Measuring Caster On A 3A

[cb750]

With the car on level ground and ride height set where I want it, am I correct in saying that if I follow a method in a previous post for a 2B it will work on my 3A? The method was to simply to measure the angle of the dummy strut in relation to the level ground using a digital angle finder. I was going to use a small vee block set on the exposed part of the dummy strut to give me a flat surface to put the angle finder on.

 

Rob

[Guest Tim Norman]

Its the angle of the wheel you want not the dummy strut.

[richyb66]

Its the angle of the wheel you want not the dummy strut.

 

Wouldn't that be camber? Rob's method seems ok for caster if he's measuring the angle that the dummy strut is inclined in side view.

[cb750]

Yes it's the angle looking in side view I was going to measure and I thought this would give me an accurate caster measurement without making a turntable and going through the 20 degree turning method. I will be using the face of the disc brake (they are new) and measuring the angle of that to give me the camber angle.

 

Rob

[Longboarder]

Your method would be fine if the dummy strut had a central pivot point for the top ball joint. But it's offset! So not accurate. As you are aware you Castor is the angle that an imaginary line, that runs through the centre of the top and bottom ball joints, makes with a vertical, viewed the perpendicular from the side of the car. This same line viewed from in front is the KPI. If the top ball joint is offset in the mushroom then the mushroom sides are no longer parallel to the castor or KPI lines. Same problem if the taper hole in the top of the mushroom is not aligned with the mushroom sides. OK its only 1 or 2 degrees but you are only measuring 5 degrees or so.

I would only rely on a dynamic measurement done with good kit and an experienced operator.

 

Nigel

[cb750]

Never thought of that Nigel, it looks like I'm back to making the turntable and doing it the normal way!

Rob