6 Tips For Using A Public Weighbridge With Your Car
Many people mistakenly assume that overloading their vehicle is only going to add some extra dollars to their petrol bill. There are, however, some more serious consequences. An overloaded vehicle is not only illegal, it’s unsafe because its handling ability and braking distances can be compromised. It also means that the car is working harder, which puts it at risk of premature wear and an increased risk of mechanical failure.
The easiest way to ensure that your car isn’t overloaded is to head to your local public weighbridge. Here are a few tips to help you use a weighbridge effectively:
1. How to measure Tare Mass, Kerb Mass and Gross Vehicle Mass (GVM)
Tare Mass is the weight of an empty standard vehicle, Kerb Mass is the weight of an empty standard vehicle with a full tank of petrol, and GVM is the maximum weight allowed when the car is fully loaded. These are the easiest things to measure — simply drive onto the public weighbridge, stop when all wheels are on the deck and record the weight.
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2. How to measure Gross Vehicle Axle Mass
This is the individual maximum weight allowed for a car’s front and rear axles. For a single deck weighbridge, drive onto the deck and stop only when the front wheels are on the scale. Record the weight. Then drive forward until only the rear wheels are on the scale. Record the weight. Multi-deck weighbridges can make this easier, as you only stop once.
3. How to measure Tare Trailer Mass and Gross Trailer Mass (GTM)
Tare Trailer Mass is the weight of an empty trailer/caravan, and GTM is the maximum axle weight allowed for a trailer/caravan. Tow your trailer or van onto the weighbridge, wind down the jockey wheel to support it and disconnect it from your car. Ensure that the jokey wheel is on the same deck as the trailer/caravan, then record the weight.
4. How to measure Tow Bar Download (TBD)
This is the amount of vertical weight your trailer/caravan exerts on your car’s tow bar. Position your vehicle (whilst connected to the trailer/van) so that its wheels are on separate decks and record its weight. Then disconnect the trailer/van and record the weight of the car. The difference between the two weights is the TBD.
5. How to measure Aggregate Trailer Mass (ATM)
This is the Gross Trailer Mass (GTM) plus the Tow Bar Download (TBD) — in other words, the maximum towing weight allowed for the trailer/caravan. Once you’ve established the GTM and the TBD, simply add the two values together. We know that all of these acronyms can be confusing, so sorry if we’ve lost you!
6. How to measure Gross Combination Mass (GCM)
This is the maximum weight allowed for your tow vehicle combined with a trailer/caravan. This is measured by positioning the connected car and trailer/van on the same deck of the public weighbridge and recording the weight it spits out. If they’re too long to fit on one deck, simply combine to the two weights to get the GCM.
Now that you’re aware of the dangers of overloading your vehicle, we hope that the tips provided above have enabled you to accurately use a public weighbridge to determine the maximum weights. Do not hesitate to ask for assistance if required; depending on what weighbridge you visit, you may find that there is a staff member on duty who can help you set everything up correctly. Once you know the maximum weight, it’s essential that you don’t exceed it.
