Everything is a compromise, but in this case all the parts are fixed and we are trying to put into words what the eccentric inserts do as these are the only parts that can be changed, basically they increase trial for this set up, which is what centres the wheels. Shopping trollies are a good example of trail being used for self centering, thay have zero castor so when push in a direction the wheel will turn to the correct path (self centering) If you've had one that's had a knock, the trail is upset and the wheel wobbles from side to side trying to self center.
If you wish to increase castor you need to move the whole upper wishbone back or the lower one forward. Castor is what gives the car a steady feeling when driving along the road, greater caster angles serve to improve straight-line stability, they also cause an increase in steering effort.
Hopefully that makes things clearer.
Kind regards
John
__________________
Quality parts for the Haynes Roadster - manufactured to a standard, not down to a price.
|