In this guide to levelling your caravan and tow vehicle for safe towing, we discuss why being level matters, how to check if it’s level, the easiest way to level up your rig and whether you should consider a weight distribution hitch.
Getting your vehicle and caravan level is essential for safe towing, and getting it right when hitched up depends on several factors. However, we are not going into that oft-trundled remedial effort, a Weight Distribution Hitch (WDH). Sure, the WDH has its place, but if you haven’t set up the rig so it is level in the first place, a WDH is just a band-aid solution.
Let’s start with why getting your vehicle and caravan level matters!
Why being level matters
Why do you need to have the vehicle and van level anyway? Balance. Bear in mind that a level rig is only one part of a heady combination of factors that make up a safe, balanced rig.
A caravan wheel set acts like a fulcrum or pivot point. So, if the van is nose-up when hitched, there is too much weight on the back of the van, resulting in poor towing dynamics. The back of the van will act as a pendulum, with the excess weight in this area causing the trailer to move from side to side.
When you have the opposite level situation – the caravan is in a nose-down stance when coupled up – the weight of the van will have shifted too far forward, and this is also a recipe for a sway situation developing. This is magnified in the case where there’s a high tow ball download. That can cause the tow vehicle to lift too much at the front, reducing the balance and front tyre grip and therefore not only increasing the chance of sway but reducing the ability of the driver to steer and brake effectively.Â
Another problem with the nose-down or nose-up attitude on the caravan is poor aerodynamics. Caravans are, by their very nature, not the most aerodynamic of things. But with the frontal area altered by the incorrect balance, they can become even less aerodynamic, increasing the tow vehicle’s fuel consumption.
How to check if your vehicle and caravan are on the same level
So, how do you go about ensuring your vehicle and caravan are level? Start by making sure you’re not buying something mismatched like a tall off-road caravan hitched up to a low-passenger vehicle or a large vehicle hooked up to a road-going pop-top.
First off, you need to measure the caravan. With the van parked, uncoupled and on level ground, get a spirit level and place it on a horizontal part of the van such as the A-frame. Next, adjust the jockey wheel until the spirit level indicates that the caravan is perfectly level. Confirm this by measuring one of the longitudinal chassis members at the front and then the rear of the van to ensure that the measurements are the same.
The caravan coupling and vehicle towball can now be measured to see if they are at the same height level. It is difficult to get an exact, identical measuring point on the coupling and tow ball, but a good point on the coupling is at the lowest lip of the 50mm coupling assembly and then on the corresponding point on the tow vehicle’s tow ball.
If your uncoupled heights have a difference of more than about 100mm, it suggests you may have a problem with getting your vehicle and caravan level. If you have measured the vehicle and van before buying either, you are in the fortunate position of considering whether you might need to go with another vehicle/van combination. We’ll get to what you can do about it shortly if you’re already sold on the combination or already own the rig.
Let’s get a bit more technical
According to Vehicle Standards Bulletin 1 (VSB1), the centre of the coupling must measure between 350mm and 420mm from the ground when the trailer is coupled to the tow vehicle. However, if your uncoupled measurements are outside of these, don’t worry about it yet because you’ll establish if you’re legal once you’ve hitched up the van.
Before hitching up the caravan to the vehicle, check the static suspension height of the tow vehicle. Measure from the centre point of the wheel or the lowest part of the rim to the lip of the wheel opening for both a front and rear wheel on the same side of the vehicle.
Then, hitch up the van, repeat the measurements on the vehicle, and check you do not have more than about 25mm droop at the rear or 25mm rise at the front.
With the caravan hitched, check your spirit level and measure the chassis rails again. A small difference in measured caravan chassis rail height (depending on the length of the van but say about around 30mm) won’t have a significant effect on balance, but if you see a difference of 50mm or more, it indicates a problem — time to do something about it.
The easiest way to level up your rig
The easiest way to fix the level problem on your vehicle and caravan is to change the towbar tongue to an aftermarket one with an adjustable height position.
When filming “Are You RV Safe?“, we used an adjustable height ball mount kit supplied by TAG to ensure we were able to get both the tow vehicle and caravan on the same level and ensure safe towing. You can see it in use in Episode 3 on 10Play.
With an adjustable towbar tongue set at what appears to be the correct height, you may still have unacceptable rear suspension droop (more than 25mm) on the tow vehicle. In this situation — as long as the tow vehicle’s front body rise measurement is no more than about 30mm — you need to establish whether the towball download is excessive by either measuring it with a dedicated towball download scale or at a public weighbridge.
If the towball download is around seven to 10 per cent of the van’s weight, then all you may need to do is fit stiffer rear springs, or airbag helper springs to the tow vehicle to level it out. If the tow vehicle’s nose is pointing towards the sky and you have a high TBM, then you need to consider repositioning the load in the caravan and vehicle so that it is better balanced. Every vehicle and van combination is different, so again, get independent expert advice to see what will work best in your situation.
Should you use a weight distribution hitch?
The Weight Distribution Hitch (WDH) has taken on a mythical status in some Australian caravanning circles as the only safety item that guarantees your rig won’t sway its way into a rollover. Some would suggest it would be suicidal to tow without one fitted.
While there is a place for the WDH, it is not the cure-all some suggest it is. Why? Because a WDH exerts enormous forces on the caravan and vehicle chassis, especially on the vehicle towbar. In many cases, the caravan needs to be better balanced or is just too nose-heavy for the tow vehicle.
In all cases, a WDH’s spring bars must be slackened before negotiating deviations in road surfaces such as spoon drains or steeply angled driveways, or it will impose loads on the vehicle and van it was not intended to impose, and that can cause damage.
If your caravan has a high towball download (more than around 250kg, or more than 15 per cent of total caravan weight), then you still have to ensure your rig is level, using the steps mentioned earlier, before attaching a WDH.
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