HIAB cranes and lorry loaders are one of the most common types of crane on UK roads. They sit behind the cab on flatbed trucks and use outrigger legs to stabilise before lifting. The pads under those outriggers matter more than most operators realise.
Why HIAB Pads Get Overlooked
Most lorry loader operators inherit whatever pads came with the truck. Often that is a pair of battered timber blocks or thin steel plates that came from the previous owner. Some trucks have nothing at all and the operator just deploys the legs straight onto the ground.
The problem is that a HIAB crane can put serious point loads through its outrigger feet. A 10 tonne metre crane does not sound like much until you work out the actual force going through each leg during a full extension lift. On soft ground, tarmac driveways or freshly laid surfaces, that force is enough to punch straight through without a proper pad underneath.
How Much Load Are We Talking About?
As a rough guide, a lorry loader lifting near its maximum capacity at full extension can push 3 to 8 tonnes through a single outrigger leg. That is concentrated on an outrigger foot that might only be 150mm x 150mm. Without a pad, the ground pressure under that foot can easily exceed 1,000 kN per square metre. Most garden driveways, grass verges and footpaths are rated at 50 to 150 kN per square metre.
What Size Pad for a HIAB?
For most lorry loaders up to about 20 tonne metres, a 400x400mm or 500x500mm pad in 40mm thickness covers the majority of ground conditions. If running a bigger lorry loader or regularly working on soft ground, step up to a 500x500x50mm or 600x600x40mm. Use the table below as a quick reference, then check with the calculator if you want a specific confirmation.
| HIAB / Lorry Loader Size | Recommended Pad | Ground Type | Shop |
|---|---|---|---|
| Up to 10TM | 400x400x40mm Flat | Firm ground, tarmac, concrete | View Pad → |
| 10 to 20TM | 500x500x40mm Flat | General use, mixed ground | View Pad → |
| 10 to 20TM (soft ground) | 500x500x50mm Recessed | Soft ground, grass, gravel | View Pad → |
| 20TM+ | 600x600x40mm Flat | Firm ground | View Pad → |
| 20TM+ (soft ground) | 800mm Round Premium | Soft or variable ground | Browse Round Pads → |
Enter your crane capacity, outrigger load and ground type. Get a specific pad recommendation from our range.
400x400x40mm pad. Handles most standard deliveries on firm ground.
500x500x40mm or 500x500x50mm. Good all-round choice for mixed ground conditions.
600x600x40mm or larger. Required for soft ground or heavy lifts at reach.
If in doubt, go one size up. The extra cost is small and the extra safety margin is worth it every time.
Why UHMW-PE Beats Timber and Steel
Lorry loader pads need to be light enough for one person to grab off the truck, tough enough to handle daily use on rough ground and small enough to store on the vehicle. UHMW-PE ticks all three boxes.
A 500x500x40mm Essential pad weighs under 10kg. A timber block the same size would weigh more, absorb water, split after a few months of outdoor storage and need replacing. Steel plates are heavier still and slide on wet surfaces. UHMW-PE does not absorb water, does not rot, does not corrode and does not crack in freezing temperatures.
Do I Actually Need Outrigger Pads on a HIAB?
Yes. Every time the outriggers go down, pads should go under them. It is not just about protecting driveways and surfaces, although your customers will appreciate that. It is about crane stability.
BS 7121 requires that ground conditions are assessed and adequate load spread is provided for any crane operation. That includes lorry loaders. If an outrigger sinks, the crane loses its stable base and you are into a potential overturn situation. On a truck mounted crane next to a public road, that is as serious as it gets.
Carrying Pads on the Truck
Most lorry loader operators store pads on the flatbed or in the chassis tool box. Our Essential Range pads are sized specifically for this. A pair of 500x500x40mm pads will fit in most standard truck storage compartments. The recessed carry handle sits flush so they stack flat without snagging on other kit. If you carry four pads for the full set of outrigger legs, that is under 40kg total weight for the 500mm size.
Get the Right Pad for Your HIAB
Browse our Essential Range or use the Pad Size Calculator to find the right pad for your lorry loader. All sizes in UK stock with next-day delivery.
