I have no chassis lift due to caster?
Omitting all scrub, camber etc. effects, any caster at all will cause a height change in the nose when the wheels are cut. Exception: where the tire's tread profile radius is the same as its OD radius (a smooth arc centered on the axle).
If the tire is a narrow high-profile with a rounded section (Avon SpeedMaster), it will relax (sag) the nose with the wheel cut, and require effort to pull it back up from the sidewall to the tread crown to center the wheels. As the rake approaches 45°, the tire will lay over sideways at that angle at full lock - look at the old dragster pictures.
A low-profile, wide tire (275-40/17) will have the opposite effect, and must climb onto the sidewall with the wheel cut, but falls back easily to the flat tread when the wheel is centered.
Tony Foale has written about caster (rake) angle vs. trail stability at length, and appears convinced that caster can be negative (backward) as long as the trail is large enough, and if the chassis is sufficiently rigid the amount of trail required for stability is less than commonly recommended.
Any bike with telescopic suspension of course needs some rake simply to minimize the the wheel shock caused by striking bumps at speed, and the angle is proportionate to the vehicle speed - but for this different reason. Less angle causes wheel shock to vector into thrust against the sliders, etc., more angle causes reduced suspension travel at low to mid speeds, and potential bending force to the tubes.
