A Couple Of Alignment Questions?

[horseballz]

Hi Folks,
Camber:
Needs to be set (0 degrees to -.50 degrees) and must be set first as it affects both the toe in and the caster. Most articles say there is no problem having a slight variation from driver side to passenger side to compensate for the crown in the road. Which side should be more negative for this purpose?

Toe In:
Most alignment specs list the toe in measurement in inches (1/16" to 1/8"). Is the measurement the difference between the front of the tires and the rear of the tires or is it 1/16" to 1/8" in from being straight? Either way, this spec seems kind of hard to get accurate, as measuring it in distance changes with the tire diameter as opposed to measuring it in degrees.


Caster:
Depending on which article you read, the recommendation is either negative 1.5 or 2.0 degrees to 3 degrees and up to negative 5 degrees for racing purposes. Is this a direct measurement of angle of the line from upper to lower ball joint (front to rear of car)to plumb/ vertical? Or is it the measurement of the difference of tire lean out/in with wheels turned 20 degrees to the left and then 20 degrees to the right? For example: most caster/camber gauges like this one:
http://www.speedwaymotors.com/Deco-Magnetic-Caster-Camber-Gauge,2698.html

as per their instructions, have you take the measurements by first turning the wheel out 20 degrees and the turning the wheel in 20 degrees with the difference being your caster measurement. I guess what I'm trying to understand is if you are actually measuring the spindle angle and/or if these types of gauges are simply calibrated/scaled to compensate for the fact that you are only turning the wheels in 20 and out 20 degrees? I understand that for negative caster, measuring the driver side, when you turn the wheel left, the top of the wheel will lean out and when turned to the right the top of the wheel will lean in. Is the spec of -3 degrees referring to the differnce in lean or to the actual spindle angle?

I realize this all sounds kind of confusing, but I'm hoping that someone here is an alignment expert who can understand my quandary/questions and help me out.
Thank You,
Gene

 

[69gmachine]

The outside tire needs to be more negative to compensate for the crown in the road, so for a left hand drive car, that is the passenger side tire.

The toe in is the difference between the front and rear of the tire. Make a mark in the center of the front tires. Rotate them so that the mark is somewhere between 4 inches off the ground and level with the center of the hub in front. Take your measurement, then rotate them to the back, again the same distance off the ground up to level with the hub. With a camber of 0 to -.5 degrees, the distance off the ground isn't super critical so long as you're consistent with where you take the measurement.

You absolutely do NOT want negative caster! It's like trying to push a shopping cart backwards. It will dart all over the road. Caster is a measurement of the angle through the upper and lower ball joints. The line needs to fall somewhere ahead of the center of the tire contact patch. The gauges that take a measurement from the outside face require turning the wheel in order to measure an angle that's 90 degrees to the gauge.

There is a limit to how much you can adjust caster using the strut rod as you will put the LCA bushing in a bind. It's better to move the top back. If you have adjustable UCAs, lengthen the front slightly (turn the rod end out about 2 turns more at the front than back). I've found 3.5 to 4 degrees is a good balance of centering effect and still being responsive to turn in.

For best results, you need to be in the car, or at least a sack of potatoes that weighs as much as you do, as your weight will affect the measurements. Also, you should go back and check camber after you've made the other adjustments and make sure it's still where you set it. If it moves, you need to find out why. Usually something is either worn or loose.

 

[horseballz]

Sorry Guys,
I wrote the caster spec wrong! It's supposed to be "positive". 69gmachine, I made a trammel setup that allows me to measure at spindle center, front and rear. Thanks for the info and the correction. DOH...
Thanks All,
Gene

 

[rbohm]

you want to set the caster first as it affect camber, not the other way around.

 

[grainboy]

I got stuck with negative 2.5 deg caster. Asked for 1-3 deg positive. Some shops do not know how to work on loder fords.

 

[horseballz]

Grainboy,
I would take it back and tell them to make it or your wallet right!
Gene

 

[PoppyMod]

Horse guy,
I,recently, went through all of this stuff. My ride is setup to be a curve carver, but, for street use. Therefore, after a total front end make over with TCP parts, including their manual rack, I opted for 2 degree + caster .-5 camber and 1/16 deg toe. Of course, I implied to the tech to compensate for road crown. It all works good in my case.
Keep in mind, the more positive caster the more manual effort required. I found, with my ride, 2 degree + is fine. It tracks well, it does not wonder, and the input for a manual R&R is a balance. This is my "realty" input.
As added, input, have those wheels "road" force balanced, to get an excellent true balance. Psst, put the lighter wheels on the front and offset each with their heavier alternative.
Doing this, should net you "0" vibrations from stop to , at least 90 mph.
Happy Motoring!

 

[grainboy]

I have granada spindles, and with my current setup, i suffer ffrom bumpsteer, ans it is squirelly at high speeds.

 

[PoppyMod]

I have granada spindles, and with my current setup, i suffer ffrom bumpsteer, ans it is squirelly at high speeds.

Hi,
Are you sure it's bump-steer? Bump-steer, usually, shows up as a "darting action" when hitting, bumps and divots in the road etc. The steering action tends to jump in some random direction. Then again, this may your definition of "squirrelly". i was able to mitigate some, if not most, of my bump-steer action, by insuring my outer tie rod arms are running parallel and on the same plane as the lower control arms. To do this, you may have to purchase a bump-steer kit.
Good Luck