What the load center is
Every forklift capacity rating carries a hidden assumption: how far the load's center of gravity sits from the fork face. In most of the world that assumption is 500 mm; many North American and heavy-duty ratings use 600 mm. A standard pallet holding a dense, evenly distributed load puts its center of gravity near the geometric center, and at or near that assumed distance the truck delivers its nameplate capacity.
The moment the center of gravity sits further out — a long load, an attachment pushing the load forward, a pallet loaded unevenly with heavy items at the front — the effective capacity falls. The truck does not lose strength; it loses leverage balance, and the rated figure simply no longer applies.
Why the number moves capacity so fast
A counterbalance forklift is a seesaw: the load on one side, the counterweight and truck mass on the other. The tipping moment is weight times distance. Doubling the distance doubles the moment at the same weight, so a load rated comfortable at 500 mm can overload the same truck at 750 mm even though nothing about the truck changed.
This is why capacity charts show derated figures at increasing load centers rather than a single number. The nameplate figure is not a property of the truck alone; it is a property of the truck-and-load-center combination, and buyers who quote capacity without the load center are quoting half a specification.
| Load center | What it means in practice | Effect on rated capacity |
|---|---|---|
| 500 mm | Standard pallet, dense even load — the global rating assumption | Full nameplate rating applies |
| 600 mm | Common on North American and heavy trucks; bulky but even loads | Rating assumes the longer arm; check which basis a chart uses |
| 600–750 mm | Long or awkward loads, double-stacked pallets, unusual cargo | Effective capacity falls below nameplate; use the derated chart figure |
| Beyond chart range | Very long loads or attachments | Truck selection itself is wrong; move to a larger class or different equipment |
Where buyers get caught
Three situations produce most load-center surprises. The first is long or awkward cargo: a buyer moves from palletized goods to long profiles, bundles or crates whose center of gravity sits far forward even when the weight is trivial. The second is attachments: a side shifter moves the load slightly forward, and clamps or rotators move it much more, which is why attachment selection and residual capacity must be read together — our guide to choosing attachments covers the residual-capacity mechanic in depth. The third is uneven loading: a pallet with dense goods stacked at the front edge behaves like a longer load than its dimensions suggest.
Each of these is invisible on a purchase order that says "3.0 ton forklift". None of them is invisible to the truck on its first shift.
How the Granvolt line is rated
Our electric counterbalance line is rated at 500 mm: the EP18 at 1,800 kg, the EP25 at 2,500 kg and the EP30 at 3,000 kg, with load charts available for longer centers. The diesel line follows the same convention — the DF30 at 3,000 kg @ 500 mm and the DF50 at 5,000 kg @ 600 mm — and the rough-terrain RT40 carries 4,000 kg @ 600 mm. When you send an RFQ, we ask for your heaviest pallet and its load center rather than a target tonnage, because that is the question the truck will actually answer. The capacity selection guide walks through that worksheet in order.
A practical sizing method
- Identify the heaviest pallet that will ever be lifted, including packaging and seasonality.
- Estimate its true center of gravity — for even pallets, half the load depth; for uneven ones, weight the front third.
- Add attachment offset if any attachment will be fitted.
- Read the derated capacity at that combined load center, not the nameplate number.
- Keep a margin for the worst realistic pallet, not the average one.
The method takes fifteen minutes and replaces the most common sizing error in the industry, which is buying by tonnage nickname and discovering the gap on the first difficult pallet. Fleet buyers who standardize this worksheet — load center, attachment offset, margin — consistently end up with trucks that match their real work, and the load chart guide shows how to read the manufacturer chart once the numbers are in hand.
Frequently asked questions
What does 500 mm load center mean on a forklift?
It means the rated capacity applies when the load's center of gravity sits 500 mm from the fork face — the assumption behind most standard pallet ratings. If the center of gravity sits further out, the effective capacity is lower than the nameplate figure.
How much capacity do I lose at a 600 mm load center?
It depends on the truck and its load chart; the loss grows with distance and with how close the truck runs to its stability limit. Read the derated figure on the manufacturer's load chart at the actual center rather than applying a fixed percentage.
Do attachments change the load center?
Yes. Attachments add their own weight ahead of the forks and move the load's center of gravity forward, so effective capacity falls by more than the attachment's own weight. This is called residual capacity.
Is load center the same as load height?
No. Load center is horizontal distance from the fork face; load height affects stability separately and appears as its own curve on the load chart.
What load center does the Granvolt EP30 use?
The EP30 is rated 3,000 kg at a 500 mm load center, with derated figures available for longer centers on request through the load chart.