I started this thread because Boberts thread was hijacked with this argument.
I say that caster effects camber only the slightest degree . and every one else says caster dose not effect camber at all . Hear is Boberts original thread
Please do not make any comments on Boberts thread about this issue Bobert made it clear he Is looking for something more than just a caster discussion on his thread so please Respect his wishes to change the subject
Boberts thread......www.mustangforums.com/forum/5-0-mustang/505498-front-suspension-need-input.html

Let the insanity begin

 

Caster does effect camber, but the degree to which it does so is dependent upon the amount of caster itself. More (+) caster will create more (-) camber out the outside wheel when turning the wheel, and the farther you turn the wheel the more the camber. Taken to the extreme think of a wheel with so much caster that the steering axis has been rotated a full 90 degrees. When you turn the wheel the tires won't move left or right, they'll just lean back and forth generating nothing but caster, and no steering angle.

 

no its doesnt.

caster is the front to back movement of the wheel as you look at it from the profile. even a worn out rear spring/shock can throw off your caster.


camber is the side to side movement of the top of the tire look at the tread side. this effects tire wear. and in no way is effected by caster or vice versa. they are two seperate adjustments


toe and heel is the adjust of the wheels in accordance to the steering wheel adjustment, this will effect the pull of the vehicle.



and ever since the mcpherson strut, caster camber is almost a thing of the past as far as modern cars go.

 

They are two separate adjustments and when sitting still changing caster will not change camber . It is not until you turn the wheel that camber shows changes . As a matter of fact I you want to know how much caster is built into any car you do so by taking two different camber measurements one with the tires at left lock and the second measurement at right lock and take the difference in the two camber readings is approximately the amount of caster the car has...

and for your camber caster comment . Boberts original post was about a fox 5.0 if I am not mistaken. Hear is a good article link specific to mustangs . one of the last paragraphs on the fist page of the article says that......

The basic Fox/SN-95 Mustang chassis was designed in the '70s. It was never intended to be a high-performance sports car chassis with an emphasis on good handling. The extreme alignment settings are essentially a Band-Aid for the car having too little camber gain during body roll, not enough Ackerman steering geometry, or positive caster,
The link http://www.mustang50magazine.com/tec...ent/index.html

 

Yes it does, look at your own picture. The caster angle is the angle of the steering axis, when the axis is (+) or the top of the steering axis is tilted towards the back of the vehicle, not only does the tire turn about the axis left and right, but it also tilts slightly from side to side. Like I said before, to see it, take it to the extreme where the steering axis is completely horizontal....all the tires would do when you turned the wheel is lean in and out, changing the camber. The more the (+) caster there is, the more the camber will be altered when the wheel is being turned(it's still only a tiny amount though).

Static caster and static camber adjustments are totally separate adjustments, yes. But caster angle can, ever so slightly, effect camber angle, but only when the wheel is being turned, not in a straight line. And the farther you turn it the more camber it generates. In reality most vehicles don't have enough (+) caster for this to be noticeable. It's more of a theoretical change in suspension alignment, since the actual change is usually so insignificant as to not matter, unless you have agressive suspension alignments.

Caster won't affect tire wear either, tow and static camber will though. And it's unlikely you could put enough (+) caster into any vehicle to cause it to affect tire wear during cornering.

 

I disagree a bit about it not being noticeable on tire wear If this theory is correct ( I call it a theory because I'm not sure about the actual numbers )
Theory - If you have 6 degrees of caster the difference in camber change from lock to lock should be approximately 6 degrees.
Straight is zero camber so a Quarter turn would be 1.5 degrees camber change because 4 Quarters at 1.5 = 6 degrees
(that said) a Quarter turn is still a sharp corner so you can figure that on a 1/8 wheel turn that is still .75 degrees positive camber change on the inside of the turn and a negative .75 camber change on the outside tire .

Tell me what you think
EDIT BY ME
this theory is wrong for more than one reson
#1 If this was correct the camber numbers would be divided by two.
#2 Even with divided by 2 (SAI) changes camber also( see later post )
#3 the camber gains are progressive (not divided evenly)

 

I found a more accurate way to measure your caster (but not prefect to the exact tenth of a degree . ) but is more accurate than just turning the front wheels from lock to lock as different cars have different angles to lock.
A more accurate method is to turn the wheels left from straight 14.5 degrees and measure the camber of the wheel. Repeat with the wheels turned right 14.5 from straight and take a camber reading. Take the total camber difference between the two measurements add multiply the difference by two.

This is an approximate caster reading .

 

Caster will affect camber when the wheels are turned.

 

Keep in mind that the chassis is rolling in such a manner as to reduce the camber on the outside wheel. -0.75° camber gain is not enough to cover for 4° of roll unless you've set -3.25° camber statically. On some computer I've got a caster-camber-steering angle spreadsheet that might be helpful.

Assuming that you can get precisely ±30° of steering at the front tires, then yes, the total camber change over the whole 60° would be 6°. But that's measured from one "lock" to the other, and I will tell you right now that it is not evenly divided about the straight ahead position. IOW, might be -4.5° on one side and +1.5° on the other. Or maybe it's the other way 'round, -1.5° and +4.5°; I haven't had to align any of my cars in a while so I don't remember which.

Not all cars can get the full 30° of steer, but there are a couple of formulas that provide the factor for converting camber range to caster for different amounts of steer. It's 2.0 for ±14.5° as mentioned, and the various aftermarket/circle track caster-camber gauges are set up for ±20° and a factor of approximately 1.5.

There's a Hunter Engineering (yes, the same folks who make the $$$$$ alignment racks for shops) paper that may shed more light on this whole business. Maybe even more light than you're ready for . . . anyway

Linky


Norm

 

(I tried to color coat )
oh for sure 0.75 would never to be enough to over come body roll .I was just making the point that as stock suspensions go their isn't very many adjustments that are available as a bolt on mod that can give you a variable camber change in the right direction on both the inside and out side tire during a turn .( without custom re engineering the whole front suspension )

Could you elaborate on this ? I assume you are talking about actual camber measurement during body roll. and when you say "not evenly divided about the straight ahead position." are you talking about during body roll or sitting still in the garage?

Can we take both of these measuring methods and come up with a Graph function or formula to give us an estimate of- (wheel turn degrees = % of camber change )
Something using these two or three formulas.
30 degrees =camber difference
20 degrees =1.5*camber difference
14.5 degrees =2*camber difference
and so on .I'll work on this

this is fun
thanks for the link (thats is a lot of light) and a lot of exact measurements and formulas that I am trying to simplify to very close approximations.To be useful for the average layman .I love exact numbers but if you data log all your approximations you can still put check marks next to what works and made a difference to complement your cars handling and driving style .If you use the same method and can repeat your results every time the simpler the better.

Off subject sort of (Ackerman steering geometry) is what I have been reading on here lately .love it