The problem with going to a public weighbridge to determine exactly what your caravan weighs is that you might want to return home and repack your gear to change how your rig is balanced – but you'll have no idea what the affect was.
Clearly you could go back to the weighbridge each and every time you shifted the weight around, but for most caravanners, that is not an enticing proposition. The time, fuel and weighbridge ticket costs are not worth repeating for this exercise.
The solution is to do your own ball weight measurements. There are a few ways of doing this. The most common you hear about is using the old, faithful bathroom scales. The positives of doing so include the fact it is convenient – most people own such scales – and cheap, as you don’t have to buy anything.
The negatives are that unless you know that your ball weight is likely to be low, the bathroom scales won’t read the ball weight other than to tell you it weighs off the scale (of about 130kg, roughly the limit of most bathroom scales).
Also, the newer glass bathroom scales are more easily broken unless you’re really careful, and the faithful steel scales you’ve had for years – and have relied on to lie about your weight – will faithfully underestimate your caravan’s ball weight, too.
But there is another solution. I have read all about the way in which you can use bathroom scales and cut up some timber and make a pivot point to halve the weight taken by the scales. This solves the problem of having a heavy ball weight (well, up to around 260kg, at least) and bathroom scales that are limited to around 130kg.
The trouble is that those who use this setup could probably just as well calculate the ball weight plus/minus one per cent by doing a few mathematical equations. It’s easy if you know what you’re doing, or very easy to get completely wrong if you don’t know what you’re doing.
There must be an easier way…
The easier way is actually throw away the timber, put the scales back in the bathroom and buy a dedicated ball weight scale. These scales are portable and relatively inexpensive.
A word of caution: you’ll need to have a level surface to park your van on, make sure the van’s park brake is on and that wheels are chocked. Lower the van’s coupling onto the scale, until the jockey wheel is raised clear of the ground. Do not take the jockey wheel off the van or swivel it up – if the scales do tip over, you’ll want the jockey wheel there to prevent the van from landing on its A-frame.
The only thing to be careful of when using these sorts of measuring devices is that, because they typically don’t have a wide base, the van could tip over if not level. The bonus is, of course, instant ball weight measurement, relatively fuss-free.