step cont arms or drop spindles....

[jmedero]

Ok lets open this up for discussion. Budget minded as we all are.... what is the better option? Welding in a step on the factory control arms or drop spindles? Truck is getting a 3' z or a raised and noctched x member. 22's. It will be bagged. Pros and cons of each...... ok go.

Nate I hope to get your expt opinion on this as well.

[Spray-Bomb]

Well drop spindles wont mess with your geometry at all, just lower the stance

raising the BJs will move your upper control arm up & start affecting the geometry some, not that that is a major problem, but it can be if you start moving it enough

So I vote drop spindles

[PBFAB.COM]

As Spray Bomb mentioned, one of the drawbacks to stepping the control arms is the effect it has on the suspension geometry.

I vote drop spindles too. I think you should be able to find some for a good deal these days.

[Twisted Minis]

Stepping your control arms doesn't actually affect the suspension geometry. Your geometry still see's all the pivots on the frame and spindle the same as they where before. I'm being technical though.

What it does do, is increase your camber gain, because you are moving your control arms up. While you still retain the same ride you had before, you are pushing the suspension farther up in it's travel.

That said, Spindles are always my first choice. Always. Especially if you want to lay on big wheels.

[XXL]

Originally Posted by Twisted Minis

Stepping your control arms doesn't actually affect the suspension geometry.

I disagree.

1) most people I've seen step control arms only do the bottoms. In this case, you're actually misaligning the pivot angles of the upper and lower arms. Definitely a geometry issue. 2) for those who step both the top and the bottom, while the 2 arms aren't misaligned with one another, they are on a different arc path than stock. Also a geometry issue. Will it work? Sure.

[PBFAB.COM]

Originally Posted by Twisted Minis

Stepping your control arms doesn't actually affect the suspension geometry.

Stepping the control arms DOES EFFECT your suspension geometry and kinematics... technically speaking.

At least we both agree on the solution!

[N2TRUX]

Spindles, for those that can't TIG. Which would be me..

[Shane]

<-- me too ... at least not like Twisted ... dude's an artist.

[jmedero]

Nice. Thanks for all the input. Always good to pick ones mind before you start cutting into your truck.

[Twisted Minis]

The way I see it, moving the pivot up on the control arm, is similar to just cutting the coil. The angle of the arm, in relation to the pivots (bushings and ball joints) still see the same imaginary line. The only difference when stepping the control arm is that part of the arm doesn't move, but your suspension will still see the same pivots, only in a different position. The same as cutting your coils, only with a different ride quality.

I will draw a diagram to explain this if I need to.

[PBFAB.COM]

Originally Posted by Twisted Minis

The way I see it, moving the pivot up on the control arm, is similar to just cutting the coil. The angle of the arm, in relation to the pivots (bushings and ball joints) still see the same imaginary line. The only difference when stepping the control arm is that part of the arm doesn't move, but your suspension will still see the same pivots, only in a different position. The same as cutting your coils, only with a different ride quality.

I will draw a diagram to explain this if I need to.

I think you were confusing my wording... The effects come from the changes in the bump (2") not the changes in the theoretical pivot points (as you have clearly stated two times). I never said it "changed" the factory geometry, just has negative "effects" on it and its kinematics due to the tighter arcs created by the compressed suspension. We have the same opinion, because it's fact... but to say it has no "effect" is false.

[Twisted Minis]

Okay I get what you are saying now. I agree it does effect your suspension. What XXL was saying about creating a geometry issue is more what caught my attention. But I believe that could be the same misreading again. But yes, as you said, the further the suspension is compressed, the further it is pushing it's intended design limits. So anything you can do to reduce that is good.

[Twisted Minis]

I think I am using the word geometry too critically, and also not thinking about the change in control arm angle effectively changing your front IC.

[jmedero]

See this is what I wanted. To hear the experts explain it. I am no expert in susp. That being said I have owned a bagged truck and have dropped many of my own vehicles.
Now I know the answer to this next one before I ask it. The answer is to get a Dropmember. But here we go.
3 inch z'ed or raise the xmember? I have seen many done but still am looking for opinions on what is the best and most effective solution. I like the raised xmember into the frame b/c you can then center wheel.

What do you think?

[vin63]

One of the more important issues to consider when you step the control arm to move up the ball joint location is that unless you compensate for or modify the steering arm, you do, in fact, change the geometry and introduce the potential for severe bump steer. With the ball joint at a higher location and the steering arm unchanged and at the higher location, the angle of the tie-rods increase, changing the angle or geometry.

[SCOTI]

Originally Posted by vin63

One of the more important issues to consider when you step the control arm to move up the ball joint location is that unless you compensate for or modify the steering arm, you do, in fact, change the geometry and introduce the potential for severe bump steer. With the ball joint at a higher location and the steering arm unchanged and at the higher location, the angle of the tie-rods increase, changing the angle or geometry.

That's assuming the location of the tie-rod to steering arm & subsequent geometry was ideal to begin with (having zero bumpsteer). GM has offered more than one vehicle w/less than optimal suspension design (G-body Malibu is one such veihicle that came from the OE w/bumpsteer issues).

So it's possible it can alter that relationship; making something less than ideal to begin with even worse.

[vin63]

Originally Posted by SCOTI

That's assuming the location of the tie-rod to steering arm & subsequent geometry was ideal to begin with (having zero bumpsteer). GM has offered more than one vehicle w/less than optimal suspension design (G-body Malibu is one such veihicle that came from the OE w/bumpsteer issues).

So it's possible it can alter that relationship; making something less than ideal to begin with even worse.

Most vehicles have some sort of bump steer condition because the steering arc is generally different than the control arm(s) arc - traveling in different radi (usually the control arms are shorter than the steering link). I'm just noting that if you increase the angle difference of the steering arm in relation to the lower control arm, a severe bump steer condition can be introduced and be potentially dangerous.

Originally Posted by Twisted Minis

See this is where I disagree. Like I said before, the pivots all still see the same line. You step the arm, it's the same as cutting a few coils.

It's very different than cutting coils - when you cut a coil, the tie end rod still travels in the same original plane in relation to the lower control arm. However, once you change the angle plane of the steering arm in relation to the angle plane of the lower control arm, you start to introduce the potential for severe bump steer. If the steering knuckle or arm on the spindle moves up by a ball joint spacer or stepped lower control arm without an equal spacer for the tie rod attachment, the angle of the tie rod changes in relation to the lower control arm angle. That's why a dropped spindle generally has a kick in steering arm (to keep the tie rod in the same location as the stock spindle) - that's to help maintain the original steering geometry. I'm just providing my 20+ years of experience in building hot rods and race cars. You are welcome to do what you want, I'm just trying to prevent you from having an ill handling vehicle, which are no fun and can be dangerous.

[N2TRUX]

Originally Posted by vin63

....I'm just trying to prevent you from having an ill handling vehicle, which are no fun and can be dangerous.

And we appreciate your input.

[SCOTI]

Originally Posted by vin63

That's why a dropped spindle generally has a kick in steering arm (to keep the tie rod in the same location as the stock spindle) - that's to help maintain the original steering geometry.

Actually, I thought the spindle 'spud' being raised in relation to the steering arm is what makes drop spindles desireable vs. raising the BJ locations (stepping the a-arm). The steering remains as the OE intended.

[Twisted Minis]

Originally Posted by vin63

One of the more important issues to consider when you step the control arm to move up the ball joint location is that unless you compensate for or modify the steering arm, you do, in fact, change the geometry and introduce the potential for severe bump steer. With the ball joint at a higher location and the steering arm unchanged and at the higher location, the angle of the tie-rods increase, changing the angle or geometry.

See this is where I disagree. Like I said before, the pivots all still see the same line. You step the arm, it's the same as cutting a few coils.

[gringoloco]

Originally Posted by jmedero

3 inch z'ed or raise the xmember? I have seen many done but still am looking for opinions on what is the best and most effective solution. I like the raised xmember into the frame b/c you can then center wheel.

The Z makes more sense to me for a few reasons: 1) You can get an easy 3" from the Z, more than 1.25" crossmember section and you run into major steering issues. 2) You can still center the wheels with a Z, just make your frame cuts at an angle.

Downside: lots of work, raised engine leading to a ton of problems, blah, blah, blah...

Originally Posted by jmedero

The answer is to get a Dropmember.

That's what I would do, hell, that's what I did. Twice.

[badblu97]

Originally Posted by gringoloco

The Z makes more sense to me for a few reasons: 1) You can get an easy 3" from the Z, more than 1.25" crossmember section and you run into major steering issues. 2) You can still center the wheels with a Z, just make your frame cuts at an angle.

Downside: lots of work, raised engine leading to a ton of problems, blah, blah, blah...

That's what I would do, hell, that's what I did. Twice.

Oh my god I just had one of those slap your forehead shoulda thought of that BEFORE I Z'd! ARGHHH!!!!

[Twisted Minis]

Okay ya the pivot isn't in the same spot, it's because I did not draw them correctly.

I guess I will not be able to convince you. Stepping the control arm DOES NOT change the spindle.

Here I modified the drawing to be correct as I intended originally.

[vin63]

Here's a better illustration with my front suspension at full drop. And, stepping a control arm or adding a ball joint spacer (old school) does move the spindle higher, which lowers the suspension - which is what you are trying to do, right? What you're not taking into account is that the steering arm is attached to the spindle. See below.

In this photo, the spindle is mounted directly onto the ball joint and the tie rod is located on a parallel plane about 4 inches above the lower control arm plane - both running slightly up hill in the photo since the air spring is deflated and resting on the bump stop.



In this photo, I removed the castle nut on the lower ball joint and moved the spindle and tire/wheel assembly up just 1.5 inches to simulate a ball joint spacer or stepped lower control arm (note the height difference of the bottom of the spindle). You'll see that the angle of the tie rod has changed significantly and is now running more up hill compared to the plane of the lower control to a point about 5.5 inches higher than the lower control arm.

In this second scenario, if the suspension traveled down, the tie rod would start to push out the steering arm (toe out) as the tie rod started to reach horizontal - the apex of the tie rod's arc of travel. This would cause bump steer (you can even see that in the bottom photo, the angle of the tire rod has pulled in the tire/wheel compared to the first photo). Imagine the increase in tie rod angle difference if the step was 1 inch higher for a 2.5 inch step.

[danno74]

Originally Posted by vin63

Here's a better illustration with my front suspension at full drop. And, stepping a control arm or adding a ball joint spacer (old school) does move the spindle higher, which lowers the suspension - which is what you are trying to do, right? What you're not taking into account is that the steering arm is attached to the spindle. See below.

In this photo, the spindle is mounted directly onto the ball joint and the tie rod is located on a parallel plane about 4 inches above the lower control arm plane - both running slightly up hill in the photo since the air spring is deflated and resting on the bump stop.



In this photo, I removed the castle nut on the lower ball joint and moved the spindle and tire/wheel assembly up just 1.5 inches to simulate a ball joint spacer or stepped lower control arm (note the height difference of the bottom of the spindle). You'll see that the angle of the tie rod has changed significantly and is now running more up hill compared to the plane of the lower control to a point about 5.5 inches higher than the lower control arm.

In this second scenario, if the suspension traveled down, the tie rod would start to push out the steering arm (toe out) as the tie rod started to reach horizontal - the apex of the tie rod's arc of travel. This would cause bump steer (you can even see that in the bottom photo, the angle of the tire rod has pulled in the tire/wheel compared to the first photo). Imagine the increase in tie rod angle difference if the step was 1 inch higher for a 2.5 inch step.

I think I see the problem here...The only reason the angle is so severe here is you are way to high up in the travel it doesn't matter where that lower control arm is at that point. As long as the control arm stays the same length and uses the same pivot points it is no different then a lowering spring. By using a ball joint spacer you actually change the pivot point that is why the tie rod spacer is needed.