Chassis Design

Posted on January 8th, 2008 in Driving Emotion,Materials,Opinion by Julian Edgar

Imagine you were living in the late 1930s (and of course, a very small number of you may well have been!). Then, as now, cars had four wheels, a body, engine, suspension and brakes. But they often had something else as well – a chassis.

Nowadays, nearly all cars use monocoque construction, where the pressed steel body provides the required stiffness. The main exceptions are traditional off-road four-wheel drives and trucks and buses – these vehicles still largely use a separate chassis. A few bespoke cars also use non-monocoque construction; for example, a tubular space frame.

But even in the late 1930s, you could have seen plenty more designs that just a traditional chassis. Have a look at these – all are taken from The Mechanism of the Car, written by Arthur W Judge and published in 1939.

vauxhall.jpgFirstly, we have monocoque (or unitary) construction. This Vauxhall retains a separate bolt-on chassis for the front suspension and engine mounts, an approach common in cars up to the 1970s.


amilcar-1.jpgBut then we have the cast aluminium frame. What?! Yes, a car being sold in 1939 (the Hotchkiss Amilcar) used a frame formed from cast aluminium members bolted together.


Here’s how the cast alloy frame integrated itself into the car.


austro-daimler.jpgThen there was the tubular frame, as used by Austro-Daimler. The very large diameter central tube would have given both high bending strength and also resisted torsion.


And finally, we have a car that’s absolutely intriguing – and one I’d never heard of before. It’s simply listed as the ‘MG Racing Car’ and uses a backbone chassis formed from pressed, welded plate. The car also features double wishbone suspension front and rear – perhaps the first car to ever do so.

I think that these drawings are worth looking at closely (you can click on them to enlarge). In mechanical car design, there’s very little new under the sun…

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  1. Ron Hughes said,

    on April 10th, 2008 at 10:11 pm

    Is it still legal to pop rivet a chassis together & would it still need to be x-rayed