TOP GEAR GAVE US A CLUE
If you have ever watched Top Gear , you may have heard host Jeremy Clarkson talk about the issues with car manufacturers turning ordinary sedans into convertibles . In his assessment , when you remove the roof from a sedan , you take away much of its structural integrity . To fix the issue , manufacturers have to strengthen the base chassis . They do this by adding extra bracing to the frame . This not only adds considerable weight to the vehicle but it never really cures the inherent sloppiness in the chassis and the resulting vehicle doesn ’ t handle as well as the sedan equivalent .
Third-class Lever
This diagram shows how the rear of a ute forms a third-class lever .
How to improve the efficiency of a third-class lever
If you look at any dual-cab ute , you will see that is it two ‘ vehicles ’ built on a single chassis . The front is like any sedan and the back is similar to a convertible . It ’ s a big open tub without a roof and , unlike a 4WD station wagon , there is nothing connecting the two halves except the chassis itself . This creates a natural weak point where the chassis can flex and , under certain circumstances , bend .
ARCHIMEDES , LEVERS AND A COAT HANGER
The Greek mathematician Archimedes once said , “ Give me a lever long enough … and I will move the world .” The rear half of a dual-cab ute can be described as a third-class lever where the fulcrum ( or pivot point ) is located at the point along the chassis where the two halves of the ute meet . The effort to lift the load is provided by the suspension and the load is located along the other side of the chassis . You can see what I mean in the diagrams on this page .
You can improve the situation by either moving the load or moving the force .
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