How to Choose the Right Crane Capacity for Your Project

Choosing crane capacity starts with the lift, not with a tonnage label. A 25-ton, 50-ton or 70-ton crane cannot lift its maximum rated load at every boom length or working radius. For a buyer, the correct capacity is the smallest crane class that can perform the required lift within the manufacturer's rated load chart while fitting the jobsite and setup conditions.

Before selecting a used crane from Japan, confirm the actual load weight, working radius, hook height, boom requirement, available outrigger space and ground conditions. Then compare suitable crane models using their exact load charts. This guide is for contractors, plant operators and overseas machinery buyers who need a practical way to decide what crane capacity their project really requires before comparing individual used machines.

Do Not Start With “I Need a 25-Ton Crane”

A request such as “I need a 25-ton crane” is incomplete.

The more useful questions are:

• What is the heaviest load?
• How far is that load from the crane?
• How high must it be lifted?
• How much boom length is required?
• Can the outriggers be fully extended?
• What is the ground condition?
• Will a jib be required?

A crane's maximum lifting capacity usually applies only under a limited combination of boom length, radius and setup.

As the working radius increases, available lifting capacity normally decreases according to the manufacturer's load chart.

The Five Numbers You Need Before Choosing Crane Capacity

Before comparing models, collect five basic figures.

1. Load weight
2. Working radius
3. Required lifting height
4. Available outrigger width
5. Available working space

If one of these is unknown, your crane selection is still incomplete.

1. Determine the Real Load Weight

Start with the actual suspended weight.

This is not always the same as the weight of the main object.

The total suspended load can include:

• The object being lifted
• Hook block
• Slings
• Shackles
• Spreader beam
• Lifting frame
• Other rigging equipment

The correct calculation depends on the crane manufacturer, load chart and rigging arrangement.

Do not guess the load weight from appearance.

Use reliable manufacturer data, drawings, certified weight information or another appropriate method.

2. Measure the Working Radius

Working radius is one of the most important crane-capacity factors.

It is generally the horizontal distance between the crane's center of rotation and the vertical line through the suspended load, according to the relevant crane definition and load chart.

A small increase in radius can materially reduce rated lifting capacity.

This means a 20-ton load close to the crane can require a very different machine from the same 20-ton load positioned much farther away.

A Simple Example: 30 Tons Does Not Mean 30 Tons Everywhere

Kato's SR-300LX provides a clear example.

The manufacturer lists a maximum lifting capacity of 30 t × 3.0 m.

However, its official load information changes as boom length and working radius change.

Therefore, “30-ton crane” describes the machine class. It does not mean the machine can lift 30 tonnes throughout its working area.

3. Determine the Required Lifting Height

The next question is how high the hook must reach.

Consider:

• Height of the structure
• Height of the load itself
• Rigging length
• Required clearance
• Hook block position
• Obstacles between the crane and load

A project may have a moderate load weight but require a longer boom because the lifting point is high.

In this case, boom length rather than maximum tonnage may become the limiting factor.

Hook Height and Boom Length Are Not the Same

Do not assume that a 30 m boom provides exactly 30 m of usable vertical hook height.

Actual geometry depends on:

• Boom angle
• Boom pivot height
• Hook block
• Working radius
• Jib configuration

Use the manufacturer's working-range diagram rather than a simple boom-length number.

4. Check Whether You Need a Jib

A jib can extend lifting height or reach beyond the main boom.

However, jib lifting capacity is normally much lower than the crane's maximum main-boom capacity.

For example, a rough terrain crane rated at several dozen tonnes on its main boom may have jib capacities of only a few tonnes depending on angle and configuration.

If your project regularly requires jib work, compare jib charts before choosing the crane.

5. Measure the Available Outrigger Space

Outrigger width can completely change the crane selection.

A model may have excellent rated capacity at full outrigger extension but much lower capability at an intermediate setting.

Tadano explains that working areas and rated lifting capacities can change according to outrigger extension width and slewing direction.

Kato's SR-300LX, for example, provides five outrigger positions from fully retracted to 6.6 m fully extended.

This flexibility can be valuable on restricted jobsites, but the correct load chart must be used for the selected position.

Never Assume Full Outrigger Extension Is Available

Before buying a crane, inspect the actual project area.

Check for:

• Walls
• Road traffic
• Buildings
• Excavations
• Stored materials
• Other machinery
• Property boundaries

If the crane cannot extend its outriggers as required by the intended load chart, the larger theoretical capacity may not be usable.

Ground Condition Is Part of Crane Capacity Planning

A crane needs a stable supporting surface.

The required setup depends on the crane, load, outrigger reactions and ground conditions.

Before selecting a machine, consider:

• Compacted soil
• Concrete
• Asphalt
• Fill material
• Soft soil
• Sloped ground
• Nearby excavations

Ground bearing capacity and proper outrigger support require qualified site planning.

A crane's rated capacity does not remove the need for a suitable foundation under the outriggers.

Crane Capacity Is Different From Crane Stability

A crane may have enough theoretical lifting capacity but still require a setup that the site cannot safely provide.

Capacity selection must therefore consider:

• Rated load chart
• Outrigger configuration
• Ground support
• Level condition
• Manufacturer operating requirements

The machine cannot be selected from load weight alone.

How Much Extra Capacity Should You Buy?

There is no universal percentage that makes a crane automatically “safe.”

Do not simply add 10%, 20% or 50% and assume the result is correct.

The correct crane should meet the required lift in the manufacturer's rated-capacity chart under the actual planned configuration.

Additional practical margin may be desirable for changing site conditions or future jobs, but this is a business and lift-planning decision rather than a substitute for the load chart.

Why Buying the Largest Crane Is Not Always Better

A larger crane can provide more lifting capacity, but it also brings other requirements.

• Higher purchase cost
• Higher transport cost
• More weight
• Larger tires
• Greater fuel use
• More setup space
• Potentially wider outriggers
• Higher maintenance cost

If a smaller crane safely performs the work, the larger machine may add cost without improving productivity.

Why Buying Too Small Can Cost More

An undersized crane creates a different problem.

You may discover that:

• The required radius is too long.
• The main boom is too short.
• The rated capacity is insufficient.
• The jib cannot handle the load.
• Full outrigger extension is impossible.

This can make the crane unsuitable for the project even though its maximum tonnage looked sufficient when purchased.

Think in Terms of Load Chart Performance

Instead of comparing “25t vs 30t vs 50t,” compare this:

Small Rough Terrain Crane Classes

Smaller rough terrain cranes can be practical where:

• Loads are moderate.
• Access is restricted.
• Jobsites are compact.
• Transportability matters.
• Required radii are relatively short.

As one current example, Tadano's Japanese lineup includes a GR-160N with 16.0 t maximum lifting capacity.

That figure alone does not confirm suitability. The load chart still determines the actual usable capacity.

25-30 Ton Class

This class is common for a wide range of construction and industrial lifting jobs.

Current examples include the Tadano GR-250N and Kato SR-300LX.

The Tadano GR-250N uses a 9.35–30.5 m main boom.

The Kato SR-300LX also uses a 9.35–30.5 m main boom and is rated at 30 t × 3.0 m.

Even though their boom ranges are similar, buyers should not assume their capacity charts are identical.

50-70 Ton Class

This range can make sense when:

• Loads are heavier.
• Working radius increases.
• Greater boom length is required.
• Industrial lifting is more demanding.
• A smaller crane lacks useful capacity at the required radius.

Examples in Japanese-brand rough terrain cranes include Kato SR-500 class machines and Tadano GR-600N or GR-700N models.

The correct model depends on the actual lift rather than the nominal tonnage.

100 Ton Class and Above

Larger rough terrain cranes become relevant for heavier industrial and infrastructure work.

Tadano's current Japanese GR-1000N, for example, is a 100-ton class crane with a 10.2–48.0 m main boom.

This larger class also brings greater transport, site-space and ownership requirements.

Do not select it merely for additional reserve capacity if the project cannot use that capability economically.

Compare Crane Type as Well as Capacity

Capacity is not the only machine-selection question.

Different projects may require:

• Rough terrain crane
• All terrain crane
• Truck crane
• Crawler crane

A rough terrain crane is attractive for maneuverability and jobsite travel.

However, another crane type may suit longer road travel, very high capacity or different site conditions better.

This article focuses on capacity selection rather than choosing between crane categories.

Do Not Forget the Weight of Attachments and Rigging

Crane buyers sometimes focus only on the object being lifted.

Depending on the crane and chart, relevant lifting equipment can reduce the remaining capacity available for the actual load.

Always account for the complete lifting arrangement according to manufacturer requirements.

Wind and Weather Also Affect Lift Planning

Wind can affect suspended loads and crane operation.

Large panels, tanks or other loads with significant surface area can create substantial wind forces.

Weather limits should follow the crane manufacturer's requirements and applicable local regulations.

Do not solve a wind problem simply by buying a crane with a larger tonnage rating.

Check the Correct Load Chart on a Used Crane

For a used machine, confirm that the available load chart matches:

• Manufacturer
• Exact model
• Generation
• Boom
• Jib
• Counterweight configuration where applicable
• Outrigger configuration

Do not use a load chart from a similar-looking model.

Why the Serial Number Matters

Crane specifications can change within a model family.

The serial number helps identify the individual crane for technical documentation, parts and manufacturer information.

Before buying:

1. Ask for the model plate.
2. Record the complete model designation.
3. Record the serial or chassis number.
4. Confirm the boom and jib configuration.
5. Match technical documents to that crane.

Used Condition Still Matters After You Choose the Capacity

Choosing the correct crane class is only the first step.

After that, inspect the individual machine.

Important areas include:

• Boom condition
• Wire ropes
• Winches
• Hook block
• Outriggers
• Hydraulics
• Slewing system
• Safety system
• Tires
• Carrier brakes and steering
• Maintenance information

A correctly sized crane in poor condition may still be a poor purchase.

Operating Hours Do Not Tell You the Required Capacity

Operating hours help evaluate used condition, but they have no role in deciding how much crane capacity your project requires.

First determine the required crane class from the lift.

Then compare available used cranes by:

• Hours
• Mileage
• Maintenance
• Previous use
• Boom wear
• Hydraulic condition
• Safety-system condition

A Practical Capacity Selection Example

Suppose your project needs to lift equipment weighing 12 tonnes.

Do not immediately search for a 12-ton or 16-ton crane.

First determine:

• Will the load be 4 m or 15 m from the crane center?
• Does the hook need to reach 10 m or 30 m high?
• Can outriggers be fully extended?
• Is a jib required?
• What rigging weight must be included?

Only then can you identify a crane whose load chart covers the lift.

The answer could be very different depending on radius and height.

A Crane Capacity Selection Checklist

1. Load Weight: Confirm the real suspended weight.
2. Rigging: Account for hook block and required lifting gear.
3. Radius: Determine the maximum working radius.
4. Height: Determine the required hook height.
5. Boom: Identify the boom length required.
6. Jib: Confirm whether jib use is necessary.
7. Outriggers: Measure available extension space.
8. Ground: Confirm that a suitable setup can be prepared.
9. Load Chart: Check rated capacity at the actual configuration.
10. Crane Type: Confirm that a rough terrain crane suits the site.
11. Transport: Check dimensions and weight of the selected class.
12. Support: Confirm local service and parts availability.
13. Used Condition: Inspect the individual machine after selecting the class.

Buying the Right Crane Capacity from Japan

Japanese used machinery can include rough terrain cranes from Tadano, Kato and other manufacturers across multiple capacity classes.

You can check current Japanese used machinery available at EVERYCAR.jp. Stock changes regularly, so a particular crane size or model should not be assumed to remain available.

When making an inquiry, it is more useful to provide your maximum load, working radius, required lifting height, preferred crane type, budget and destination than to provide tonnage alone.

For broader guidance covering Japanese used cranes and other heavy equipment, visit the Japanese Used Machinery & Heavy Equipment Guide.

Choose the Smallest Crane That Can Perform the Real Lift Correctly

The right crane capacity is not simply the next tonnage above your load weight.

Start with the complete lift: weight, radius, height, boom, jib, outriggers and ground conditions.

Then use the correct manufacturer load chart to identify a crane class that can perform that lift within its rated configuration.

A crane that is too small may not perform the job. A crane that is much larger than necessary may increase purchase, transport and operating costs.

If you are looking for a used crane from Japan, you can contact EVERY with the maximum load, working radius, required lifting height, preferred manufacturer or crane type, budget and destination. Exact lifting capacity, load charts, configuration and condition should be confirmed for each individual crane before purchase.