Professional 5 Stage Telescopic Dump Truck Hydraulic Cylinder

Professional 5 Stage
Dump Truck Cylinder
When One Cylinder Isn't Enough

Most dump trucks use a single telescopic hydraulic cylinder — one cylinder, centred between the chassis rails, tipping the dump body. But some applications require two cylinders working in parallel: one on each side. This dual-cylinder configuration is used when the payload exceeds a single cylinder's capacity, when the dump body is too wide for stable single-point tipping, or when the frame geometry cannot accommodate one large-bore cylinder but can fit two smaller-bore cylinders.

Payload Exceeds Single-Cylinder Capacity

Large dump trucks carrying 30–50+ tonnes may require more lifting force than a single 6-inch bore cylinder can produce at the available system pressure. Rather than exceeding the bore range (which would require non-standard manufacturing), two cylinders at 4–5 inch bore each produce double the force — within the standard bore range. Each cylinder operates within its rated capacity, and the combined force tips the heavy body reliably. This approach also provides redundancy: if one cylinder develops a seal leak, the other cylinder can still hold the body in a partially tipped position until the truck reaches the workshop.

Extra-Wide Dump Bodies

Standard dump bodies are approximately 2.3–2.5 metres wide — a single centre-mounted cylinder tips the body evenly. But some specialised dump bodies (agricultural grain trucks, wide-bed construction haulers) are 2.8–3.5 metres wide. A single centre-mounted cylinder on an extra-wide body creates an unstable tipping geometry: the body tends to twist or flex during tipping because the lifting force is applied at a single point far from the body edges. Two cylinders — one on each side — apply force at two points spanning the body width, eliminating the twist and providing stable, level tipping across the full body width.

Frame Cannot Accommodate One Large-Bore Cylinder

Some chassis frame geometries (cross-members, fuel tanks, exhaust systems, air tanks) block the centre position where a single large-bore cylinder would mount. Two smaller-bore cylinders can be positioned outboard — one on each side of the obstruction — fitting into frame spaces that a single large-bore cylinder cannot. This is common on truck chassis that were not originally designed for dump body conversion: the existing frame components cannot be relocated, so the cylinders must fit around them.

Matched manufacturing tolerances

The primary synchronisation method is manufacturing precision. If both cylinders have identical bore diameters (within tight tolerance), the same hydraulic flow produces the same extension speed in both. Korea Ever-Power manufactures matched pairs on the same production run with dimensional matching verified — both cylinders' bore diameters are measured and paired to be within ±0.05 mm of each other. This inherent dimensional match provides passive synchronisation without additional hydraulic circuitry.

Flow divider valve (active synchronisation)

For applications requiring precise synchronisation (tilting platforms, precision discharge), a flow divider valve can be installed between the pump and the two cylinders. The flow divider splits the pump output into two equal flows — one to each cylinder — regardless of load differences between the two sides. Flow dividers add cost and a small pressure drop, but provide the tightest synchronisation possible. For most dump truck tipping applications, matched manufacturing tolerances provide adequate synchronisation without a flow divider.

Can I replace just one cylinder in a matched pair, or must I replace both?

Replacing just one is acceptable if the replacement is manufactured to the same specification and bore tolerance as the original pair. When ordering a single replacement for a dual-cylinder hoist, provide the serial number of the remaining cylinder — the factory can reference the original production records to ensure the replacement matches. Ideally, order the replacement from the same manufacturer (Korea Ever-Power) to ensure dimensional consistency. Mixing manufacturers in a matched pair risks synchronisation problems.

Do I need a flow divider for a dump truck dual-cylinder hoist?

For most dump truck tipping applications, no. Manufacturing-matched bore tolerances provide adequate synchronisation for dump body tipping — the body rises level within practical limits. Flow dividers are recommended for precision applications where exact synchronisation is critical (e.g. vehicle transport platforms, tilt-deck trailers where the deck must remain precisely level). If your dump body tilts slightly to one side during tipping, a flow divider may help — but first check whether the cylinders are genuinely matched or were sourced from different batches.

Is the tipping speed halved with dual cylinders?

It depends on the pump flow. If the same pump feeds both cylinders through a flow divider, the flow to each cylinder is halved — and the tipping speed is approximately halved compared to a single cylinder at the same bore. However, each cylinder in a dual configuration typically has a smaller bore than a single-cylinder equivalent, which means each stage's piston area is smaller — partially compensating for the reduced flow. To maintain the same tipping speed as a single-cylinder system, increase the pump displacement or flow rate proportionally.

Does a dual-cylinder hoist cost twice as much as single?

The cylinder cost is approximately double (two cylinders instead of one), but each cylinder may be a smaller bore than the single-cylinder equivalent — partially reducing the per-unit cost. The total system cost is more than double because you also need a flow divider (if used), twice the hose lengths, additional fittings, and dual mounting brackets. Typical total dual-cylinder hoist cost is approximately 2.2–2.8× a single-cylinder hoist of equivalent total force. The same matched-pair approach applies to forklift applications (dual lift cylinders) and aerial work vehicle configurations (dual boom cylinders).

Our 40-tonne off-highway dump trucks exceed the capacity of a single 6-inch bore cylinder at our system pressure. We use matched pairs of 5-stage 5-inch bore cylinders — one on each side. The Ever-Power matched pairs have bore tolerance within 0.03 mm between the two cylinders in each set. Without a flow divider, the tipping synchronisation is within 10 mm across the full stroke — acceptable for bulk material tipping. 20 matched pairs (40 cylinders) delivered over 12 months, all dimensionally matched. The dual-cylinder redundancy also gives our operators confidence — if one cylinder develops a minor leak, the other holds the body while they lower it safely.

Our grain trucks have 3.2-metre wide dump bodies — a single centre-mounted cylinder caused the body to twist during tipping, cracking the hinge welds. Switched to dual Ever-Power 5-stage cylinders, one on each side of the body. The two-point lift eliminated the twist completely — the body rises level and the hinge loading is evenly distributed. We use a simple tee fitting (no flow divider) and the matched manufacturing tolerances keep the synchronisation within 15 mm across the full stroke. 6 matched pairs, all performing well after 8 months of grain harvest tipping.

We convert cargo truck chassis to dump body configuration. Some chassis have a large fuel tank and exhaust silencer in the centre — blocking the single-cylinder mounting position. Two smaller 5-stage cylinders fit outboard on each side of the obstructions. Four stars because the dual-cylinder setup requires twice the hose plumbing and a flow divider to ensure level tipping — the total conversion cost was about 2.5× a single-cylinder hoist. But there was simply no space for a single large-bore cylinder on these chassis. The Ever-Power matched pairs solved the space problem while providing adequate force for our 15-tonne dump bodies.