step cont arms or drop spindles....

[jmedero]

So when what seems like 50 years ago.... I put a set of DJM drop arms on my s-10. It had a lower spring pocket, is that about the same thing as a stepped arm? Just wondering. It did ok till 2 mths later when I wanted to bagg the truck and could not use those arms.

[joe231]

Originally Posted by jmedero

So when what seems like 50 years ago.... I put a set of DJM drop arms on my s-10. It had a lower spring pocket, is that about the same thing as a stepped arm? Just wondering. It did ok till 2 mths later when I wanted to bagg the truck and could not use those arms.

exactly.......they had bags and s10's 50 years ago?

[jmedero]

yeah... dont you remember that?

[vin63]

Originally Posted by Twisted Minis

What you posted is spacing the spindle away from the ball joint. What I posted is spacing the ball joint away from the control arm. The ball joint and tie rod still retain the same amount of separation as they did before. I unfortunately do not have before/after pictures to show you, or pictures with the spindle on. I did not take any.

What I did does move the spindle up to lower the vehicle, in relation to the control arm itself. It pushed the ball joint up in relation to the arm, because the arm hit the frame. It lowered the car 1.5 inches, but the ball joint did not move in relation to the spindle or the tie rod. The ball joint still seats into the spindle, same as stock, and so does the tie rod, so their relationship is still un-changed. And the pivot points on the frame side where also not altered, leaving them the same. If none of these pivots where changed, then the steering geometry was not altered. The control arm is just taking a new shape to provide clearance for the frame.

I feel like I am repeating myself now. Lol. Hopefully we can get through this.

Yeah, I am, too. OK...for giggles, I machined a ball joint spacer last night from some scrap 6061 I had - I only had enough material to raise the ball joint 1". It is essentially making the ball joint pocket 1" taller. I pressed out the ball joint, pressed the ball joint into the spacer and then pressed the spacer (and ball joint) into the control arm, effectively accomplishing the same thing as a 1" step in the control arm or 1" higher ball joint location than original.

I put the lower control arm back to the same location and mounted the spindle and tightened it down - everything being in the same location as before. Now, as you can see since the spindle is located 1" higher on the lower control arm, the steering arm is also located higher - increasing the angle of the tie rod. So, I'm not sure how you guys are able to keep the angle of the tie rod from increasing. Let me know what is different that I did from what you are doing. Thanks.
...before

...after

[joe231]

i'm far from an expert, but this is how i see it....
very crude drawing in paint, it is not perfect so bear with me.


the green line goes through the lower control arm bushing and the ball joint, the red line is the tie-rod.....you can see that changing the shape of the lower arm does nothing to the relationship of the tie rod and lower ball joint, it is dictated buy the spindle, you would have to modify the spindle to change their relation......

[Twisted Minis]

Nothing is different. And I am not saying the angle of the tie rod will not change. It will obviously move up, because your ball joint also moved up. The control arm is the only thing that did not move. You basically lowered you vehicle by 1" by relocating the ball joint, and pushing the spindle and tie rod up the same amount.

What you did is basically what I illustrated in my drawing. Your geometry did not change, you just changed the shape of the control arm.

I don't want to sound rude, but if it doesn't click this time, I don't think I can make it click. I think I am going to have to throw in the white towel.

It seems like most of the others are on the same page though, and understand that a stepped control arm will not affect your geometry or tie rod/ball joint pivots?

[Twisted Minis]

Originally Posted by joe231

i'm far from an expert, but this is how i see it....
very crude drawing in paint, it is not perfect so bear with me.

Attachment 429925
the green line goes through the lower control arm bushing and the ball joint, the red line is the tie-rod.....you can see that changing the shape of the lower arm does nothing to the relationship of the tie rod and lower ball joint, it is dictated buy the spindle, you would have to modify the spindle to change their relation......

Thank you. That's basically the same thing I drew up before, but this is definitely more clear with the colors and all. I'm glad that most of use are on the same page.

[joe231]

Originally Posted by Twisted Minis

Thank you. That's basically the same thing I drew up before, but this is definitely more clear with the colors and all. I'm glad that most of use are on the same page.

yeah, your illustration explained it perfectly to me, different strokes.....

[Twisted Minis]

That drawing gave me another idea.

Rather than thinking that this moves the tie rod up, how about thinking that it is pushing the control arm down instead. Just the body of the control arm though, not the ball joint or tie rod itself. Just the metal form that holds your ball joint.

[vin63]

Originally Posted by Twisted Minis

Nothing is different. And I am not saying the angle of the tie rod will not change. It will obviously move up, because your ball joint also moved up. The control arm is the only thing that did not move. You basically lowered you vehicle by 1" by relocating the ball joint, and pushing the spindle and tie rod up the same amount.

What you did is basically what I illustrated in my drawing. Your geometry did not change, you just changed the shape of the control arm.

I don't want to sound rude, but if it doesn't click this time, I don't think I can make it click. I think I am going to have to throw in the white towel.

It seems like most of the others are on the same page though, and understand that a stepped control arm will not affect your geometry or tie rod/ball joint pivots?

Gotcha...that's my whole point is that making even small changes to the angle of the tie rod changes the steering geometry and introduces a bump steer condition. As you can see the tie rod angle changed significantly even with a one inch step - it pulled the wheel in quite a bit compared to the original location.

Originally Posted by Twisted Minis

Thank you. That's basically the same thing I drew up before, but this is definitely more clear with the colors and all. I'm glad that most of use are on the same page.

OK...I see, so from the drawing, what you're doing to compensate for the bump steer condition is to put a downward kick in the lower control arm, or use a taller spring. The only thing with that is the the downward kick in the control arm, or taller spring does not lower the vehicle.

[Twisted Minis]

Okay, yes you are putting a downward kick into the lower control arm. But you would not use a longer spring, because that would entirely defeat the purpose of modifying the control arm. By kicking the control arm down, and using the same spring your vehicle would be lower. All that drawing shows is how the control arm itself moves, but nothing else does. This is all exactly the same as the spring compressing an inch further.

[Twisted Minis]

I'm sorry, but I am going to throw in the white towel.

Does everyone else understand though? I want to make sure no one else is mixed up because of all this.

[vin63]

Originally Posted by Twisted Minis

That drawing gave me another idea.

Rather than thinking that this moves the tie rod up, how about thinking that it is pushing the control arm down instead. Just the body of the control arm though, not the ball joint or tie rod itself. Just the metal form that holds your ball joint.

Don't toss in the towel...post some photos of a real suspension supporting a vehicle that is on the ground to illustrate what you're talking about. I'm quite curious about this from a fabricator point of view.

The spring is what pushes the control arm up or down in relation to the chassis. The spring height in my photos remained constant as did the lower control arm location since the truck is sitting on the ground - this a real world scenario...I mean, I'm not making this up. This is not on paper or theoretical, this is a real suspension supporting the truck. I just don't want people to lose sight of the steering aspect when making suspension modifications. But, the angle of the tie rod increases in this example, which caused the toe in and eventual bump steer as the suspension travels down.

Now, if you are talking about increasing the height of the spring, or putting that downward kick in the lower control arm, then yes, the angle of the steering arm will not change, but the vehicle will not be lower. I've posted empirical data with the photos of a real suspension of a vehicle. I machined the spacer to simulate the step or ball joint re-location. I'm just asking for photographic proof on a working suspension - before and after - of what you are trying to explain since I'm obviously not understanding how in your explanation of a stepped lower control arm there is no change to the steering geometry or tie rod angle. If I'm wrong, I'm always the first to admit it. The thing is, I have raised ball joints and stepped lower control arms to lower vehicles, and in every instance I've had to add a spacer or bump steer adjuster to the tie rod mount at the steering arm to reduce the added angle.

[Twisted Minis]

Yes the tie rod angle moved up, just the same as if the lower control arm moved up with it. That is why your toe starts to change, because the angles are becoming more severe as if the vehicle was lower.

What you just said confirms this. Your spring height stayed the same, your control arm did not move, but your spindle moved up. Is you vehicle not lower now? The wheel is up higher, is it not? The spindle moved up, and so did the tie rod, all because the ball joint moved up.

Yes this is going to change your toe, just the same as shortening the spring the same amount would.

[Twisted Minis]

Originally Posted by vin63

Don't toss in the towel...post some photos of a real suspension supporting a vehicle that is on the ground to illustrate what you're talking about. I'm quite curious about this from a fabricator point of view.

I don't have any pictures really, because I never thought I would need them. I can take pictures of the arms on the Crown Vic when I get it back into the shop, but I do not have the stock control arms any more to swap and compare. So I can't provide you with the proof you seem to need.

I might have to pick this back up in a week or so, because I am getting frustrated. Maybe Nate can chime in with those illustrations he mentioned.

[vin63]

Originally Posted by Twisted Minis

I don't have any pictures really, because I never thought I would need them. I can take pictures of the arms on the Crown Vic when I get it back into the shop, but I do not have the stock control arms any more to swap and compare. So I can't provide you with the proof you seem to need.

I might have to pick this back up in a week or so, because I am getting frustrated. Maybe Nate can chime in with those illustrations he mentioned.

Sorry...I don't intend to frustrate you. I've put the before and after photos here in the thread. Just show me what you do differently in the photos I posted to not change the steering geometry - aside from adding a downward kick to the control arm, which doesn't lower the vehicle. It does create more space between upper and lower control arms and the frame - is that your goal in doing the step? The original post was asking about lowering the vehicle. In your Crown Vic example, it sounds like you fabricated new control arms...that's not quite the same since jemdero was inquiring about stepping the original arms. It's just that if I'm doing something wrong in setting up front suspensions, I want to know about it and/or get new ideas about safely lowering a vehicle. I appreciate your input.

[Twisted Minis]

I am just frustrated because the way I explain it makes sense to me, and it seems like to other people as well, but it's just not doing it for you. Not even close.

I built new arms for the Crown Vic, that raise the ball joint in relation to the arm. It's the same as stepping the control arm, only it's a different method. I would have stepped the stock control arm to achieve the same results, however the arm had a weird shape that conflicted with the frame at the height the customer wanted to go.

Adding a downward kick to the control arm is the same thing as stepping the ball joint up, it's just worded differently.

Honestly I don't know what to tell you at this point. I don't think I can help anymore. I've explained this every which way I can, two of us have provided drawings for you. I don't believe there is anything else I can do to help you understand this. Sorry.

[PBFAB.COM]

Vin-

This is one of those things that would be much easier to explain in person!

WE, meaning YOU, ME, and SETH (Twisted) all agree on the effects this modification would have.

This modification would effect the bumpsteer... but NOT because it's relation to the lower control arm. It changes because the suspension has essentially been compressed and now its static height would be 2" of bump from its original (unmodified) static height. As we all know, as the suspension goes into bump, the arcs become shorter and shorter thus creating exponential effects on the geometry.

As mentioned earlier, the effects of stepping the control arm is NO different than lowering the spring pocket, installing a 2" drop spring, or letting some air out of the bag.

Let me explain something that might make this come to light:

A suspension's geometry is based upon the pivot points of the components... not the physical shape of those components. So for right now, FORGET about the lower control arm and spindle... just visualize the pivots (control arm bushings, tie rod pivots, and ball joints).

1) Draw the pivot points in it's static height (don't connect the dots).

2) Now draw the pivot points of the suspension when it is compressed 2" (don't connect the dots).

3) Now draw the pivot points of the suspension when you have stepped the lower control arm 2" (don't connect the dots).

Your second and third drawing will look IDENTICAL. Bumpsteer will be equally prevelant in the second and third drawing, because it is the same thing!

[joe231]

Originally Posted by vin63

Sorry...I don't intend to frustrate you. I've put the before and after photos here in the thread. Just show me what you do differently in the photos I posted to not change the steering geometry - aside from adding a downward kick to the control arm, which doesn't lower the vehicle. It does create more space between upper and lower control arms and the frame - is that your goal in doing the step? The original post was asking about lowering the vehicle. In your Crown Vic example, it sounds like you fabricated new control arms...that's not quite the same since jemdero was inquiring about stepping the original arms. It's just that if I'm doing something wrong in setting up front suspensions, I want to know about it and/or get new ideas about safely lowering a vehicle. I appreciate your input.

i think Nate said it previously....
it doesn't change the geometry, it pushes the suspension to the outer limit of it's usable range.
the geometry is the relationships between the arm and tie rod, which does not change.
i think the confusion is possibly your use of the term "geometry"

Edit: guess Nate beat me to it

[vin63]

Originally Posted by joe231

i think Nate said it previously....
it doesn't change the geometry, it pushes the suspension to the outer limit of it's usable range.
the geometry is the relationships between the arm and tie rod, which does not change.
i think the confusion is possibly your use of the term "geometry"

Edit: guess Nate beat me to it

Unless the increased angle of the tie rod in the second photo is an optical illusion, the geometry did change. So, angles and the arces of travel are not geometry? Then, yes, my definition of geometry is different. The lower control is in the exact same spot because the truck is on the ground (air spring deflated and chassis resting on the bump stop in each photo for consistency to illustrate that I'm not altering the angle of the control arm). The only difference in my photos is that with the ball joint located higher, the tie rod angle increased up toward the steering arm of the spindle, which pulled the tire/wheel assembly in - that is bump steer that I'm trying to explain that occurs when you raise the ball joint location or step the sprung arm (lower arm in this case).

So, I guess my before and after photos do not show that the tie rod angle changed significantly from an alignment perspective? OK...I don't know how else to show that either, so I'll just have to agree to disagree that the tie rod/steering geometry changes when stepping the lower control arm or raising the ball joint.

[joe231]

deal...

[Shane]

Originally Posted by Twisted Minis

Does everyone else understand though? I want to make sure no one else is mixed up because of all this.

after 3 pages of responses I'd say other than you 3 no one else really wants to understand

[joe231]

more questions(just for my knowledge).....does suspension geometry change throughout suspension travel?
what is the definition of suspension geometry? is it the overall picture of the relations between individual parts and the arcs/movements they make throughout travel? how one effects the other?

[PBFAB.COM]

We ALL agree, and have agreed since the beginning of this thread, that the steering angle changes as the suspension goes through its travel.

Stepping the arm 2" achieves the same result as compressing the suspension 2" (regardless of what method... drop spring, bags, fat chick).

If you can't understand the rest by now, we will have to leave it for another time and place.

[Shane]

hee hee ... he said fat chick <beavis>