Caster/Camber question

[rumblecloud]

Is there a corresponding relationship between the amount of lift (or lowering) and the degree to which caster and camber are changed?

For instance, with a given tire size a 2-inch lift will result in a change XX-degree of camber and XX-degree of caster? Or is there more to it than that?

 

[Curious Hound]

Tire size doesn't matter. There should be a specific relationship between axle beam angle and camber. I've never seen a chart describing it. As the beam moves up or down, it pivots in 2 directions. One pivot is the axle beam pivot point. The other is from the radius arm mounting point on the frame. So it affects both camber and caster.

I'm at work. It's way more math than I want to tackle right now. Most of us just get new adjustment bushings with max adjustment range and make it work. I don't recommend much more than an inch or inch and a half of coil spacer lift. It's much better to use a lift kit that lowers those pivot points and lengthens the radius arms.

 

[RonD]

Depends on the lift method

Body lift doesn't change the chassis at all, so no changes in alignment
And you can get greater ground clearance by larger diameter tires that now fit, i.e. going from 29" tire to 33" tire gives you 2" more of ground clearance


If you change the angle of the front wheels hub then camber changes for sure, caster maybe
Suspension lifts can move the lower A arm down more(upper as well), which causes the hub/wheel to tilt in at the bottom, positive camber, when weight of vehicle is on the tires

i.e. if you jack up the front BY THE FRAME, the A arms drop down and that's the positive camber you would see if new suspension pushed the A arms down that far when weight was back on the front tires

There might be a general rule for angles if you look, but I don't know any off hand

Solid axle at the rear shouldn't change at all with either lift since its a solid axle

 

[rumblecloud]

Tire size doesn't matter. There should be a specific relationship between axle beam angle and camber. I've never seen a chart describing it. As the beam moves up or down, it pivots in 2 directions. One pivot is the axle beam pivot point. The other is from the radius arm mounting point on the frame. So it affects both camber and caster.

I'm at work. It's way more math than I want to tackle right now. Most of us just get new adjustment bushings with max adjustment range and make it work. I don't recommend much more than an inch or inch and a half of coil spacer lift. It's much better to use a lift kit that lowers those pivot points and lengthens the radius arms.

I really don't want you to math it out for me. I was just positing hoping that someone had already done all that. Like; "Oh yeah...there's a chart in the..."
I just did my uppers and lowers so that's why I'm asking-- just getting familiar with it all. My 1-1/2 inch washer lift is behind it all. I've gone thru the Tech Section and read 4x4Junkie's article. Bought the Moog adjustable bushing he likes and I am now just like "most of us."

......If you change the angle of the front wheels hub then camber changes for sure, caster maybe
Suspension lifts can move the lower A arm down more(upper as well), which causes the hub/wheel to tilt in at the bottom, positive camber, when weight of vehicle is on the tires....

That's exactly what prompted this post. Even though it was only a small lift, the camber is visibly changed.

Thanks for humouring me (see what I did there)

 

[RonD]

LOL

And remember you don't want stronger springs, that hold vehicle up higher, longer is OK, but same weight rating
Stronger(higher weight rating) lifts up the vehicle but you get a "shitty" stiff ride, oversprung
Its not a trade off, just bad design

Pickups are notorious for being oversprung in the rear to get their 1/2 ton or higher rating, higher weight rated springs are just the cheapest way to do it, so thats what you usually get from builder/manufacturer

You can use springs rated for empty bed weight with overloads added , costs more but way better ride

Also better for traction and control
When overspung wheel(s) hit a bump or dip the rebound pushes vehicles weight up and that LIFTS the lighter axles/wheels up so they have less traction or are off the ground completely, lol
Totally sucks when steering or trying to go uphill or downhill on a bumpy road, brakes only work when wheels are firmly on the ground

 

[Curious Hound]

"I really don't want you to math it out for me."

Sorry. I wasn't trying to make you feel guilty for asking. Just explaining why my answer didn't go into further detail.

It would actually be an interesting thing to work out some day.

 

[rumblecloud]

"I really don't want you to math it out for me."

Sorry. I wasn't trying to make you feel guilty for asking. Just explaining why my answer didn't go into further detail.

It would actually be an interesting thing to work out some day.

That was what I was wondering. It seems like it would be feasible - as you say, a ton of math involved -- not my strong suit.
thanks again have a good night.

 

[RonD]

With vehicle weight on the tires and wheels pointed straight
Measure the camber at wheels hub, or put a straight edge up and down on the rim only and measure its degree offset, should be close to 0

Then jack up THE FRAME 2"(lift height), and measure again, the degrees its changed will be the degrees you need to move upper A frame back or lower A frame out to get back same camber

Usually the camber adjustment bolts are on upper A frame and come in degrees of offset
2WD and 4WD can be different

They are usually listed with max. degree of offset, so 2deg, 3deg, 4deg, ect

So if you have a 3deg difference then get 4deg camber bushing/bolt, you can adjust a 4deg back to 3deg but can't adjust a 3deg past 3deg, so you want some wiggle room with this type of UNprecise measuring, lol

 

[bobbywalter]

The ttb is a cock sawker.

None of the basics strictly apply ...especially spring rates.

You have a double adjustable concentric if I remember right.

You can think of it as a circle within a circle. North south east west.

North being the forward or headlight side of the beam. And we will be on driver's side...

Let's say dead center is zero camber zero caster.

It's not ..but I digress

At that setting of zero/zero with it installed and truck resting on its weight and jounced out....

You measure say with an angle gauge.. and your actual measurement is cambered neg 1 degree...and have 1 deg caster....so top of tire is leaning toward engine and it won't want to return to center due to low caster....

You will want to line the concentrics up so the knuckle side of bushing hole is turned until they are west and south of dead center to get the top of the wheel to come out and add more caster at the same time ..

....you plot from there until you get the caster and camber you want... which I base on over center or under center of pivot line....


Now...when lifting ...with just the spring..

On a ttb....you actually generally do better with a slightly higher spring rate.


There is a high lever ratio with beams.


The damn thing moves in 3 arcs and toe can affect caster and camber depending on ride height relation to pivot axis.

Driving is different then resting...if you are over center.

You actually want to toe out with zero camber so it stays that way driving.

 

[rumblecloud]

Ya know...I think I kinda understand a lot of what you're saying...more later.