BMW Dixi for sale

[Mike Costigan]

A smart 1931 DA4 BMW for sale in Austria - I think the DA4 model had independent front suspension, so the first Dixi to start the development away from the Seven.

https://www.prewarcar.com/584389-bmw-3-1...-verkaufen

   

[Peter Naulls]

Very smart. Press reports at the time suggest the new front suspension design made them even more "interesting" to steer than the standard Seven set up! The front spring was connected directly to the stub-axle assembly without the use of a rigid axle.

[Tony Griffiths]

All the same - but all very different. It makes one wonder if any parts would interchange with a 7 of the same year.

[Tony Press]

Very smart. Press reports at the time suggest the new front suspension design made them even more "interesting" to steer than the standard Seven set up! The front spring was connected directly to the stub-axle assembly without the use of a rigid axle.

Looking at the front view - how do the wheels stay upright- does the flexible end of the spring hold it in combination with the weak radius arm  ?

[Peter Naulls]

Yes, as far as I can make out the camber angle changes with deflection of the spring, hence the poor handling properties.

[Chris Garner]

BMW commenced production of a new swing front axle on 17th December 1930 and first sales commenced on 10th February 1931. These were built in parallel with the fixed axle variety but more swing axle models were offered than the rigid. viz: chassis, open 2-seater, tourer, saloon, coupé 2 and 4-seater cabriolet.
This new BMW 3/15 PS DA4 had other features - a shorter scuttle, and a more spacious body accomplished by the deletion of the luggage boot.

The swing axle was not without controversy particularly from Dipl.-Ing. Josef Ganz, the publisher of the Motor Kritik magazine. He argued that the camber angle changed when the suspension was compressed and this was dangerous. A fierce argument developed between the two parties. Initially BMW did not accept the criticism but did eventually made changes.

Of interest is that at this time sales were falling. BMW approached Austin requesting the agreed licence fees be reduced. Herbert Austin reacted angrily to this and in a five page letter pointed out all the errors he perceived that Dixi / BMW had made - design, price and too large factory premises. An argument ensued, but Austin stood his ground.
By the end of '31 compete cessation of vehicle production was seriously considered by BMW.

[Alan]

Hang on a minute, there may be more to this than meets the eye. Normally with swing axles the camber goes negative as the axle goes into bump. Here, as the stub axle rise the spring lengthens and with a clever bit of maths could cancel the camber change. Were they that clever? Who can say.

[Tony Press]

I would think this suspension would give camber, possibly caster, toe in and various other odd wheel movements- I assume the track rod had ball ends. 

[Chris Garner]

The enclosed may be of interest in better understanding the arrangement.        

[Robert Leigh]

That picture gives considerable enlightenment compared with the words in earlier comments. The arrangement appears to be such that camber changes would be insignificant, and deflection would only cause minimal change to toe-in.