Calculating the effects of Ball Weight
Your car and tow bar has a maximum tow ball weight. Whichever is the lesser, is the maximum amount of load you can place on your tow bar when hooking up a trailer (caravan, camper or box).
But, what does that weight really mean when you look at the bigger picture of loads on the tow vehicle (sometimes called the ‘tug’).
Luckily, we can turn to Archimedes (born in 287 BC) and his teachings in regard to levers.
Imagine if you had a shovel of dirt with the handle horizontal, and the handle end of shovel was held in your left hand. If you wanted to lift that dirt, its effective load would be ‘increased’ depending on where you held the shovel with your right hand but it will always be heavier than the weight of the dirt itself. This is known as a ‘third-class’ lever.
To continue the analogy with the shovel, if you move your right hand towards the dirt it will become easier to lift; and if you try to lift nearer the handle end of the shovel it will be much more difficult.
We can see then too, that:
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- if you get rid of some of the dirt (reduce the ball weight) the loads will be less;
- if you make the handle longer (get a car with a longer wheel base) the leverage will be improved; and
- if you move your hand closer to the dirt (reduce the overhang) the leverage will also be improved.
LoadGood Calculator
To pull all this together in one place, LoadGood steps you through the impacts of the trailer ball weight on the car’s rear axle.
In addition to determining the adjusted weight on the car’s rear axle by adding or changing a trailer ball load, LoadGood will also calculate the adjusted loads on the trailer and car’s axles and ball by adding, removing and moving loads in, and on, your vehicle and/or trailer.
Even if you don’t know the actual loads, you can still have a fiddle with some hypotheticals to see how your car loads are affected by these ‘levers’.
As you will soon see, 350kg on the ball can be significantly more when you look at its affect on the rear axle. This may be an amount greater than what you have left to play with when the car is loaded.
LoadGood also gives you a multiplier for your car that you can use as a quick ready-reckoner in your head.
You can even use this calculator as a tool when doing your research before you buy a new car or trailer.
Hitch Campers has a great blog which is worth reading on loading tips.
Please let me know how you go. I’ll be interested in your feedback.
