Wednesday 4 August 2021

Improved shock absorbers

 The front Shockers

The car on track was still not handling correctly in my opinion, despite upgrading the brakes and steering with added caster angle. My track times at Forrestburn are well off the pace for a properly sorted car.  The problem occurs when there is an abrupt change in camber. The Bowden suspension has an inherent design defect in that the front springs change length under load. This causes bump instability. The steering direction does not change but the tow in/out changes dramatically which is translated by the camber change into bump steer as one side is loaded up on a corner and the other has little grip anyway.

Tony Betts markets a conversion kit for the standard front axel on an Austin Seven to separate the shockers (from each side) and shorten the friction arms.

  As you can see from the following image when this assembly is overplayed on a Bowden arrangement it is about 180mm short on both sides.

The following cardboard model illustrates the type of modification required on my car.

Hopefully I should be able to sell some of the bits when I am finished.

This diagram shows the difference between the two mounting plates

The lower CAD drawing was uploaded to a company in Glasgow (Kilbarchan) called JetCut. The part was cut out of 5mm thick stainless and posted out to me. Some holes were relieved in the fabrication to keep the weight down. The rt angle was welded in ss by myself.

The above image shows the final arrangement installed in the new front suspension arrangement.

The final test was on the track see Video

Here is an Index page for the build

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