Front tire excessive wear

[Will N]

Originally Posted by Bob C

Caster max. 6 1/2º min. 3 1/2º Camber max. 2º min. 1/4º Camber plus side inclination max. 9º min. 8 1/4º Toe-in 3/32 Toe-out 15º turn 17, 20º turn 23 3/4 Tolerance 1/2º
These specs are for the Model A from the 1936 Ford Service Bulletins.

Thanks again Bob C. Can someone educate me on the meaning of camber plus side inclination? I thought that side inclination was the angle of the kingpin; an inward tilt toward the top so that a line drawn through the kingpin would hit the road where the center point of the tire hits the road. Camber is the tilt of the wheel/tire from vertical. Positive camber means the top of the tire leans outward. So is camber plus side inclination the angle between the line through the kingpin and a line through the tire/wheel? It seems to me that this is a function of the angle of the spindle on the steering knuckle, which I do not believe can be altered at all? Am I right?



I measured the caster and camber using a gauge I have, and I got 4 and 5 degrees caster, left vs. right. I got 1/2 and 0 degree camber left vs. right. Both caster measurements are within the specs, and the camber on the left side (which is the side that is wearing faster) is within specs, but the camber on the right is just a 1?4 degree out of spec.



I'm not sure I understand the specs for toe out on turn. I read it that at a 15 degree turn the toe out is 17, but 17 what? And at a 20 degree turn, it's 23 3/4, but again, what is the unit of measure? Is it inches, meaning the inside tire turns out 17 inches more than the outside tire turns in?

[Will N]

I think I'm answering my own question about toe out on turn here. Since the tolerance is given as 1/2 degree, I guess the unit of measure is degrees! So am I reading this correctly that when the outside wheel is turned 15 degrees, the inside wheel must turn 17 degrees? And when the outside wheel is turned 20 degrees, the inside wheel must turn 23 3/4 degrees? That should be easy enough to measure.

[Will N]

Ok, so I put the front tires on turntables with degrees marked off. These are my results
when I turn the right wheel in 15° the left turns out 17°- ok!
when I turn the right wheel in 20° the left turns out 23 1/2°- close to the 23 3/4 spec.
when I turn the left wheel in 15° the right turns out 17°- ok!
when I turn the left wheel in 20° the right turns out 19° BAD!


Is this telling me that the steering arm on the right side is maybe bent? It seems to me that with these results I should be seeing more wear on the right tire, not the left! If I turn the right wheel out to the 23 1/2° mark, the left wheel is showing 25° So when I'm turning right, the left wheel, which is the one that is wearing too quickly is turning in too much? I'm confused!



The turntables are free floating. I also noticed that when I turned to the left, both turntables stayed centered, but when I turned to the right, the left turntable moved forward from it's previously centered position. Is this telling me that the king pin inclination on the left is off so that it's not intersecting the ground at the center point of the tire?