Why do weights matter?
Excess or poorly distributed weight can result in reduced rig performance, but it’s important to know that this can also lead to far greater consequences. It could mean a rollover accident, invalidated insurance and/or result in sizeable fines or license penalties.
We are here to help you understand the terminology and what it means for your set up.
Safety: An overloaded or unevenly loaded setup may mean that steering and braking are compromised. Stability may also become an issue, creating the risk of sway or rollover. Correct weights (within manufacturer specifications) will improve your overall safety on the road and protect your passengers and yourself.
Legality: If a vehicle or tow combination is found to fall outside of manufacturer specifications, it is illegal. It may be prevented from travelling further, except by tow truck. This situation may also increase the risk of significant fines for the driver. Finally, it may invalidate insurances and compromise payment of related claims on both car and caravan/trailer.
Money: A car or van that is overweight or has poor weight distribution, will certainly cost more to run. It may increase fuel costs, reduce tyre life, reduce brake life and create expensive wear on other moving parts. Staying within manufacturer’s weight limits will reduce the chance of mechanical or structural failure, both of which are extremely costly.
Weights, explained
While learning about weight compliance can be over whelming, we are here to make the process as simple and straight forward as possible.
Commonly asked questions
What are the relevant laws?
Laws relating to vehicle and caravan compliance and towing vary slightly from state to state (or territory). The vehicle licensing laws state that cars and tow balls must be roadworthy and operate within manufacturer’s specifications at all times. Tyre, towball and hitch ratings must not be exceeded.
There are specific laws relating to maximum towing speed and the use of towing mirrors. Further clarification about regulations and consequences for noncompliance can be found on individual State, Territory and Federal websites.
Can you weigh fifth wheelers?
Our scales are rated to 12 tons (in 1 kg increments) and can weigh the heaviest of fifth wheelers and caravans with ease.
The hitch weight is determined differently for a fifth wheeler. We weigh the van hitched and then unhitched, the difference between the two figures being the equivalent to Towball Mass. This number will be higher that the percentage value expected with hitched caravans, because the weight sits directly above the rear axles.
Should I weigh loaded or unloaded?
We recommend always weighing a fully loaded caravan, where this is practical. This ideally includes water tanks full, grey water tanks full, gas bottles full, fridge stocked, clothes and personal items on board. It should also include any tools, BBQ, chairs, annexe and other ‘locker’ items you would normally travel with. Once we have been able to determine where the ATM/GTM sit, it will be clear whether there is extra capacity or not for packing the car and/or caravan.
Can you determine tow-ball weight?
Yes, there are two main ways to calculate ball weight of a trailer or caravan accurately. We use a dedicated, professional tow ball scale, which weighs the Towball Mass and gives a KG result. Using cheap DIY towball scales can give inaccurate figures without constant calibration.
The other method (which is less accurate) is to calculate the ATM (Aggregate Trailer Mass or unhitched weight) and then weigh the van again when unhitched (Gross Trailer Mass). The difference between the two figures will give an approximation of the Towball Mass.
How do I know what my van/vehicles limits are?
Your tow vehicle must comply with manufacturer’s specifications. These will include Gross Vehicle Mass, Gross Combined Mass for towing, Towball Mass, Axle Group Ratings and individual axle ratings.
This information can be found on a compliance plate on the vehicle, usually located on the inner door frame or engine bay. With a caravan or trailer, it is usually on the chassis or in the front hatch. The same information can also be found on the manufacturer’s website, via a Google search. Finally, it should also be specified in an owner’s manual, if you have one.
How long does it take?
Our weighing times vary depending on the what we are reporting on. To get an idea of timing for your service, please view the ‘service’ tab of the website.
What do you include in the report?
The report will feature an easy read summary page, with clearly indicated results for the key weight metrics that impact safety and legality. These include GVM, GCM, BTC, individual weights for both wheels and axles for the car. The trailer and caravan metrics include ATM, GTM, Axle Group Loadings and Towball Mass. There will also be a section in the report specific to the vehicle and another for any towable.
These acronyms can be confusing, so we provide a graphic resource that provides descriptions for common weights acronyms. All results will show whether there is compliance and any variations (over or under). Our team will go through the report with you, making sure you understand and offering advice to improve weight issues such as distribution.
How can I change/reduce/upgrade my limits?
Weight limits can be increased by a certified engineer in some states, with a new certification and compliance plate being issued.
Alternatively, a GCM/GVM upgrade can be achieved using a professional organisation such as Pedders or Lovells, who will strengthen and re-engineer components.
If such an upgrade is too expensive, the alternative is to reduce mass by taking payload out of the car and/or caravan. Redistributing weight between car and caravan may also be helpful.
All measurements and values provided in Drive A Weigh reports are accurate at the time of weighing. Drive A Weigh takes no responsibility or liability for fluctuations in weight as a result of changes made by the customer (eg. additional loading to the vehicle and/or trailer). Any advice given, verbal or written, is for guidance only.