AirLiner, TufTrac, Haulmaax, and Primaax: Freightliner's Severe-Duty Suspension Options Compared

Spec out a Freightliner severe-duty truck like the 114SD Plus or 108SD Plus and you will hit a suspension decision with more real options than most contractors realize exist. Freightliner offers its own proprietary AirLiner and TufTrac systems alongside Hendrickson-built Haulmaax and Primaax units as factory-available options, and the four systems are genuinely different pieces of engineering built for different jobs, not four marketing names slapped on the same hardware. Getting this spec wrong is not a fatal mistake, most of these systems can handle most vocational work adequately, but getting it right means less driver fatigue, less wear on the truck, and a better match to the ground your trucks actually run on every day.

Why Freightliner Offers Four Systems Instead of One

It would be simpler for Freightliner to pick a single suspension and put it under every severe-duty truck, so the fact that the company offers four genuinely different systems, two of its own design and two licensed from a specialist supplier, says something about how differently a dump truck hauling debris over broken pavement rides compared to a mixer running mostly paved routes between a batch plant and a pour site, and how differently a crane carrier or heavy-haul chassis loads its rear suspension compared to either one. A one-size-fits-all suspension spec would necessarily be a compromise for most of those applications. Offering four real choices puts the compromise decision in the buyer's hands instead of the factory's.

AirLiner: Freightliner's Own Air-Ride System

AirLiner is Freightliner's proprietary air suspension, offered in a full selection of single and tandem drive configurations tuned for a wide range of vocational applications, with a heavy-duty version rated up to 46,000 pounds for trucks carrying larger payloads. As an air system, AirLiner isolates the frame and cab from road shock far more effectively than a mechanical leaf-spring or walking-beam design, which is the core tradeoff every air suspension makes: smoother ride and less cumulative wear on pavement-heavy routes, in exchange for somewhat less mechanical robustness on the roughest off-road ground compared to a walking-beam system built for exactly that kind of abuse.

What Fleets Ask For and Why It's Not Always the Obvious Answer

It is common for a first-time buyer to assume air suspension is simply the better, more modern choice across the board, the way it has become the default on most highway tractors. That assumption holds up less cleanly on the vocational side, where a dump truck's job frequently involves exactly the kind of off-pavement abuse air suspensions are more vulnerable to. A dealer who understands your actual routes, not just your GVWR and axle count, is worth pushing for a real recommendation from rather than defaulting to whatever suspension happens to be the standard order on the truck you are configuring.

TufTrac: A Mechanical System With an Air-Ride Feel

TufTrac takes a different approach, combining parabolic leaf springs with elastomeric load cushions rather than going fully pneumatic. A center elastomer load cushion acts as a pivot point that allows the suspension to articulate more like an air-ride system while retaining the mechanical simplicity and durability that leaf-spring designs are known for. The Comfort Ride version of the current TufTrac Gen2 suspension is available in 40,000-pound and 46,000-pound tandem axle capacities, aimed specifically at vocational buyers who want a softer, more air-ride-like feel without giving up the lower maintenance complexity of a mechanical system. It is, in a real sense, Freightliner's answer for a contractor who wants most of what an air suspension delivers without fully committing to one.

Haulmaax and Primaax: Hendrickson's Vocational and Heavy-Haul Options

Haulmaax and Primaax EX are not Freightliner's own designs, they are Hendrickson-built suspensions offered as factory options across many vocational chassis manufacturers, Freightliner included. Primaax EX is Hendrickson's severe-duty vocational and heavy-haul rear air suspension, engineered for the most demanding applications and available in configurations up to 52,000-pound capacity with air disc brake clearance built in for fleets speccing that brake architecture. Haulmaax fills a similar severe-duty niche with a mechanical, high-articulation design more comparable to a walking beam than to AirLiner's pneumatic approach, aimed at the roughest ground a dump truck, crane carrier, or heavy-haul chassis is likely to cross. Choosing Hendrickson hardware over Freightliner's own AirLiner or TufTrac is not a downgrade, it simply reflects that Hendrickson has spent decades specializing in exactly this category of severe-duty suspension and many fleets spec it specifically for that pedigree and for parts commonality across a mixed-brand fleet.

A Word on Brake Clearance and Component Compatibility

Suspension choice also interacts with brake system choice in ways worth flagging before you finalize a spec. Primaax EX, for instance, is specifically engineered with clearance for air disc brakes built into its newer configurations, which matters if your fleet is standardizing on air disc brakes the way our air disc vs. S-cam drum brake comparison discusses. Not every suspension and brake combination is a drop-in fit without engineering review, so it is worth confirming compatibility between your chosen suspension and brake architecture with your Freightliner dealer at the same time you are speccing the rest of the chassis, rather than treating the two decisions as fully independent.

What Each System Actually Costs to Own Over Time

AirLiner and Primaax EX, as air systems, share the maintenance profile common to pneumatic suspensions generally: air dryers, height-control valves, and airbags that need periodic inspection, with a higher per-incident repair cost when something fails but generally less cumulative wear transmitted into the frame, cab mounts, and whatever cargo is riding behind the cab, concrete drum included. TufTrac and Haulmaax, leaning more mechanical, trade some of that ride isolation for the lower complexity and wider service familiarity that comes with leaf springs and elastomeric cushions rather than electronically managed airbags. A fleet already running Hendrickson suspensions on other brands in a mixed fleet has a real argument for specifying Haulmaax or Primaax EX on a new Freightliner purchase purely for parts and service commonality, even if AirLiner or TufTrac might be a marginally better engineering fit for the specific application. That kind of fleet-wide consistency is a legitimate factor, not a compromise, when it cuts down on the number of different suspension parts a shop has to stock.

Matching the Suspension to the Job, Not Just the Chassis

A demolition contractor hauling debris over broken pavement and job-site rubble, or an aggregate hauler running unimproved quarry roads all day, is a stronger candidate for Haulmaax or a mechanical TufTrac spec, prioritizing durability and articulation over outright ride comfort. A ready-mix hauler running a mixer built on a 114SD Plus between a batch plant and mostly paved job sites, by contrast, is a better fit for AirLiner or Primaax EX, where the smoother ride reduces both driver fatigue over a long delivery day and the cumulative wear that comes from constant road shock transmitted into a drum full of curing concrete. Getting this decision right at the time of order is far cheaper than living with the wrong suspension spec for the life of the truck, since retrofitting a different system after the fact is a major, and rarely cost-effective, undertaking.

Ride Height and Ground Clearance Deserve a Look Too

Suspension choice on a severe-duty Freightliner is not purely about ride quality and durability, it also affects ride height and ground clearance, which matters more than it might seem for both dump and mixer applications. A mixer running curb-height approaches at residential jobs benefits from a suspension configuration that keeps ground clearance reasonable without sacrificing frame height needed for the drum and its drive components, while a dump truck crossing rough or graded terrain benefits from maximizing that clearance to avoid dragging the frame or a rear-mounted PTO housing over uneven ground. Hendrickson's Primaax EX line, for instance, offers configurations built around specific ride-height requirements for exactly this reason, and it is worth asking your dealer directly how each suspension option affects your specific body's ground clearance before finalizing a spec, rather than assuming all four systems behave identically once a body is mounted.

How This Fits Into a Real Buying Decision

None of these four systems is the objectively correct choice, and a Freightliner dealer will spec the truck around the application you describe, but knowing the real tradeoffs, air versus mechanical, Freightliner-proprietary versus Hendrickson, going in means you are directing that conversation instead of just accepting whatever the dealer defaults to. If you are still deciding between the 108SD Plus and 114SD Plus chassis these suspensions mount to, our sizing breakdown of the 108SD Plus vs. 114SD Plus is the right place to start. Our wide-base single vs. dual tire comparison covers a related running-gear decision worth making at the same time, and our GVWR and CDL classification guide explains how the weight rating tied to your suspension choice affects who can legally drive the finished truck.

A Quick Reference for the Conversation With Your Dealer

Boiled down, AirLiner is Freightliner's own general-purpose air suspension for a broad range of vocational work up to 46,000 pounds. TufTrac is the mechanical-with-an-air-feel option for buyers wanting a softer ride without full air-system complexity, in 40,000- and 46,000-pound tandem capacities. Haulmaax is Hendrickson's severe-duty, high-articulation mechanical system for the roughest ground a truck is likely to cross. Primaax EX is Hendrickson's severe-duty air suspension for heavy-haul and vocational work up to 52,000 pounds, with air disc brake clearance built in. Walking into a spec conversation already knowing which category your work actually falls into turns that meeting into a confirmation rather than a guessing game.

Owning the Right Spec Instead of Renting Whatever's Available

A rental fleet's suspension spec was chosen long before you ever needed the truck, usually optimized for the broadest possible range of customers rather than your specific ground conditions. Financing your own 114SD Plus or 108SD Plus means you choose AirLiner, TufTrac, Haulmaax, or Primaax EX based on the actual routes and jobsites your trucks run every day, and every payment builds equity in a truck configured for your work instead of a rental invoice for someone else's generic spec.

Ready to Put This to Work on Your Fleet?

Whether you're speccing your next dump truck, adding a mixer to a growing fleet, or just keeping tabs on what Mack and Freightliner are building next, BFC Equipment Loans works with contractors who'd rather own their equipment than keep feeding a rental company every month with nothing to show for it afterward. Ready to move on a truck? Start your equipment financing application and we'll walk you through it. Buying or selling used iron in the meantime? Check our equipment for sale marketplace. And if you want more breakdowns like this one before your next purchase, subscribe to the BFC blog for regular coverage of the equipment that actually moves dirt and pours concrete.