Quote:
Too much caster can cause a violent shake after hitting a big bump at speed ie railroad tracks or potholes. 5 deg might work on a tabletop smooth track but I wouldn't want it on the street.
Kevin
Respectfully, I suggest that this symptom in a car has nothing to do with aggressive caster, and everything to do with the integrity and condition of the front suspension. For high caster numbers, I suggest one look up the factory alignment specs on a 1973 era Monte Carlo. That model exhibited none of the symptoms you attribute to positive caster.
When I was lobbying for the merits of positive caster, it was in the framework of the practical numbers one can get from a stock or near-stock Mopar front end, and in a car with power steering.
In addition to the lack of wandering and return-to-center benefits of positive caster, I also see it as a mechanism to obtain beneficial camber in turns. As I have said before, I am not in the camp of negative static camber fans (because I don't throw my pigs around corners quickly very often). However, positive caster will result in a shift toward negative camber on the outboard side and toward positive camber on the inboard side in a turn. This I find to be something desirable.
Down to just a blue car now.
| 
