Quote:
Originally Posted by hotrodA
But once moving, the tire's rotation has a gyroscopic effect and as downward force is put toward the ground, the weight being raised wants to return down, the snout returns to neutral, and the steering straightens out. Right or left turn is the same, given equal caster angle on both sides.
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hotrodA......I'm pretty familiar with the geometry and physics involved with MOST of what you say in your lengthy reply. I'm not understanding how gyroscopic effect of the rotating tire (as you describe it above) would have any tendency to "return a snout to neutral". Gyroscopic effect is the tendency for a spinning object to resist INITIAL movement, or change in plane...NOT to aid in returning to original position. In addition, your explanation about the spindle snout (on the INBOARD side of a turn, considering POSITIVE caster) angling more-downward toward the ground as the angle of the spindle rotation increases from straight ahead, does make some sense in that doing so, partial weight of the vehicle is being lifted. What you didn't mention is the fact that the spindle snout on the opposite spindle is angling in the opposite direction.....UPWARD, lowering part of the vehicle's weight. This action should
MOSTLY counteract the steering effort produced by the lifting of body weight on the opposite spindle. I say "mostly" because you would reasonably have to consider the Ackerman effect, in that the outboard spindle won't rotate on it's king pin to the degree that the inboard spindle does, hence......less gravity-assisted vertical movement of mass.
I guess that I'm really questioning why you thought it important enough to single-out the miniscule effect that positive CASTER would have on the effort needed to turn the steering wheel on a '34 Ford at rest, especially when the original poster clearly stated in his original post that putting slippery sheets under each front tire dramatically reduced the effort necessary to turn said steering wheel. Heck, ya can't even realistically adjust the caster on these things if you wanted to. It would make more sense to suspect low air pressure. Or, how about scrub radius? A positive value makes for more steering effort....at speed. But again, trying to read into the OP's post, he seems to be referring to slow speed and parking. I'm just surmising that sometimes, some of us may not think-through how the answer we give might REALISTICALLY apply to the information requested. DD