches
  • Base Model Weight: Approximately 1,405 pounds
  • Base Weight Includes: Slider, tandem suspensions, axles, foundation brakes, and manual pin-pull mechanism for the 48-inch-wide slider box
  • Brake Availability: Drum brakes with air disc brakes available as an option
  • Primary Applications: Dry-freight, refrigerated, and specialty van trailers
  • Total System Height Calculation: Suspension ride height plus approximately 8.5 inches for listed HKANT, HKAT, and HKAL slider-box configurations

The system capacity includes the slider box, suspensions, and axles. Brakes, wheels, and tires are rated separately.

Capacity, Ride Height, and Axle Travel

The listed VANTRAAX HKANT has a 40,000-pound total system capacity. This rating covers the slider structure, suspension assemblies, and axles but does not automatically establish the capacity of the brakes, tires, wheels, hubs, bearings, or trailer frame.

Available suspension ride heights are 16 and 17 inches on the listed HKANT 40K. To estimate the total installed system height, Hendrickson directs users to add approximately 8.5 inches for the slider-box structure.

Correct ride height is essential for axle-load equalization, air-spring position, damping performance, tire clearance, and suspension durability.

Axle travel depends on the selected ride height, air springs, shocks or ZMD equipment, tire size, frame clearance, and complete trailer configuration.

Ride Quality and Load Distribution

VANTRAAX uses the low spring rates and large air springs associated with Hendrickson’s integrated trailer suspensions. This helps reduce shock and vibration reaching the trailer frame and cargo.

Moving the tandem forward transfers more weight toward the trailer axles and away from the tractor’s drive axles. Moving the tandem rearward generally transfers weight toward the tractor drives and reduces weight carried by the trailer tandems.

The exact change depends on cargo position, trailer length, kingpin location, fifth-wheel position, and the distance the tandem is moved.

Air suspension helps equalize load between the two trailer axles, but correct ride height and unrestricted air flow are necessary for proper performance.

Suspension Controls and Adjustment Options

VANTRAAX can include several pneumatic and mechanical controls:

  • Height-control valve
  • Suspension dump valve
  • Manual slider pin-pull handle
  • Air-assisted pin-release system where equipped
  • Air-spring inflation controls
  • Pressure-protection valve
  • Brake-system controls
  • ABS components
  • Automatic tire-inflation controls where installed
  • ZMD damping equipment on selected models

To reposition the tandem, the trailer must be secured according to the operating procedure, the locking pins must be fully retracted, and the tractor must move the trailer relative to the stationary slider assembly.

All locking pins must completely reengage before the trailer returns to service.

Alignment and Suspension Geometry

VANTRAAX uses QUIK-ALIGN at the suspension pivot connections. Eccentric and concentric collars allow technicians to adjust individual axle alignment without welding or installing traditional alignment shims.

The tandem axles must be aligned to the trailer kingpin and parallel to each other. The sliding subframe must also sit squarely within the trailer rails.

Important inspection points include:

  • Axle thrust angle
  • Alignment between the tandem axles
  • Slider-box squareness
  • Slider-rail condition
  • Locking-pin engagement
  • Pivot-bushing condition
  • QUIK-ALIGN collar position
  • Pivot-fastener torque
  • Ride height
  • Trailing-beam condition
  • Tire-wear patterns
  • Trailer frame alignment

A misaligned slider box can cause poor tracking even when the individual axles are correctly aligned to each other.

Axle, Brake, and Wheel-End Options

VANTRAAX integrates the trailer axles with the suspension and slider structure. The current listed HKANT uses Hendrickson large-diameter axle technology.

Brake options can include S-cam drum brakes and approved air disc brakes. Brake chambers, slack adjusters, camshafts, brake spiders, rotors, calipers, and ABS equipment vary according to the selected configuration.

Wheel-end options may include conventional-service or extended-service hubs, different spindle arrangements, tire-inflation-system compatibility, and various wheel and tire packages.

The complete trailer capacity is limited by the lowest-rated part of the system. A 40,000-pound VANTRAAX slider does not increase the capacity of lower-rated brakes, tires, wheels, hubs, bearings, or trailer structure.

Common Applications

  • Dry van trailers
  • Refrigerated trailers
  • Specialty van trailers
  • High-cube vans
  • General freight trailers
  • Food-distribution trailers
  • Temperature-controlled trailers
  • Dedicated-route van trailers
  • Parcel and less-than-truckload trailers
  • Trailers requiring adjustable tandem position
  • Weight-sensitive freight operations

Vehicle, Axle, and Frame Compatibility

VANTRAAX is designed for compatible commercial van trailers with slider rails and adequate structural support. Compatibility depends on the trailer manufacturer, rail spacing, slider-box width, suspension ride height, axle spacing, tire size, brake package, frame structure, and intended application.

The listed HKANT 40K is offered with 42- and 48-inch slider-box widths. The correct width must match the trailer’s rail and frame arrangement.

The trailer must provide sufficient clearance for tires, air springs, suspension travel, brakes, and the sliding subframe throughout its complete range of movement.

VANTRAAX should not be installed beneath an unapproved trailer solely because the rail dimensions appear similar. Frame loading, slider stops, locking-pin locations, crossmembers, and structural reinforcement must all be compatible.

Advantages

  • Integrated slider, suspension, axle, and brake system
  • Allows tandem repositioning for weight distribution
  • Designed for dry van and refrigerated trailer applications
  • 40,000-pound system capacity
  • Lightweight construction
  • Air suspension improves ride and cargo protection
  • QUIK-ALIGN simplifies individual axle alignment
  • Large-diameter axle technology in applicable configurations
  • Available air disc brakes
  • Reduced component count
  • Single-source technical and parts support
  • Optional ZMD damping technology
  • Compatible with several wheel-end and tire-management options
  • Established service support across the trailer industry

Limitations or Considerations

  • Primarily designed for compatible van-style trailers
  • System capacity does not establish the ratings of the brakes, wheels, or tires
  • Incorrect ride height can cause unequal axle loading and component damage
  • Slider rails and locking pins require regular inspection
  • All locking pins must fully engage before road operation
  • Corrosion and debris can restrict slider movement
  • Air leaks can lower the trailer or disrupt load equalization
  • Pivot bushings and QUIK-ALIGN fasteners require inspection
  • Improper tandem position can overload the tractor or trailer axles
  • The slider adds more moving parts than a fixed suspension
  • Trailer structure must match the selected slider-box width
  • ZMD and conventional air springs must not be mixed improperly

Driver and Operator Experience

VANTRAAX allows the driver to adjust the tandem position to correct axle weights and meet bridge-law requirements. A properly maintained slider should move smoothly when the locking pins are released and the trailer is positioned correctly.

The air suspension provides a smoother ride than many mechanical trailer suspensions, helping reduce cargo movement and trailer bounce.

Drivers should visually confirm that every locking pin is completely engaged after moving the tandem. They should also watch for low ride height, air leaks, abnormal tire wear, bent pin linkage, damaged rails, or a trailer that tracks to one side.

Maintenance and Ownership Notes

  • Inspect all air springs for cracking, abrasion, contamination, and leakage.
  • Check air lines, fittings, valves, and reservoirs.
  • Verify suspension ride height.
  • Inspect height-control valves and linkages.
  • Check shock absorbers for leakage and damaged mounts.
  • Inspect ZMD air springs and down stops where equipped.
  • Do not mix ZMD and conventional air springs on the same suspension.
  • Inspect pivot bushings and QUIK-ALIGN connections.
  • Check pivot-fastener torque according to Hendrickson procedures.
  • Inspect slider rails for wear, corrosion, cracking, and debris.
  • Check locking pins for wear, bending, and complete engagement.
  • Inspect pin springs, linkage, handles, and air-release components.
  • Lubricate slider components where the manufacturer requires it.
  • Inspect trailing beams, hangers, axles, and crossmembers.
  • Check brakes, ABS components, hubs, bearings, seals, tires, and wheels.

Common Suspension Problems

  • Air leaking from springs, lines, fittings, or valves
  • Trailer sitting below the specified ride height
  • Unequal axle loading
  • Bent or disconnected height-control linkage
  • Worn pivot bushings
  • Loose pivot fasteners
  • QUIK-ALIGN collars moving after adjustment
  • Axle misalignment
  • Trailer dog tracking
  • Irregular tire wear
  • Worn or leaking shock absorbers
  • Damaged ZMD down stops
  • Slider locking pins failing to retract
  • Locking pins failing to engage completely
  • Bent or seized pin-pull linkage
  • Corroded or contaminated slider rails
  • Excessive clearance between the slider box and trailer rails
  • Damaged slider stops
  • Cracked crossmembers or hangers
  • Brake or ABS problems
  • Wheel-bearing or hub-seal failures

Identification Information

Begin identification with the trailer vehicle identification number, manufacturer build sheet, VANTRAAX identification tag, axle serial numbers, suspension model, and brake specifications.

Important identification information includes:

  • Trailer identification number
  • Trailer manufacturer and model
  • Model year
  • Complete VANTRAAX model designation
  • System capacity
  • Axle spacing
  • Slider-box width
  • Suspension ride height
  • Axle type and serial numbers
  • Brake type and size
  • Wheel-end configuration
  • ABS arrangement
  • Air-spring part numbers
  • Shock or ZMD configuration
  • Pivot-bushing type
  • Locking-pin and release mechanism
  • Existing component numbers

A model such as HKANT 40K identifies a particular slider and suspension family, but the complete configuration must be confirmed before ordering parts.

Buying Considerations

  • Confirm the complete VANTRAAX model.
  • Verify the 40,000-pound system rating.
  • Identify the slider-box width.
  • Confirm axle spacing and suspension ride height.
  • Determine whether the system has drum or air disc brakes.
  • Check whether the suspension uses conventional shocks or ZMD technology.
  • Inspect the slider rails for corrosion, distortion, or cracking.
  • Check all locking pins and the release mechanism.
  • Confirm that every pin fully engages its rail hole.
  • Inspect air springs, pivot bushings, and QUIK-ALIGN fasteners.
  • Examine axles, trailing beams, hangers, and crossmembers.
  • Check brakes, ABS, hubs, bearings, seals, tires, and wheels.
  • Look for tire wear indicating axle or slider misalignment.
  • Road-test the trailer for pulling, bouncing, or poor tracking.
  • Verify replacement-part availability using the complete model and serial numbers.

Variants and Configurations

  • VANTRAAX HKANT 40K: Current listed lightweight tandem slider for dry-freight, refrigerated, and specialty van trailers.
  • HKAT Configuration: Earlier or application-specific top-mount VANTRAAX slider design.
  • HKAL Configuration: Application-specific VANTRAAX slider using a low-ride suspension arrangement.
  • HKARL Ramp-Ready Configuration: Specialized slider designed for ramp-compatible trailer applications with a taller slider-box structure.
  • Drum-Brake Configuration: Integrated tandem system using S-cam foundation brakes.
  • Air-Disc-Brake Configuration: Optional integrated system using air disc brakes.
  • Shock-Equipped Configuration: Uses conventional dampers to control suspension movement.
  • ZMD-Equipped Configuration: Uses Hendrickson zero-maintenance damping air springs and down stops on compatible models.
  • 42-Inch Slider Configuration: Designed for trailers using a compatible 42-inch-wide slider box.
  • 48-Inch Slider Configuration: Common van-trailer arrangement using a 48-inch-wide slider box.

Comparison to Similar Equipment

Compared with Hendrickson INTRAAX, VANTRAAX adds a sliding subframe around tandem INTRAAX suspension, axle, and brake assemblies. INTRAAX can be mounted directly to a fixed trailer structure, while VANTRAAX allows the complete tandem group to move.

The Hendrickson ULTRAA-K Slider System is a newer lightweight slider system using Hendrickson’s updated ULTRAA-K suspension and axle technology.

The Hendrickson ULTRAA-K focuses on the integrated lightweight suspension and axle assembly, while the ULTRAA-K Slider System includes the movable subframe.

Compared with SAF-Holland CBX slider systems, VANTRAAX combines Hendrickson slider technology with the INTRAAX suspension, axle, brake, alignment, and optional ZMD systems.

Best Fit For

  • Dry van fleets
  • Refrigerated trailer fleets
  • Specialty van operations
  • Trailers requiring an adjustable tandem position
  • Fleets needing to balance tractor-drive and trailer-tandem weights
  • Operators prioritizing cargo protection
  • Weight-sensitive hauling applications
  • Fleets wanting an integrated suspension, axle, brake, and slider package
  • Applications requiring a 40,000-pound tandem slider
  • Trailers compatible with 42- or 48-inch slider-box widths

Related Vehicle and Trailer Types

Related Truck and Trailer Models

Related Suspension Types

Related Equipment Systems

Related Guides

Regulatory and Compliance Notes

A VANTRAAX-equipped trailer must remain within all applicable gross vehicle, tandem-axle, bridge-formula, tire, wheel, brake, frame, and roadway limits. The 40,000-pound system capacity does not independently establish the trailer’s legal payload.

The tandem position directly affects axle weight and bridge-law compliance. Drivers must confirm axle weights after loading and position the tandem within legal and trailer-manufacturer limits.

All locking pins must be completely engaged before road operation. A slider with partially engaged or damaged pins can move unexpectedly and cause loss of control or trailer damage.

Brakes, ABS components, tires, wheels, and wheel ends must meet applicable commercial trailer safety requirements.

Real World Operating Notes

VANTRAAX combines two systems that require regular attention: the air suspension and the sliding tandem. A well-maintained suspension can still create serious problems if its locking pins or slider rails are neglected.

Drivers should visually check the pins after every tandem adjustment. Pulling the release handle back into position does not prove that every pin has entered a rail hole.

Ride height and alignment also affect operating cost. An incorrectly adjusted or misaligned VANTRAAX can rapidly wear four or eight trailer tires and may create unequal loading across the tandem.

Frequently Asked Questions

What is Hendrickson VANTRAAX?

VANTRAAX is an integrated sliding tandem trailer system combining a slider box, INTRAAX air suspensions, axles, and brakes.

Is VANTRAAX used on trucks or trailers?

It is designed for commercial trailers, especially dry vans, refrigerated trailers, and specialty vans.

What is the capacity of VANTRAAX HKANT 40K?

The listed system capacity is 40,000 pounds.

What is the axle spacing?

The current listed HKANT 40K uses 49-inch tandem axle spacing.

What ride heights are available?

The listed HKANT 40K is available with 16- or 17-inch suspension ride heights.

Why does a trailer need a sliding tandem?

Moving the tandem changes the weight distribution between the tractor’s drive axles and the trailer axles. It also affects bridge-law measurements and maneuverability.

What is the difference between VANTRAAX and INTRAAX?

INTRAAX is the integrated suspension, axle, and brake system. VANTRAAX mounts tandem INTRAAX assemblies within a sliding subframe.

Can VANTRAAX use air disc brakes?

Yes. Air disc brakes are available on approved configurations.

What is QUIK-ALIGN?

QUIK-ALIGN is Hendrickson’s axle-alignment system using eccentric and concentric collars at the suspension pivot.

Can VANTRAAX use ZMD technology?

Selected VANTRAAX models can use ZMD air springs and down stops instead of conventional shock absorbers.

What causes a VANTRAAX slider to stick?

Common causes include rail corrosion, accumulated debris, bent locking pins, damaged linkage, trailer misalignment, or load binding the slider.

How can a driver confirm the tandem is locked?

The driver should visually inspect both sides of the trailer and confirm that all locking pins extend completely through the appropriate rail holes.

Does moving the tandem change the trailer’s total weight?

No. It changes how the existing weight is distributed between the tractor and trailer axle groups.

Availability and Where to Find

Hendrickson VANTRAAX is available through participating dry van, refrigerated trailer, and specialty trailer manufacturers. It can also be found on a large number of used commercial van trailers.

Replacement air springs, shocks, ZMD components, pivot bushings, QUIK-ALIGN hardware, locking pins, slider parts, brakes, hubs, bearings, seals, and axle assemblies are available through Hendrickson distributors, trailer dealers, repair facilities, and heavy-duty parts suppliers.

Current specifications can be checked through Hendrickson’s official VANTRAAX HKANT 40K product page and L707 trailer suspension application guide.

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