Other way around. Positive caster produces heavier steering and better self centering, negative caster makes for easier steering, but less self centering and stability. Most vehicles use positive caster, but there are a few exceptions, mostly '60s Ford products.
The KPI doesn't really have much to do with caster, it's related to camber, steering axis inclination, included angle, and scrub radius.
I stand corrected Bill,my understanding was negative caster meant the axle would be tilted
back towards the cab and positive was
forward to the radiator.
I was also led to believe the KPI was the kingpins relation to vertical on the fore and aft plane too.....
To use an old quote: If you believe all you hear,you'll eat all you see"
I guess I should've researched it myself.....
