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.
This diagram shows the difference between the two mounting plates |
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