I have received an interesting reply from SPAX:
"We are aware with the issues relating to bump steer on this car. Early cars had a longer rack the later cars had a shorter rack which has some effect. I have driven various cars and some are simply better than others. Having spoken to various people in the know which say the tracking makes a sizeable difference to how they behave regardless of rack etc. The first cars built had non European dampers supplied by suplex (spring manufacturer) and these had a spring on the outside as you'd expect and a spring inside of the damper.. Spring manufactures like this idea!. The idea was to limit vehicle lean using the internal spring in the damper to control the dampers extension. In practice it creates a step change in spring rate which can not be matched with step changes in damping rate. Good predictable handling always comes from smooth transitions of force/ geometry etc. Step changes in forces does not.
I have done more development on the 3 wheeler since the fixed rate dampers where designed, and we have developed a Morgan approved upgrade path. These are available from Aeroracing, I can't find them on there website which seams out of date, you may need to call them.
What we supply is a ride hight adjustable, damping rate adjustable kit for this car which makes a good difference to control wheel and body movement while retaining comfort. The spring rates are the same as we fit on the fixed rate dampers since these are in my view correct for the car. The rear springs are a shorter to keep the spring seats away from the belt. Naturally you can adjust the ride hight but be careful not to run out to suspension travel. With the adjustable dampers you can set the stiffness to where you feel is acceptable in the comfort/ performance compromise although the compromise was not significant. The damping characteristics are also different in the way they build force with shaft speed, we was able to give more low shaft speed control while keeping the high speed damping low enough to retain comfort. One of the development cars was a car local to Spax Hq, the owner was very pleased and even his co-driver (wife) noticed the improved stability and improved ride comfort which was very pleasing.
The front dampers on this car have to be quite special and we build them with a unique valving since the car is fairly unique and the motion ratio is such that the damper only moves 0.4" for 1 inch of wheel movement."
