Is 4 x 2000 kg jack capacity enough for the weight of my caravan?
2000 kg per jack, 8000 kg in total, is a load capacity and not a lifting figure. Decide on the maximum laden mass on the plate and the load distribution.
The load capacity of the D3501-1142 jack is 2000 kg per jack, and 8000 kg in total over four jacks. That figure is not the weight at which the whole caravan can be lifted into the air; it shows the limit of the share of load falling on the jacks while the wheels stay on the ground. So make the assessment on the maximum laden mass on the plate of the caravan and on how the load is distributed inside the vehicle.
What 2000 kg means and what it does not
The most frequent mistake in the capacity question is to take the total of 8000 kg for a lifting capacity. The correct reading is this: each jack has a load capacity of 2000 kg. Since the wheels stay on the ground during levelling, only a part of the weight of the caravan is transferred to the jacks and the rest goes down to the ground through the axles. Jack load capacity is a figure given for a vertical and static load; forces coming from the side are a separate matter.
The steps of the assessment
- Take the maximum laden mass on the plate of the caravan as the basis, not the unladen weight.
- Assume that the load is not distributed evenly between the jacks; the water tank, the batteries and the kitchen are generally concentrated on one side.
- If the ground is sloping or soft, the share falling on a single jack rises; using a plate that increases the contact area lowers the ground pressure.
- Like every piece of equipment fitted afterwards, the levelling set is deducted from your payload capacity; the maximum laden mass must not be exceeded. How much the set takes from that allowance is dealt with under a separate heading.
- In a layout where all four jacks do not bear on the ground at the same moment and with the same firmness, the load can gather on two jacks; check this by eye at first commissioning.
The simplest way in the field of telling whether the load really is on the jacks is to look at the wheels once the levelling is finished: if the tyres are still squashed, most of the weight is on the axles, and if a wheel has come free, most of the share has passed to the jacks. In the second case, retract the jacks a little and level the vehicle again.
Field situations that strain the capacity
| Situation | Effect on a single jack | Precaution |
|---|---|---|
| Ground sloping sideways | The jacks on the low side take most of the share | Move the vehicle to as level a spot as you can |
| Soft ground, sand, gravel | Even if the capacity is enough, the jack sinks into the ground | Use a foot plate |
| Load gathered on one side | One jack is loaded several times as much as the others | Redistribute the stowage |
| Asphalt softening in the heat | The limit is not the jack but the strength of the ground | Use a wide-based plate |
Where capacity on its own is not enough
- The strength of the chassis. Even if the jack carries 2000 kg, the point it is fixed to may not; whether reinforcement is needed depends on the structure of the vehicle.
- Jack stroke. A jack that falls over a hollow does no work if it cannot reach the ground, whatever its capacity; look at that when choosing the parking spot.
- Variable loads. Wind and people moving about inside change the load from moment to moment; capacity is a static figure.
- Use for lifting. Do not use the jacks for changing a tyre or for underbody maintenance; that is a job for a jack and axle stands.
- The links other than the jack. The weakest place in the chain is often not the jack but a bolt, a plate or the chassis sheet; the capacity figure does not cover all of those.
If you are in doubt, consult your caravan manufacturer or an authorised project engineer for a load distribution calculation. And in every case do not lift all the wheels off the ground; jacks do not take the place of the parking brake, and chocks have to be used.
The full topic: How to choose levelling jack capacity