Self centering

[robo]

Not quite the same thing because the trail wont become effictive untill you move where as the caster will be effiective at all times. Hence the lack of self centering when stationary. That castor like on a shopping trolley could be kicked arround 360 degrees and it will only straighten if you move forward. Also the inside wheel on turn in on the proper set up is forced downwards whereas the trail set up remains static. That in turn makes the steering feel vague, thats the reason all decent suspesion systems have caster built in. The mushrooms help but its only a patch up fix for an inherent problem, they do infact make the set up act as scrub which most would regard as undesirable.

Bob