A tractor has two weights, and they are thousands of kilos apart
Ask what a tractor weighs and there are two honest answers. One is what it weighs standing empty. The other is the most it is allowed to weigh once fuel, ballast, a loaded implement and a driver are on it. Adverts, spec sheets and forum posts all say “weight”, and they do not always mean the same one.
What are the two weights?
| Figure | What it is | What it decides |
|---|---|---|
| Unladen mass | The tractor as it stands: no ballast, no implement, nothing added | What you are moving and lifting. Transport on a trailer. The starting point for ballasting |
| Permissible maximum mass | The most the machine may weigh, fully loaded, without exceeding what it was designed and approved for | Whether your ballast, loader and mounted implement together are inside the limit. Axle and tyre loads |
| Operating mass | A working weight in some particular state, which the source has to define to mean anything | Little, unless you know exactly what was on the machine when it was weighed |
The third is the one to be careful with. “Operating weight” without a stated configuration is not a specification, it is a number: it could include a full tank and a loader, or neither.
How far apart are they?
Far enough to matter. Of the 3,122 tractors on the site, 3,122 carry an unladen mass and 1,185 carry a permissible maximum. We hold both figures on 1,185 machines, and on 1,184 of those the maximum is the larger of the two, which is the only case a headroom figure can be read from. On those 1,184:
- The middle machine may carry about 2,400 kg more than it weighs empty.
- Half of them fall between 1,590 kg and 3,410 kg of headroom.
The other one is the interesting case: Schlüter S 450 (S 450 V) carries a permissible maximum that is not above the unladen mass. That is impossible on a real machine — it would be over its own limit standing empty — so the two figures are not the pair they look like, and we leave it out of the arithmetic rather than averaging it in. It is on the list to be re-read against the source.
That headroom is not spare capacity to be spent casually. It is the budget that fuel, ballast, a loader, a mounted implement and the driver all come out of — and it is shared between the axles, each of which has its own limit.
When does the difference actually bite?
- Putting it on a trailer. You need the unladen mass, plus anything still bolted to it. Read the maximum instead and you will buy far more trailer than you need; read it the other way round and you may overload one you already own.
- Fitting a loader. The loader, its frame and whatever it lifts all come out of the headroom, and most of it lands on the front axle.
- Ballasting for traction. Adding weight is how you put power on the ground — up to the point where the machine is at its limit, and past that it is simply overloaded.
- Road use. What you may take on a public road is governed by the rules where you are, not by the tractor’s own maximum. They are two different tests and both have to pass.
What does WhichTractor publish?
Whichever of these a source states, stored as its own field and labelled on the page — never merged into one “weight” row. Where a source gives a figure without saying which weight it is, that is what the page says. We do not convert one into the other, and we do not estimate a maximum from an unladen figure: the gap above describes the machines we hold, it is not a multiplier to apply to yours.
For your own machine the plate and the operator’s manual are the authority. If a figure here disagrees with them, the manual wins — and please tell us.