Quote:
Originally Posted by Vintage Windmills
Even if he is noticing it sitting still? That would produce more of a rocking or tilting action. I'd guess more of an issue with the steering linkage running at an angle due to the lift. If thats the case, there'd be an up/down component to the force coming off the pitman arm if it doesn't drop enough to restore the steering bar to horizontal.
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Yes.
even if the drag link is at an angle there wont be much of a vertical force vector. it will be there for sure but not enough to physically move the truck that much. sitting still is the same as moving as far as scrub radius is concerned. scrub radius is the arc the center of the contact patch of the tire swings as the knuckle turns. the less backspace the more the scrub radius. that will magnify the movement of the wheel and tire vertically as the knuckle cycles from left to right. if there is to much positive caster(or negative, but there would be a lot worse symptoms if it was negative) the invisible point that represents the center of the contact patch at the axial center point of the wheel will move even more in the vertical plane. this is further amplified if you have a wider tire. my guess is the wheels are 10 inches wide and have a 4 or 4.5 backspace. that leaves the center point of the contact patch .5 or 1" further out from the face of the mounting flange. that is already a couple inches out from the pivot point of the knuckle. that would make the scrub radius probably 4-5" then with a 35 12.50 the outside of the tire is another 5 or so inches from the scrub radius. that just makes it more noticeable. in fact you probably barely notice it in motion because of all the body roll and weight shifting. sitting still is when it is the most noticeable.
if you have a chance bolt a set of tires and wheels from a '01-up chevy on it. i would be the noticeable height change is greatly reduced.
Ryan