Volume is the wrong number to start with
Nine out of ten tipper trailer enquiries we receive open with a cubic metre figure — 30 CBM, 42 CBM, 50 CBM. Then the buyer mentions the cargo: wet sand, or coal, or clay.
Those three materials behave nothing alike. A 42 CBM body loaded with wet sand is roughly 65 tonnes. The same body loaded with coal is around 35 tonnes. Same trailer, twice the load, and one of those loads will destroy the body long before the warranty expires.
So before choosing a volume, work out the tonnage. Volume * bulk density = the number that decides your axle count, your floor thickness and your hydraulic cylinder.
Bulk density cheat sheet
| Material | Bulk density (t/m³) | What it means for the body |
|---|---|---|
| Dry sand | 1.4–1.6 | Heavy per m³ — floor wear and axle load dominate |
| Wet sand / gravel | 1.7–1.9 | Cap volume at 30–35 CBM on 3 axles |
| Crushed stone | 1.5–1.7 | Impact load on floor when dumped |
| Coal | 0.8–0.9 | Volume-limited, not weight-limited — 50 CBM works |
| Wheat / maize | 0.7–0.8 | Needs sealed tailgate, smooth interior |
| Wet clay / mud | 1.8–2.0 | Sticky — discharge angle and liner matter more than steel |
If you haul two or three of these, size for the heaviest and accept that coal runs will be part-loaded. If you haul only coal or grain, buy the big body and save the weight.
Body volume in practice
Common bodies we build: 20, 24, 30, 35, 42 and 50 CBM, with overall length typically 7,500–10,500mm, side wall 8mm and floor 10mm on the heavier units.
A 3-axle chassis usually tops out around 40 tonnes of cargo in most export markets. Push a 50 CBM body onto a 3-axle chassis and you have built a trailer that is only legal when it is half empty. That is not a bargain — it is a trailer that will be overloaded every day and crack at the side beam within two seasons.
Quick rule of thumb
- 3 axles, sand and gravel: 30–35 CBM
- 3 axles, coal and grain: 40–50 CBM
- 4 axles or a drawbar combination, heavy aggregate: 40 CBM plus
Lifting type: front, underbody or side
The hydraulic arrangement decides how the trailer behaves when the body goes up, and how much maintenance you inherit.
Front lifting (front-end telescopic)
One or two multi-stage cylinders at the front bulkhead push the body up and back. Fast raise, high dump angle, good for sticky loads because the load slides down a steep incline. Most of our tipper production is front lifting for exactly this reason.
- Pros: fast cycle, clean discharge, fewer hoses exposed under the chassis
- Cons: high point load at the front bulkhead — the bulkhead and front cross member must be reinforced, not just thick
- Watch: cylinder stage count and the pump flow rate. A 5-stage cylinder on a small pump raises slowly and heats the oil
Underbody (U-shaped) lifting
A single long cylinder under the floor, usually with a U-shaped or half-pipe body. Lower centre of gravity and a lower loading height, which suits excavator loading and low-clearance sites.
- Pros: stable, low loading height, simple geometry
- Cons: cylinder and hoses sit under the load and take stone impacts; discharge angle is shallower so wet clay can hang up
Side lifting
Rare but useful for side-discharge into trenches or along road edges. Narrow applications, more custom fabrication. Ask for a drawing before you commit.
Steel specification that survives the job
| Part | Standard build | Heavy-duty option |
|---|---|---|
| Side wall | 8mm | 10mm, or NM400 wear plate in the impact zone |
| Floor | 10mm | 12mm, or 8mm + 4mm NM400 liner |
| Side beam | 140# square tube | 160# square tube with internal gussets |
| Front bulkhead | 6mm with vertical ribs | 8mm with boxed ribs at cylinder mount |
| Main chassis beam | 500mm, 10/6/12mm | Same section, full-length web stiffeners |
| Paint | Shot blast Sa2.5 + polyurethane | Epoxy primer + 2 topcoats |
Thickness alone does not make a body last. The failures we see in the field come from three places: the junction between floor and side wall (water sits there), the cylinder mount on the front bulkhead, and the hinge pin bosses at the rear. Ask your supplier for photos of those three areas on a finished unit. If they hesitate, keep shopping.
Chassis and running gear
- Axles: 13t FUWA or BPW pattern *3, 16t for mining duty
- Suspension: mechanical leaf spring 10/10/10 with 4 equalisers; reinforced spring seats on tipper duty
- Tyres: 12R22.5 or 12.00R20, 13 pieces including spare, 8.5 rims
- Brakes: 6 brake chambers, 24V system, ABS standard on export units; WABCO valve block on request
- Kingpin: JOST 90# bolt-in
- Landing legs: JOST 28t two-speed. A tipper body dropped on its legs while loaded needs the heavier rating
- Hydraulics: Chinese or imported cylinder, PTO-driven gear pump, oil tank sized for full stroke plus 15% reserve
Discharge behaviour: the part nobody tests
Dump angle on a front-lift tipper runs around 45–50 degrees. Wet clay and mud still hang up. Three practical fixes, in order of cost:
- Polyethylene liner on floor and lower side walls — cheap, replaceable, works on damp clay and grain
- NM400 wear plate floor — solves abrasion, not sticking
- Vibrator pad or air cannon point on the side wall — solves the last 10% of sticky load, needs air supply
Also specify the tailgate seal. A rubber lip seal plus a top-hinged gate keeps grain in on the highway. A plain steel-on-steel gate leaks a trail of product for the whole trip, and buyers notice.
Safety points to write into the contract
- Stability on side slopes. A raised tipper is a lever. Specify a tilt warning or at minimum a decal set and operator note about dumping on level ground only.
- Hose routing. High-pressure lines should run in protected channels, not cable-tied to the chassis where stones hit them.
- PTO interlock. The pump must not engage unless the parking brake is set.
- Rear hinge pins and locking pins, grease points. Ask for the lubrication chart — 12 points, weekly.
Buying, shipping and after-sales
Tipper trailers ship as flat rack or break bulk; a fully assembled 42 CBM body does not fit a 40HQ. Confirm the loading plan, because a body built 20mm over the flat rack width becomes a port problem, not a factory problem.
Typical terms from our plant: 30% T/T deposit, balance against the bill of lading copy, or L/C at sight. Production is 25–35 days depending on body size and hydraulic brand. Loading from Qingdao or Lianyungang, roughly 30–45 days sailing to West Africa, 20–30 days to Southeast Asia.
Spare parts worth shipping with the trailer: cylinder seal kit, PTO shaft, one hydraulic hose set, brake chambers, and a set of light lenses. These are the items that stop a tipper for a week in a market where the local dealer stocks nothing.
FAQ
Can I get a 50 CBM tipper on 3 axles?
Yes, and it is common for coal and grain. Just accept that with sand or gravel you will be volume-limited before you are weight-limited. If your cargo mix is heavy, buy 35 CBM and stay legal.
Front lifting or underbody — which lasts longer?
Both last if built properly. Front lifting loads the bulkhead harder; underbody loads the cylinder and hoses with stone impact. For aggregate and demolition work, front lifting with a reinforced bulkhead is the safer default.
What hydraulic brand do you use?
Chinese cylinders from established suppliers as standard, with imported options on request. What matters more is the stage count, the pump flow and whether the oil tank has capacity for a full raise. Ask for those three numbers.
How thick should the floor be?
10mm for sand, gravel and general aggregate. Step up to 12mm, or add a wear liner, for demolition rubble and blasted rock. Below 8mm on a 40-tonne load, expect floor plate replacement inside three years.
Do you supply semi tipper trailers for mining duty?
Yes — 4-axle and 40–60 tonne class units with 16t axles, reinforced side beams and NM400 liners. Send the material type and daily tonnage and we will spec the body around it.
How we would spec it
Sand and gravel operation, 200km highway runs: 3 axles, 32 CBM, front lifting, 8mm sides, 10mm floor, mechanical suspension, polyethylene liner. Coal or grain: 3 axles, 45–50 CBM, front lifting, sealed tailgate, 8mm sides, 10mm floor, no liner. Demolition and rock: 4 axles, 35 CBM, 10mm sides, 12mm floor with NM400 liner, 16t axles.
Tell us the material, the density and the daily tonnage. We will send a drawing with the dump angle marked on it, plus the cylinder and pump specification, so you can check the numbers yourself before you pay a deposit.
