Bought myself a cheap angle finder, now how do i use it??

"Pin Head" told me to put the angle finder on the flat machined part ontop of the knuckle. But that mean I have to take the whole hub,... apart, wich is a lot of work to just measure the caster angle.

I've taken off the steering arm (with a little help from other PBB'ers). If I then put the angle finder ontop of the flat spot between the studs will i then measure the caster correct?

When I measure my castor this way, the angle finder tells me it's 4 degrees to the left, is this good or bad?

I don't think anyone here will understand what i am saying, so i've attached some pics to make it more clear.

Chris

Measured caster: 4° to the left (front of my truck)

From what I can tell, that looks like the correct caster reading. More caster will point the pinion down toward the ground. I usually measure caster by removing the knuckle and putting a dowel rod between the upper and lower bearing cups. Then I measure the angle of inclination of the dowel.

Is the floor level, when measured parallel to the center line of the vehicle?

Are the hub centers the same distance from the ground, front to back on both sides?

Morgan

as long as everything is consistant front to rear (keep the front end the same height as the rear end. That amount of caster is probably perfect. It might be a bit much for manual steering and small tires but I have mine set at 4* and I really like it.

Harbor frieght come through for you???


:D

I measure caster slightly different.

Camber: how much the wheels point in towards each other at the top

Caster: The steering angle of the wheels (line drawn through upper and lower pivot bearings or ball joints).

Measure CAMBER (flat against the brake rotor). Now crank the wheels full left. Record the reading. Now crank the wheels full right. Record the reading. The difference is the CASTER angle.

Assumption is the wheels allow the same final angle from right to left.... I've seen some odd ball repairs were that wasn't so!

Typically I'll measure this will a plain old level and having two bumps on a metal tube. Think of a 1"x1" square tubing with two bolt heads sticking out of it the same distance. If the bolt heads are 15" apart, and hold straight against the rim you have zero camber.

Now to get the level straight you notice you need a 1/4" gap at the top of the bar. Using a little math, 1/4" & 15", or take the arcsin of .25/15" = just about 1 degree.

Tom :usa:

I just put a straight edge on the flat machined part of the knuckle that is exposed with the arm in place and then put the angle finder on top of that. You also have to have the wheels straight ahead and you need to measure the angle of the floor and subtract that from the measured knuckle angle. I would worry about having too much slop with the arm removed to get an accurate measurement.

You can measure caster by turning the wheel, but it is not straight froward. Many alignment machines (like the Hunter Laser Liner that I used to use) use this method, but they require calibration of the turn angle (this is built into the machine). W/O calibration, the caster would be the rotor angle measured with the wheel turned at 90 degrees, minus the rotor angle measured straight ahead (eg. the caster angle). The problem is that you cannot turn the wheel 90 degrees. You could measure it at 45 degrees and multiply that angle by 2 to come up with a reasonable estimate.

with the arm removed, all you have to do is slide the knuckle off, fairly simple actually (only thing is the outer c-clip, but that takes like 2 minutes.)