Mobile weighing errors explained 

Hi Robert..great info thanks. I recently had my 4WD and caravan weighed. This is the second time and I used the same mobile weigh bridge firm. ( reason for another weigh was I purchased a new 4WD). In spite of moderate changes to my caravan ( lithium battery replacement from AGM ) there was a vast difference in the individual wheel weights on my caravan. In fact the front left hand wheel increased by about 160 kilograms. Notably the first weighing was done in my (flat) driveway at home, whereas the second at a local service station where there was a small slope probably 2 or 3 degrees placing the left hand wheels down the slope. This video no doubt shows why the variance occurred. Thanks again for the great article.

Good info, thanks!

Another important take away is scales will always register less.

I've tried to explain to people in recent years, but some don't want to hear...... These new fangled air hoses with two or four outlets. The idea is that you can inflate at tyres from the same compressor, all at the same time. The problem is that unless you are parked on a absolutely flat surface, you'll end up with different pressures in each tyre. Robert, perhaps you should do a video showing what I mean.

You don't need a cat to demonstrate this stuff but it doesn't hurt

In other words: Not enough of a difference to make a difference. All a bit academic.

Not sure the examples used with the cup are accurate. Firstly, ‘button’ scales don’t work like that, each time a button scale is moved it should be ‘tared’ on the new surface before weighing anything. Secondly, button scales should never be used for vehicle weighing, if an operator is using button scales for vehicle and caravan weighing….. RUN a mile!!! They have no place in the industry. Button scales are for weighing food, flour etc…. Where a static weight is placed in the middle of the weighing surface. This is why you’ll always see a butcher press tare before weighing your 1kg of sausages. All scales used for heavy vehicle weighing should use ‘shear beam’ load cells. Shear beam load cells talk to each other and take the average from all load cells on the pad, that’s why there is no difference in weight regardless of where a weight is placed on the pad. We can’t compare weighing practices using button scales v shear beam scales, it’s just not comparable as they are totally different and are made for different purposes. Button scales are for vertical compression only, they can’t handle slopes or gradients. Each time any scale is moved , weather it a button type scale or load cell, the scales should be recalibrated at the control box before the vehicle or caravan is weighed. This ensures the scale is zeroed on the surface used for weighing, this includes moving a scale a metre or 2, even if it’s the same hard surface. Errors in weighing are occurring because the industry has been over run by people buying scales and calling themselves ‘ experts’ after weighing 10 caravans. Especially when they don’t really understand how their gear works, it will be the downfall of the whole mobile weighing industry. I follow you closely and rate your content highly however, think you may have missed the mark on this video. Sorry to seam negative, this is just my 2 bobs worth.