Rear-Loading Hydraulic Garbage Truck Body Manufacturers: How to Compare Capacity, Payload and Compaction

We explain how to compare rear-loading hydraulic garbage truck body manufacturers by calculating how much waste a completed vehicle can carry per trip and collect during a working day. For municipalities and waste collection contractors, these calculations connect the body specification to the actual collection workload.

At BDB Metal, we manufacture garbage truck bodies with hydraulic compaction systems for municipal and commercial collection operations. If you are looking for a rear-loading hydraulic garbage truck body manufacturer, we recommend comparing proposals around three connected figures: usable body volume, available waste payload and the compacted density of your waste.

A larger body provides more storage space. Whether it carries more tonnes depends on the completed vehicle’s weight limits and the waste being collected.

Body Volume and Waste Payload Measure Different Things

Body volume, expressed in cubic metres, describes space. Waste payload, expressed in kilograms or metric tonnes, describes the mass the completed vehicle can carry within its applicable limits.

A 22 m³ body does not automatically carry 22 tonnes of waste. To convert volume into mass, we need the density of the waste inside the body.

Waste mass from volume, in tonnes = usable body volume in m³ × compacted waste density in kg/m³ ÷ 1,000

For an illustrative 20 m³ usable volume and a compacted density of 400 kg/m³:

20 × 400 ÷ 1,000 = 8 tonnes

This is the mass that would occupy that volume at the assumed density. The vehicle must also have sufficient payload capacity to carry it.

We therefore calculate the capacity-based load per trip as:

Load per trip = the lower of volume-based waste mass and allowable waste payload

If the volume calculation gives 8 tonnes but the completed vehicle can carry only 7 tonnes of waste, the payload limit governs the load.

When comparing manufacturers, ask whether the quoted volume describes the main storage body, includes the loading hopper, or represents another measurement. Hopper volume should not automatically be added to transport capacity; use the manufacturer’s confirmed usable storage volume and operating instructions.

Calculate Payload from the Completed Vehicle’s Operating Weight

The chassis, body and fitted equipment all consume part of the vehicle’s available gross weight.

For an initial calculation:

Gross-weight-based waste payload = applicable gross vehicle weight limit − ready-to-work vehicle mass

The ready-to-work mass should include the chassis, installed body, bin lifter, hydraulic equipment, operating fluids, fuel, crew and carried equipment. We recommend checking the weight basis carefully: chassis specifications can exclude fuel or the driver, so a published chassis weight may require adjustments before it is used in a payload calculation.

Illustrative Payload Calculation

The following figures are assumptions for explaining the calculation. They are not specifications for a BDB Metal model or a particular chassis.

The calculation is:

26,000 − 16,500 = 9,500 kg, or 9.5 tonnes

Each item must be counted once. If the installed body weight already includes hydraulic oil or the bin lifter, adding those items again would understate available payload.

The gross-weight calculation is only one check. The completed vehicle must also remain within applicable axle limits, chassis ratings and equipment ratings throughout loading. An axle can reach its limit before the total vehicle reaches its gross weight limit.

For the final comparison, we recommend obtaining a completed-vehicle weight breakdown and load distribution calculation. Our garbage truck dimensions and container compatibility guide covers the related dimensional considerations.

Compaction Ratio Connects Loose Volume to Compacted Density

Compaction reduces the volume occupied by a given mass of waste. It does not increase the vehicle’s allowable payload.

The volume-based compaction ratio is:

Compaction ratio = loose waste volume ÷ compacted waste volume

If 60 m³ of loose waste occupies 20 m³ after compaction, the ratio is 3:1.

For the same waste mass, with no material loss:

Compacted density = loose density × compaction ratio

For example, a loose density of 120 kg/m³ and an achieved compaction ratio of 3:1 give:

120 × 3 = 360 kg/m³

In a 20 m³ usable body, that would correspond to:

20 × 360 ÷ 1,000 = 7.2 tonnes

These are illustrative assumptions. We would use measured waste and operating data to establish the density for a purchasing decision.

Do Not Apply Compaction Twice

If you already have a compacted density of 360 kg/m³, multiply it directly by usable body volume. Multiplying the result by the compaction ratio again would overstate capacity.

We also recommend asking manufacturers how a quoted compaction ratio was established: which waste composition, starting density, loading method and test conditions were used?

Waste composition, moisture and compaction affect density. Truck-compacted density and landfill-compacted density also describe different conditions and should not be used interchangeably.

For practical planning, weigh representative loads and record how fully the body was occupied. A weighbridge gives waste mass; estimating in-body density also requires a defensible estimate of occupied volume.

Identify Whether the Vehicle Is Limited by Volume or Weight

We can calculate the density at which the available payload would be reached with a full usable body:

Threshold density in kg/m³ = allowable waste payload in kg ÷ usable body volume in m³

For a 20 m³ body with an allowable waste payload of 9,500 kg:

9,500 ÷ 20 = 475 kg/m³

Below this density, the body would generally fill before reaching that payload. Above it, the payload would be reached before the usable volume was fully occupied, assuming axle and other limits permit the calculated load.

All values in this table are illustrative.

This explains why a higher compaction ratio can improve collection capacity for one route and provide little additional transport benefit for another. Once the allowable payload is reached, further compression cannot justify adding more waste.

Compare Body Proposals on the Same Calculation Basis

When comparing rear-loading hydraulic garbage truck body manufacturers, we recommend requesting enough information to calculate the result for your intended chassis and waste stream.

A comparison using only cubic metres can favour a larger body even when the larger installation leaves less payload available.

Consider these hypothetical proposals, both assumed to satisfy axle and equipment limits:

Proposal B has approximately 22% more usable volume, but at this assumed density its capacity-based load is only about 5% higher. The remaining volume cannot be used to carry additional mass beyond its payload limit.

We use this type of calculation to make the comparison relevant to the collection task.

Convert Load per Trip into Daily Trips and Vehicle Requirements

Per-trip capacity is the starting point for fleet planning. We also need the daily waste quantity and the time available to collect and deliver it.

First:

Required loaded trips per day = daily waste quantity ÷ planned average load per trip, rounded up

Suppose a service area generates 48 tonnes per day and the planned average load is 8 tonnes:

48 ÷ 8 = 6 loaded trips per day

We define a loaded trip here as collecting a load and delivering it to the receiving facility. The planned average load should reflect route data; a calculated maximum does not mean every route will achieve that load.

Next, estimate a complete collection-and-delivery cycle:

If each vehicle has 7 usable operating hours after breaks, checks and other allowances:

Completed cycles per vehicle = 7 ÷ 3.5 = 2 per day

The working vehicle requirement is then:

6 required loaded trips ÷ 2 trips per vehicle = 3 working vehicles

Under these assumptions, each vehicle collects 16 tonnes per day and three vehicles collect 48 tonnes.

This is an illustrative capacity calculation, not a customer case study. Route geography, collection stop density, traffic, unloading queues and facility opening hours must support the schedule. We would also assess maintenance cover and peak-day demand separately from the three working vehicles.

Test Changes in Waste Density and Cycle Time

A small change in operating assumptions can change the fleet requirement substantially.

If the achievable average load falls from 8 tonnes to 6 tonnes:

48 ÷ 6 = 8 loaded trips per day

At two trips per vehicle, the requirement rises to four working vehicles.

If instead the full cycle increases from 3.5 to 4 hours, two cycles no longer fit within the assumed 7-hour operating window. The schedule must be recalculated before relying on two daily trips.

We recommend testing both lower-density waste and longer disposal turnaround times when comparing proposals. This shows whether the planned service has enough capacity on less favourable days.

Bring the Calculation into Your Manufacturer Enquiry

At BDB Metal, we manufacture garbage truck bodies for waste collection operations. To discuss a rear-loading hydraulic body for your fleet, send us the intended chassis specification, waste stream, expected daily tonnage and available operating hours.

Include representative load weights and disposal turnaround times where available. These inputs help connect body volume and installed equipment weight to the collection capacity your service needs.

You can review our garbage truck body range before preparing your enquiry. The useful comparison is the resulting tonnes per trip and tonnes per working day, supported by the completed vehicle’s loading limits.

Frequently Asked Questions