Towing a Balanced Caravan
Towing a balanced caravan is a daunting, if not, seemingly impossible task for new caravanners. It is hard to tow a caravan. We find a large number of caravanners have been advised to install load levelling devices.
Caravan load levellers or weight distribution hitches were initially believed to be the best device on the market to balance caravan connections. Further, installing load levellers on the caravan drawbar was previously recommended by caravan outlets only because they were the best solution available at the time.
However, I have never been a fan of load levellers, as I have found they mask problems with an unbalanced caravan and can cause a problem with excess weight being loaded onto the vehicle suspension. Drivers are often unaware of the new weight limits being loaded on the tow bar by the load levellers.
As a result, the maximum towing capacity a vehicle can legally tow has been exceeded, with excess downforce or weight on the vehicles tow bar.
Couplemate have recently manufactured our own tow ball scales in response to one of the most common questions we get, “how do I balance my caravan?” Our new scales measure the weight of the caravans coupling or the camper trailer coupling.
Here is a tip – carry your weight scales on board (they weigh less than 2kg) and measure the coupling head weights once every week of your trip. This measurement provides excellent information on how the dynamic balancing of your caravans affects the way you drive it.
An unbalanced caravan without the right correction equipment can lead to disastrous consequences like the caravan rollover reported on 7 News . For more on this story, click this link.
In this case, an unbalanced caravan commenced a sway event that a driver was unable to rectify.
How do I balance my caravan loading weights?
Balancing a caravan is not as hard as you would imagine.
- Measure the front and back wheel arch to the ground (write these measurements down).
- Measure the tow tongue height to the ground (these first two measurements are the reference points to review once you have reached point 5).
- Connect your caravan to the vehicle and swing up the jockey wheel.
- Do not engage the load levellers.
- Now remeasure points 1,2 and 3.
- If you have a level, put it on your drawbar. The bubble should be centred. It will point slightly down once the weight is shifted to the tow bar (when connected).
- Now your caravan drawbar is level, measure the distance between the bottom of the coupling head and the top of the tow ball tongue. The correct distance is the shank height or 12mm (there are some variations, for example, if your height is at 25mm then installing a 2mm shackle tow ball is your solution).
- You may need to change your receiver bar to a drop bar or riser bar to correctly match your tow bar with your caravan.
Once your caravan is balanced in a level towing position, the final thing we need to balance is the coupling head weight. You will need to purchase a tow ball scale as a result of varying coupling head weights during your trip. We will cover this later in the post.
Coupling Head Weight Balancing
It’s equally important to ensure you are balancing your coupling head weight correctly. Follow the simple instructions below to make sure you avoid uneven load:
- Write down the ATM from your VIN plate or alternatively take your rig over a weighbridge. Leave your trailer connected, but ensure you drive your vehicle off the scale (leaving only the caravan to be weighed).
- Collect your weighbridge ticket then drive home and finished the rest of the procedure.
- Once home, disconnect the caravan from the towing hitch.
- Insert the tow ball scale into the coupling.
- Wind down the jockey wheel to insert the full drawbar weight onto the ball scale.
- Single Axle head weight is approximately between 7% – 10% whereas tandem approximate head weight is between 5% to 7% (please note: no lighter than recommend and no heavier than towbar manufacturer recommendations).
- Add scale weight to weighbridge weight to get the actual ATM.
- Alternatively, you can multiply the ATM by the % for single or tandem axles to get your approximate coupling head weight.
- With the coupling head weight known you can now move weight forward to to the rear of your caravan to balance your rig.
Caravan and trailer coupling head weight has a massive effect on towing and vehicle suspension.
An unbalanced caravan can cause your front suspension to lift causing a light front end, subsequently reducing traction and steering.
Remember, I asked you to measure the front and rear wheel arches? Once you have balanced your rig these wheel arches will be within manufacturers specifications.
A light front end causes oncoming traffic to experience high beam rays coming from your vehicle at night.
How many times have you noticed oncoming traffic using high beam and not dipping their headlights?
It is likely these travellers have an unbalanced caravan that has lifted the front suspension.
Finally, a light front suspension also increases the likelihood of a sway event similar to the video above. It’s critical to ensure the weight of your rig is well-adjusted.
Balancing Trailer and Caravan Weight
Gas bottles and toolboxes add significant amount fo heavyweight to the front drawbar or A-frame area.
In an effort to counterbalance these weights many caravanners have loaded spare tyres and other heavy items onto the rear of the caravan.
The very best place to store heavy equipment is over the axles or the vertical centre of gravity. Once the free space is exhausted over the axle area with heavy items, it is necessary to balance your rig front and back.
Balancing a caravan is a similar concept to balancing a set of scales.
However, you must follow the weight distribution rules
- allowing 5% – 7% of the ATM on the coupling for tandem
- or 7% – 10% of the ATM on the coupling for single axles
Why is there a variation in percentages?
Single axles have less resistance to the road surface in a sway event, therefore, more force is required on the coupling to prevent sway. The lighter end of the scale applies when your rig is empty, the upper end when your rig is full of water, food and essentials.
Tandem axles have more resistance to the road surface than single axle caravans. As a result, they are more resistant to sway at the same speeds and loading, than similar rigs in a single axle configuration.
Electronic Sway Controllers
Even with a perfectly balanced caravan, unforeseen events can occur resulting in disasters – take a kangaroo jumping out in front of your vehicle, while highway towing.
A balanced caravan is perfect in normal driving conditions however, electronic sway control will straighten your rig in an instant during potential unexpected events.
BMPRO sway control overrides your brake controller in a sway event by apply power directly from the battery to left tor right side where necessary.
The result of a sway event is the caravan or camper trailer will brake directly in the line of travel and cause the tow vehicle to decelerate. Once the sway event has finished, the sway controller returns to its normal monitoring position.