negative camber negative caster

[Kern Dog]

My cars have equal numbers left and right. The roads here don’t have much crown and my cars dont pull to either side.

 

[1 Wild R/T]

My cars have equal numbers left and right. The roads here don’t have much crown and my cars dont pull to either side.

View attachment 1742235

With enough caster road crown doesn't matter..

 

[Kern Dog]

the service manual does say a 1/4 degree of less positive camber on the pass side

I haven't seen it mentioned whether the OP is using radial tires or not.
You have to understand that the specs for these cars were a product of their time and that things do change.
You don't have a completely stock engine anymore do you? Many people change the compression ratio, the camshaft specs, the piston ring gaps, adding electronic ignition, etc.
Do you run 110 octane fuel like what was available in 1970? I doubt it.
Alignment settings as specified were written for the masses. They had to account for the possibility of a skinny framed old lady or a burly Longshoreman. Bias ply tires didn't roll or steer as easy as radial tires do so the alignment settings had to aim for easier steering. Positive caster increases steering effort but greatly aids stability. The more caster you have, the more the car wants to maintain a straight line. Overcoming that takes increased effort. It is because of that that the FSM often called for greater caster numbers with cars equipped with power steering.
Still, even with manual steering with radial tires, you should be just fine with 2 degrees of caster unless you are physically compromised.

 

[gtxrt]

I haven't seen it mentioned whether the OP is using radial tires or not.
You have to understand that the specs for these cars were a product of their time and that things do change.
You don't have a completely stock engine anymore do you? Many people change the compression ratio, the camshaft specs, the piston ring gaps, adding electronic ignition, etc.
Do you run 110 octane fuel like what was available in 1970? I doubt it.
Alignment settings as specified were written for the masses. They had to account for the possibility of a skinny framed old lady or a burly Longshoreman. Bias ply tires didn't roll or steer as easy as radial tires do so the alignment settings had to aim for easier steering. Positive caster increases steering effort but greatly aids stability. The more caster you have, the more the car wants to maintain a straight line. Overcoming that takes increased effort. It is because of that that the FSM often called for greater caster numbers with cars equipped with power steering.
Still, even with manual steering with radial tires, you should be just fine with 2 degrees of caster unless you are physically compromised.

no not physically but mentally yes lol

 

[Kern Dog]

Some people just accept that these cars are old and that they are incapable of handling as well as new cars. That isn't accurate. These cars can handle quite well when the proper parts are used and the alignment settings deviate from what the service manuals called for.

 

[j-c-c-62]

The addiction for more castor may have downsides rarely discussed to help make informed choices.

In the October 2024 international issue of a very respected "Racecar Engineering" monthly touches on the subject. I assume the writer, Jos Claes, is more knowledgeable on the subject than myself as is everyone else contributing to the magazine. From page 5 briefly:

"The kinematic effect of any geometry, including castor angle, will result in a change in cross weights with turned steering. It helps to countersteer by holding back on some vertical load on the inner front wheel. This load would otherwise migrate to the outside of the wheels, and the effect is obviously reversed on the inner rear wheel. In other words, the limit of castor is traction capacity.

Some of us may remember the days when a weak chassis (with regards to torsional stiffness) proved faster on a wet track compared to more advanced cars that boosted far stiffer monocoques. The reason was that this weak chassis was easier to drive and, and more specifically, could drift in the rain compared to the better "dry" car. The kinematic effect of castor was much lower on torsionally weak chassis and made the four tyres operate under slower and more stable loads. Of course, such a car is significantly easier to drive, considering the endless spikes in steering wheel trace for the data of a car being driven in the wet."

In summation this is concerning the chassis lifting effects of significant castor when steering and its inherent redistribution of chassis weight when turning a castor aligned wheel. The writer uses the example of an unsuspended effectively rigid go kart to help visualize castors effects, mainly when at rest turning the wheel full lock will lift the outside tire, and why manual steering effort becomes so high when turning.

Almost everything has a downside. Pick your poison.

 

[gtxrt]

yes radial. if you look at the print out both sides are not equal. just want to move pass side a little. i was reading to just move the front adjustment out towards fender and that would give less - camber with out giving me more - caster.

 

[Kern Dog]

gtxrt, IF you move the cam adjusters the SAME amount equal but opposite directions will affect camber without changing caster.

Maybe I read this wrong but....
If you adjust the front cam IN and the rear cam OUT, you reduce caster. If you adjust the front cam OUT and the rear cam IN, you increase caster.
When you adjust both IN, you add negative camber. With both cams going OUT you add positive camber. Adjusting them in opposite directions does affect caster.

 

[Cranky]

I prefer stock ride height when possible. I think it's easier on parts and your butt.

I lowered my 66 and imo, it felt lots better. Didn't go nuts with it but it was down in the front by at least 1 1/2". The back lowered itself when the leaf springs went flat lol.

Some people just accept that these cars are old and that they are incapable of handling as well as new cars. That isn't accurate. These cars can handle quite well when the proper parts are used and the alignment settings deviate from what the service manuals called for.

When I started getting interested in handling I noticed that the late 70's cop cars had noticeable camber. You could actually see the camber! The first time to see it made me think the front end was worn but the cars were new and saw many more like that. In the late 80's early 90's my 66 exhibited the same thing and it handled great. Of course more caster was added which also help freeway speeds (and faster) tracking. Also, the more camber needed a tad more toe in....and tire wear was great. Don't have any specs since all of my alignments were done with levels, string and tape measures and some trial and error adjustments. Where's j-c-c lol.

 

[Kern Dog]

By the late 70s, radials were the overwhelming choice for OEMs. There were still some bias ply applications but engineers knew that radial tires allowed more freedom to add caster and negative camber to improve handling.
Even if you're not interested in fast and hard cornering, the changes I'm suggesting have numerous advantages. A well handling car is a far safer car. You'll be better able to steer out of danger, to avoid that deer or the dork that cuts in front of you.

 

[Darter6]

Kern, Good catch I was in a hurry and screw that one up !!!

 

[Cranky]

Maybe I read this wrong but....
If you adjust the front cam IN and the rear cam OUT, you reduce caster. If you adjust the front cam OUT and the rear cam IN, you increase caster.
When you adjust both IN, you add negative camber. With both cams going OUT you add positive camber. Adjusting them in opposite directions does affect caster.

Oh yeah, years ago a shop did an alignment on my vehicle.....and they went full circle with the adjuster cams. I guess you know what that did. Oh was I pissed!!! After that is when I took a real keen interest in doing my own.....there was one other that made me do it too but his mess up was minor.

 

[gtxrt]

one last question if I just want to adjust the front pass side adjuster do I need to loosen the back adjuster.

 

[Cranky]

one last question if I just want to adjust the front pass side adjuster do I need to loosen the back adjuster.

Probably wouldn't hurt but on the other hand, probably wouldn't bother anything if you didn't. It just depends on how much you plan on moving the front one.

 

[Kern Dog]

No. You can adjust one at a time.

 

[Cranky]

No. You can adjust one at a time.

I like to loosen the other if the adjustment on the other one is going to be big.....

 

[gtxrt]

I like to loosen the other if the adjustment on the other one is going to be big.....

just going to move less then 1*

 

[gtxrt]

here is where I am at. - 0.6 driver side and - 0.3 pass side caster where I want it. The toe in is a hair less than 1/8" where I want it. I need to add 1/2 of a degree of positive camber on the pass side. that 1/2* will change the toe to more toe out. any estimate how much toe out it will add ? but more important to get the toe back to 1/8" toe in do I just adjust the pass side adjustment or do I need to do both sides ?