I guess I am dumb. I do not understand why you cannot read changes in caster with an angle finder as long as you use the ball joints as the reference point, and make sure the measurements are coming from the center of that reference point. Using that reference point would tell exactly how many degrees the axle has been rotated from the starting point. would it not?

 

Gotcha, so what are these castor measurements in the writeups mean, or are they just reference points that work?

 

No. Maybe a picture will help.

This is viewed from the front.



You see how the steering axis (balljoints in this case) is tilted in at the top? This built in angle is why you cannot just use an angle finder to make caster measurements. You must include this angle when measuring caster and the only way to do that is an alignment machine or the aforementioned caster gauge. Now, as I said before, if the steering axis was at verticle and the spindle (or knuckle in our case) was perpendicular to the steering axis, then yes an angle finder would be able to measure caster. That is simply not the case though. It might be on a go cart, but not on any vehicle that I know of.

 

They are merely a reference to make sure the setting is equal on each side. That's all that they can be.