Thursday, Oct 26, 2017 at 22:04
I've calculated that, with a slide on camper on an alloy tray, plus all the gear and other add-ons, we should come in at about 200 kg below the GVM
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There are plenty of examples on the net of cars
well under GVM that have still bent their chassis. It is not the weight that does it, it is mass ( the material in something ) and where that mass is located in the car. Slide ons are the worst offenders because all of them weigh so much when empty. By the time you put a few things into them, they are usually way over the car's limit for loads right down the rear end.
As an example of mass and the forces generated by mass in motion, place a brick carefully on top of an ordinary drinking glass. The glass should not break. Pick the brick up about 100 mm and drop it onto the glass and the glass will shatter. The weight of the brick did not increase but the material in it fell building up momentum as it went down and the glass was unable to withstand the impact when it tried to bring the brick to a sudden stop. That is what the end of a car chassis is trying to do with the material that is sitting on it.
If you are making these
suspension alterations to support the load on the rear end then the car must be overloaded. The standard
suspension does not need any assistance to support the load it has been designed to support.
The DVD in the link below shows what excessive but slow motion leverage applied to the end of a chassis in cab/chassis vehicle can do to the chassis. It was pulled down by the cable running down from the top of the jib. Too much heavy material sitting
well back behind the rear axle will do the same thing when the end of the chassis has to constantly lift it suddenly or stop it falling suddenly, particularly when the back of the car is rising and falling when the car is being driven on unsealed roads.
When you see ARB, ask them to explain how their suspensions move heavy material further forward and how it supports the far end of the chassis when the back can go down and the front of the car lifts up. The rear axle is a pivot point in situations like this and
the springs just compress and tilt with the chassis.
Tow truck
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