The information here is based on a motorhome conversion of a commercial chassis but it holds true for virtually any vehicle.
VIN stands for Vehicle Identification Number.
It's a unique 17 digit number which includes coded information such as Country of Assembly, the Manufacturer, the Body Style and Engine, and the year of build. The last 6 digits are the vehicle's serial number and when all are combined, it's the unique 'fingerprint'. It should be stamped in the chassis but may also be found around the engine block, the driver's door jamb and probably in the boot.
Additionally, it should be stamped on a VIN plate (usually located just under the
bonnet) and the plate will also show various weights.
When a vehicle has been converted or modified (i.e. campervans/motorhomes) the converter will add there own plate or sticker which may modify the weights.
It's vital you understand your vehicles VIN plate. Exceeding ANY ONE of the listed weights is an offence.
What weights are shown? From top to bottom in the example shown is the MAM (Maximum Authorised Mass), GVW (Gross Vehicle Weight) or MGW (Maximum Gross Weight) followed by GTW (Gross Train Weight) or GCW (Gross Combined Weight).
The numbers 1. 2. and 3. are axle weights. 1. is the maximum allowable weight of the front axle. 2. is the maximum allowable weight of a single rear axle. 3. is the maximum allowable weight of a third or 'tag' axle.
Axle weights added together should exceed the GVW which allows for some margin in the way the vehicle is loaded.
What weights are NOT shown? The VIN plate will not show the unladen or kerb weight, the payload, the towing limit or the towbar noseweight.
The unladen or kerb weight should be in the vehicle handbook. However, to be sure, have the vehicle weighed on a weighbridge. The difference between the unladen weight and the MGW is the maximum allowable PAYLOAD.
The towing limit can be calculated by deducting the MGW from the GTW. The resulting figure is assuming that the vehicle is fully laden. In the event that the full payload isn't being used, the balance can be added to the calculated towing limit.
The towbar itself should have a type approval sticker which shows a 'D' value and an 'S' value. The 'S' value quite simply is the maximum allowable noseweight. The 'D' value is rather more complicated and is a calculation based on the GVW and the maimum towing limit. I shall cover this in another blog.
REMEMBER! 1. Do NOT exceed any of the weights on the VIN plate.
2. Check your driving licence categories and limits to ensure you are legal!
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