In short: Mechanical leaf spring suspension is standard on every trailer we build and air suspension can be specified on request. The choice is decided less by comfort than by three practical things: the surface the trailer works on, what your local parts counter actually stocks, and whether your loads need the ride height to stay constant. A third type, bogie or rigid suspension, is not in our standard range.
Suspension is the system that carries the load from the trailer frame down to the axles and absorbs the road on the way. On a laden semi trailer working a haul route, it is also the part most likely to be serviced at the roadside, which is why the practical questions matter more than the brochure ones.
What a suspension actually does
- Carries the vertical load from the main beam into the axle group.
- Absorbs road input so the frame, the cargo and the tyres see less shock.
- Locates the axles so the group tracks straight and the tyres wear evenly.
- Sets ride height, which decides deck height and how the trailer sits when loaded.
Every type below does all four. They differ in how, and in what it costs to keep them doing it.
Mechanical leaf spring – our standard
Mechanical leaf spring is standard across our range, including on the skeleton container chassis and the flatbed and side wall builds, where the published specification is 10 pcs x 90 x 13 mm leaf springs.
Why it stays the default on an export trailer:
- Repairable anywhere. A broken leaf is a stock item in most markets and can be replaced without specialist equipment or a diagnostic tool.
- Fewer failure points. No air bags, no levelling valves, no airlines running to the axle group.
- Predictable on poor surfaces. On gravel, unpaved haul roads and rough tip sites, the simpler system is the more forgiving one.
- Lower first cost, which matters most on a first order.
The trade-off is a firmer ride and a ride height that changes with load. On a trailer carrying containers or bulk, that is usually an acceptable trade.
Air suspension – optional on request
Air suspension can be specified on request across the range. It is worth pricing when one of these is true:
- Ride height has to stay constant. Some loading bays, ramps and container handling setups need the deck at one height whether the trailer is empty or laden.
- The cargo is shock-sensitive. Air isolates the load from road input far better than steel springs.
- You run the same fleet standard. If your existing units are all on air, a steel-spring newcomer complicates your parts inventory and driver expectations.
- Tyre and road-damage cost matters more than parts simplicity. Air reduces the peak loads the tyres and frame see.
The trade-off is real: more components to fail, airlines and valves to protect, and a repair that needs parts your local counter may not stock. On the roads many of our customers run, that is the deciding factor against it.
Bogie or rigid suspension
Bogie, or rigid, suspension is a third type you will see in the market – the axles are held rigidly rather than on springs, which suits some slow-speed heavy-haul and specialised work.
It is not part of our standard range. We are telling you that plainly rather than quoting it as an option. If your operation genuinely needs it, say so in your enquiry and we will tell you whether it is something we can source, rather than selling you a trailer that does not suit the job.
How to choose
- What surface does the trailer work on? Sealed road and port aprons point one way; gravel haul roads and rough tip sites point the other.
- What does your local parts counter stock? This is the question buyers skip and regret. A system you cannot buy parts for locally is the wrong system regardless of how good it is.
- Does ride height matter? If it does, that is an air suspension conversation.
- What is the load and how is it applied? Impact loading from a face shovel or excavator is a different duty from road haul, and it changes what the suspension sees.
- What are your other units on? Fleet standardisation is a real cost saving and rarely priced in.
The spec sheet line to check
Whatever you choose, the quote should say which type, and for steel springs it should also give the spring pack. “Mechanical suspension” alone does not tell you whether the pack suits the load, and it is the line most often left vague. Ours is published per model – ask any supplier for the same.
FAQ
Is air suspension better than leaf spring?
Not in the abstract. Air gives a softer ride and constant ride height; steel springs are simpler and easier to repair locally. On rough roads and in markets with thin parts supply, steel is usually the better engineering answer.
Can I order air suspension on any model?
It is available on request across our range. Tell us at the quoting stage so it is priced in rather than added later.
Do you build bogie suspension?
It is not in our standard range. Ask us directly if your operation needs it and we will answer plainly rather than assume.
Does suspension choice affect the warranty?
Every trailer we ship carries twelve months on the frame and running gear. What changes with the choice is serviceability – read how a claim or parts request is handled before deciding.
Key facts
- Mechanical leaf spring suspension is standard on every trailer we build; published spring pack is 10 pcs x 90 x 13 mm on flatbed and skeleton builds.
- Air suspension is available on request across the range.
- Bogie or rigid suspension is not in our standard range – ask and we will answer plainly.
- Steel springs are simpler to repair locally; air gives constant ride height and better load isolation.
- The choice should follow road surface, local parts availability, ride-height need and fleet standardisation.
- Twelve months warranty on the frame and running gear.
Related: axle brand versus rating, Q345 versus T700 main beam steel, and how axle count changes the trailer.
