How to Choose RV Levelling Jack Capacity
The combined load capacity of the jacks must exceed the loaded weight of the RV. Even though the jacks do not lift the vehicle clear of the ground, load distributes unevenly on sloped terrain and a single jack can carry more than expected.
The rule is simple: the combined load capacity of the four jacks must be well above the loaded weight of the RV. This margin is necessary even though the jacks do not lift the vehicle fully clear of the ground, because the load does not distribute equally across four jacks and a single jack can see more force than calculated.
Which weight should be used?
Not the empty weight — the loaded weight is what counts: water tank full, gear stowed, gas bottles fitted. Using the maximum laden weight from the registration document is the safest approach.
Why isn't a quarter of the load enough?
Arithmetically, a 3,500 kg RV puts 875 kg on each jack. In reality, however:
- The center of gravity is usually near the axle; the rear jacks are loaded noticeably more than the front jacks.
- Differences in ground firmness can concentrate the load on a single corner.
- On sloped ground the distribution becomes even more uneven.
For this reason the industry selects total capacity at a multiple of the vehicle weight. For example, a four-jack set rated 2,000 kg per jack gives 8,000 kg total; for an RV in the 3,500 kg class that means roughly a 2.3x safety margin. Skimping on jack capacity means the system operates at its limit exactly when it matters most — on the steepest ground.
Note: There is no standardized, citable table for minimum capacity per jack. The approach above is an engineering rule of thumb; the final selection must be made according to the capacity declared by the manufacturer and the actual load distribution of the vehicle.
What happens if capacity is exceeded?
The motor is overloaded, current rises, and current protection trips to stop the motion. Without protection there is a risk of mechanical damage — which is why a system with hardware current protection should be chosen.
Why does the ground matter?
Even with adequate jack capacity, on soft ground the jack sinks into the soil and levelling is lost. On grass, sand, and wet soil a load-spreading pad must be placed under the jack. The pad spreads the same force over a wider area and prevents sinking.
Stroke distance
Alongside capacity, how far the jack can extend is also decisive. On very steep ground the capacity may be sufficient while the stroke is not. Industry guides are blunt about this case: instead of forcing the system, move the vehicle to flatter ground or reduce the starting slope with blocks.
For the full picture on this topic: RV Automatic Levelling Guide: Why It's Needed, How It Works