Whenever people inquire about the five specifications of a crane, I always respond with the following comment:

“Ensure you always have the rated lifting capacity, the maximum operating radius, the maximum lift height, tail swing radius, and boom length checked.”

This is because these five specifications will determine whether a crane is suitable for the job on site. Whenever you are comparing various models, these are the specifications to consider.

What Are the 5 Specifications of a Crane And Why They Matter?

What is the working arm of a tower crane?

Rated Lifting Capacity — “Can it lift the load?”

This is the first spec that we all look at, but it is also the most misunderstood.

The max lifting capacity of the crane depends on various factors.

For instance, when the load is not close to the crane, or the boom is extended beyond the maximum distance, then that “25-ton crane” may only have the capability to lift a few tons.

This number is basically your go or no-go safety line. (read more: What is a Load Moment Limiter for Tower Crane and How Does It Work?

Maximum Working Radius — “How far can it reach while lifting?”

The working radius is how far the center of the crane is from the hook.

The larger the radius, the weaker the crane.

This is where the majority of mistakes happen.

If your load is sitting behind a fence, pipe rack, or retaining wall, the radius expands—sometimes without people noticing—and the crane suddenly becomes under-rated for the lift.

Max Lifting Height — “How high do you need the hook to go?”

We’ve seen a few people get this wrong.

The lift height will always be different from the length of the crane boom.

Factors such as boom angle, extensions, and the lift block will all impact your height.

When you’re on a high wall, lifting onto a rooftop, or reaching over structures, this spec is more important than anything else.

Tail-Swing Radius — “Can the crane physically fit in the job site?”

Let’s imagine you’ve found a perfect crane that has the perfect job and the perfect lifting capability. But wait, does that crane even have a proper safe radius malfunction?

Tail-swing radius informs people how much space the back end of the crane needs during rotation.

In tight job sites — factories, power plants, construction sites on the road, and space between two buildings — this spec can literally decide if the crane can even get on the job site.

Boom Length — “What’s the real working range?”

Having tall structures and long horizontal reaches, boom length becomes a major deciding factor.

  • Boom length defines your height and radius potential.
  • Longer boom length also reduces lifting capacity.
  • Always think of it as the crane’s work envelope.

As your boom length increases, so does the height of your lift and the reach of your lift.

How These 5 Specifications Interact

Tower Crane

No spec among a crane’s specs works in isolation. They affect each other. That’s where inexperienced planners fall into a trap.

  • Long boom → More reach but less lift capacity
  • Greater radius → Safe lift weight drastically lowers
  • Add a jib → More height, less capacity
  • Large tail swing → More space required on job site
  • Just because it’s high capacity on paper doesn’t mean it’s high capacity at a long radius.
Job Site ScenarioCritical ParameterPotential Risk PointWhy Problems Occur
Lifting inside a factory/workshopTail-Swing RadiusInsufficient crane slewing spaceThe counterweight tail collides with pipelines or equipment
Lifting materials on roofs / exterior wallsMax Lifting Height + Boom LengthHeight available but not “effective height”Low boom angle results in insufficient vertical reach
Long-distance liftingWorking RadiusLifting beyond the rated radius capacityActual capacity at the working radius is far below the required load
Heavy equipment liftingRated CapacityOnly looking at “maximum lifting capacity”The rated load drops sharply as the radius increases
Compact jobsites / city streetsTail-Swing RadiusThe rated load drops sharply as radius increasesRequires a small-tail or zero-tail-swing crane

5 Specifications of 10 Commonly Used Cranes

Potain tower crane
Crane ModelRated Lifting CapacityMax Working RadiusMax Lifting HeightTail-Swing RadiusBoom Length
Tadano ATF 600G-8600 t~104 m~147 m15.2–56 m
Tadano ATF 400G-6400 t86 m125 m15–60 m
Tadano ATF 220G-5220 t84 m107.5 m13.2–68 m
Grove GMK5130-1130 t~56 m~61 m4.36 m6-section main boom
Liebherr LTM1095-5.195 t54 m58 m3.78 m6-section boom
Liebherr LTM1130-5.1130 t56 m60 m4.20 m6-section boom
Liebherr LTM1100-5.2100 t66 m84 m3.84 m11.5–52 m
Demag AC 100-4109 t44 m77 m12–59 m
Grove GMK409090 t3.5 m51 m + jib
Liebherr LTM1060-3.160 t48 m63 m48 m boom

Summary

  • Rated Lifting Capacity — tells you if it can actually lift the load
  • Working Radius — tells you how far it can reach
  • Lifting Height — tells you how high above the ground it can place the load
  • Tail-swing Radius — tells you if it will physically fit on your job site
  • Boom Length — tells you the overall working envelope and coverage

These five specs give you a realistic view and understanding of a crane and what it can do. Then you are able to benchmark the claims made in a manual.

These numbers have a strong interconnection and relation to each other. Once you can sort that out, it will be easier to compare crane models. Then you will be able to pick the most efficient and safe machine that is suitable for your line of work.