Mobile crane outriggers and counterweight systems
A mobile crane's capacity rests on two things: the counterweight that balances the load and the outriggers that carry it all to the ground. How both work, and why pad sizing is a calculation.
6 min read · 2026-07-28
Everything a mobile crane can lift depends on two systems most people never look at: the counterweight at the back that balances the load at the front, and the outriggers that lift the whole machine off its wheels and carry its weight, plus the load, down into the ground. Get either wrong and the rated capacity on the chart becomes meaningless. The counterweight has limits set by what can be transported and what the ground can take, and the outriggers concentrate the entire load onto a few small pads, which is exactly where many lifts come undone. Understanding both is understanding why a crane is stable, or why it is not.
This guide is grounded in how these systems work and why pad sizing is a calculation.
Balance at the back, support at the base
The counterweight balances the load; the outriggers carry the combined weight to the ground. The rated chart only holds if both are right.
Counterweight: balancing the load
The counterweight is what lets a crane hold a load out at radius without tipping forward. Every crane carries one, and the chart capacities assume a specific counterweight configuration is fitted. There is a practical ceiling on how heavy it can be, set by what can be transported to site and by what the ground will bear, so adding capacity is not just a matter of more weight at the back.
Outriggers and pads: carrying it to ground
The outriggers transfer the crane's weight and the load onto the ground through pads. Because the contact area is small, the pressure under each pad is enormous, so pads are used to spread that load over a larger area and bring the ground bearing pressure down to a safe level. The pad size needed is a simple division: the maximum outrigger load divided by the allowable ground bearing pressure gives the area required.
| Element | Role |
|---|---|
| Counterweight | Balances the load to prevent tipping |
| Outriggers | Lift the crane off its wheels onto a wide base |
| Pads | Spread the outrigger load to safe ground pressure |
| Ground assessment | Confirms the ground can carry the pad pressure |
Load / GBP
the pad area calculation
Small pad
huge pressure beneath
Counterweight
set by the chart config
Ground
must carry the pressure
Setting up for stability
- 1
Fit the right counterweight
Match the counterweight to the lift chart configuration.
- 2
Deploy outriggers fully
Extend to the planned footprint and level the crane.
- 3
Size the pads
Divide the outrigger load by the allowable ground pressure.
- 4
Assess the ground
Confirm the ground carries the pad pressure with a margin.
Pad sizing is a sum, not a guess
Reusing a standard pad without checking the outrigger load against the ground pressure is how cranes settle and tip. The pad area is calculated for the lift, not assumed from habit.
Every crane we set up has its counterweight, outriggers and pads sized to the lift and the ground. Tell us the lift and the site and we will plan the setup with it.
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