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Dump trucks: payload limits, body-volume labels and complete haul cycles

Dump trucks for off-highway work should be matched to the actual material, loading method, haul route and discharge arrangement. Rated payload and body volume impose different checks; neither articulated nor rigid chassis labels guarantee safe travel on weak ground or slopes. Cat’s cited 745 configuration lists a 41 t payload and 26 m³ heaped body under SAE 2:1, while the same page separately lists a 27.3 m³ tailgate-heaped option. Dividing 41 by 26 gives about 1.58 t/m³, a relationship between two specifications rather than permission to heap every material. With expressly assumed 40 t allowable payload and 9 t per complete bucket pass, four passes carry 36 t and a fifth reaches 45 t, exceeding that assumed allowance. Use measured load information and the actual body, distribution, braking and retarding limits, then include descent, turning and supported discharge conditions in the route assessment.

Dump trucks need separate payload, body-volume and loading checks

Assumed 40 t payload allowance and 9 t per complete bucket pass
Complete passesCalculated materialComparison with assumed allowance
436 t4 t below
545 t5 t above
What should lead an off-highway dump-truck comparison?

Define the material and its loading characteristics, loading equipment, haul distance and profile, surface and discharge method. Identify the truck rating and fitted body. Articulated and rigid machines have different arrangements, but the planned route and actual operating limits determine whether a particular package can perform the work.

Which Cat 745 payload and body figures belong together?

The cited Cat 745 product reference lists 41 t rated payload and 26 m³ heaped body capacity at SAE 2:1. The tailgate-heaped option is 27.3 m³.

Keep body version and volume together. Another regional specification may describe a different configuration.

What does the 41 t divided by 26 m³ calculation establish?

The quotient rounds to about 1.58 t/m³. It compares the stated payload with the stated heaped volume and does not measure the hauled material’s actual density. Loading still requires the truck’s actual permitted mass, body configuration, distribution and operating conditions; an apparent volume fit cannot establish that the payload or another limit is respected.

How are full bucket passes checked against an assumed payload?

With expressly assumed 40 t allowable payload and 9 t carried per complete pass, four passes total 36 t and five total 45 t. A fifth full pass is 5 t over. Actual bucket variation, material, retained load, body space and distribution need assessment; this calculation neither rates the Cat 745 nor approves a particular partial final pass.

Match the actual loader and record the complete cycle

Must every truck-loading match use three to six passes?

Deere’s 904 P-Tier page describes a two-pass solution for standard over-the-road trucks. That application is for over-the-road trucks. It shows why a universal three-to-six-pass requirement is inappropriate: identify the actual loader, truck, material and allowed loading arrangement before deciding how many passes form a useful match.

Does bucket volume directly establish material mass per pass?

Use the applicable fill condition and representative material density or measured weights, retaining the load variation. Measure carried volume or mass for the material.

A copied density can misstate the load. Check permitted payload and available body space together.

Catalog bucket volume alone cannot select the pass count.

What changes the usable payload of an offered truck?

Resolve the actual rated configuration, body, liners, attachments, retained material and applicable loading instructions. Retain equipment mass and load distribution. A headline payload from another body package cannot establish the allowance of the offered machine, and a body that can physically contain more material is not a capacity upgrade.

How should loader and truck timing be compared?

Include measured loading, positioning, loaded travel, discharge, return and waiting times on the actual route. Record measured cycles separately from availability assumptions. More trucks do not automatically improve loader output if queues or discharge restrictions dominate, while a theoretical pass calculation alone cannot establish the fleet needed for the planned production rate.

Assess descent, terrain and discharge for the configured truck

Which information governs descent and stopping?

Use the actual gross mass, route and manufacturer grade, speed, braking and retarding information. Retarding systems manage energy through particular arrangements; their presence does not eliminate every brake or cooling limit.

Assess surface, visibility, turning and stopping along the route. Maximum speed and chassis labels cannot settle those conditions.

Does articulation guarantee all wheels stay loaded on rough ground?

Articulation and oscillation can help accommodate terrain, but actual geometry, load and surface still determine support. Neither feature guarantees support on every slope. Rigid trucks also have different axle and drive arrangements, so establish the actual machine instead of assigning all trucks one driven-axle layout or one ground capability.

What must be checked before raising a dump body?

Follow the actual discharge procedure and assess ground support, level conditions, clearance and the permitted work area. Check the actual discharge mechanism’s procedure. Keep people clear of hazardous movement and use the specified body support before any work beneath raised equipment; hydraulic control position or a stationary engine alone cannot establish a safe service setup.

What should be retained with a used-truck quotation?

Identify the truck, body and loading configuration, actual condition findings, service history and required repairs to structure, running gear, braking, retarding and discharge systems. Compare offers on the same loaded haul duty. A nominal payload or one successful empty run cannot demonstrate the complete loaded route performance or settle the ownership decision.

Compare wheel loaders, excavators and haul-fleet calculations. Browse machine classes.

Choose the truck around the whole loaded route

Record loading and discharge points, haul distance, grade changes, bends, road width, visibility and support. Distinguish loaded and return travel and include where trucks can wait or pass. An articulated chassis can accommodate terrain differently from a rigid one without certifying that every unprepared route is suitable.

Identify the actual axle, steering, drive and suspension arrangements. Articulation or oscillation does not guarantee that every wheel remains supported or that a loaded truck can cross any slope. A rigid truck is not defined by one universal driven-axle count.

Use the named machine's conditions and route assessment rather than assigning either class a fixed operating cost per tonne.

Keep body space, material mass and distribution separate

Retain the stated struck or heaped rating basis and any tailgate, liner or body option. A geometric heap describes volume under its specified method. It does not measure actual payload, account for retained sticky material or approve a load piled differently from the supported arrangement.

Use representative material density or measured load information with the allowed payload and distribution. The loader's bucket rating is not automatically the volume carried on every pass. Track variation, residual material and the last partial load under the actual loading method instead of treating a rounded full-pass calculation as permission to overload.

Match the loading machine to truck positioning and receiving height as well as mass per pass. A larger loader may shorten one part of the cycle while changing access, bucket clearance or the number of trucks needed. The correct comparison includes loading, travel, discharge and waiting; no fixed pass-count band establishes the best fleet for every job.

Read the descent and discharge requirements before production

Obtain the braking, retarding, grade and speed information for the actual gross mass and route conditions. Retarders manage energy through their particular system and have their own limits. Their presence does not remove service-brake, cooling, tire or traction requirements or establish a safe speed from a maximum catalog travel figure.

Assess the dump point for support, level conditions, overhead hazards and separation from people and other equipment. Raising a body changes the machine's geometry and the material movement. A tailgate, tipping body and ejector arrangement each needs its own approved procedure and material suitability; none guarantees that a hung load can be released by an improvised maneuver.

Use the specified body support and isolation before inspection or service beneath raised equipment. Record structural, hinge, body-floor, discharge, brake and retarder findings alongside the truck's identity. Inspect an articulated hitch and relevant running gear by their actual criteria, retaining repair history and the required scope.

Compare repair and movement scope with productive output

Check tires, axles and transmission against condition and service evidence. Ask what material and routes the truck has worked and use that history to guide inspection rather than predicting condition from meter hours alone. Itemize immediate repairs separately from future wear allowances, with each scope and its costs counted once.

For moving between sites, identify the supported travel or hauling configuration and any dismantling or separate components. Confirm mass, dimensions, loading and route permissions for that package. A class-wide claim that every articulated truck fits a lowboy or every rigid truck is dismantled cannot plan the actual move.

Compare complete offers on the same expected production and availability assumptions. Include road preparation and maintenance, fuel, tires, service, repairs, staffing and waiting as appropriate. A nominal payload increase can leave the operation constrained by the loader, road or dump point rather than reducing cost per tonne.

Off-highway truck model references

Use the exact designation in the linked section. Some reference groups include different generations or related machine arrangements; check the individual model and source before applying a figure to the offered equipment.

John Deere: haul-truck references

CASE: haul-truck references

Cat: haul-truck references

JCB: haul-truck references

Komatsu: haul-truck references

Volvo: haul-truck references

Hitachi: haul-truck references

Doosan: haul-truck references

Liebherr: haul-truck references

Terex: haul-truck references

Link-Belt: haul-truck references