Front axle geometry and "C" bushings.

[Oldtimer]

Need some help with my physics. If I add lift to my suspension, the effect is to raise the back end of the radius arms (frame goes up, wheels stay on ground). This would increase caster in front end alignment? So.... as the angle on the polyurethane "C" bushings increases (2°, 4°, etc) am I actually decreasing the caster angle to get it back to stock?:? ? Does this mean I should by a "C" bushing with a smaller number to increase caster in front end?:? ?:? ?

Maybe I should've asked this question with the morning coffee , not late at night when it hurts to think .

 

[76Broncofromhell]

Caster decreases as the arms travel downward, twisting the top of the axle forward. Look at it and you will see what I mean.

No, the numbers mean the increase over a stock bushing. If you install them incorrectly it can have the affect of turning you towards negative caster or zero caster as previously discussed in a different thread.

 

[Mikeg23]

Need some help with my physics. If I add lift to my suspension, the effect is to raise the back end of the radius arms (frame goes up, wheels stay on ground). This would increase caster in front end alignment? So.... as the angle on the polyurethane "C" bushings increases (2°, 4°, etc) am I actually decreasing the caster angle to get it back to stock?:? ? Does this mean I should by a "C" bushing with a smaller number to increase caster in front end?:? ?:? ?

Maybe I should've asked this question with the morning coffee , not late at night when it hurts to think .

As you lift your suspension you are decreasing the caster. As you raise the rear of your radius arm you are rotating the lower ball joint rearward and the upper ball forward. You put the aftermarket c-bushings in there to try and get the caster back up.

Think of caster like the front fork of a bicycle and it all becomes clear. If the front fork of your bicycle is strait up and down (zero degrees) it is hard to maintain a straight line. If you move the front wheel farther forward (positive caster) it handles better and if you move it too far forward it becomes harder to turn. Although that isn't as much of an issue with power steering.