step cont arms or drop spindles....

[KB66]

Originally Posted by 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.

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.

Originally Posted by Twisted Minis

I still just don't get this. If the frame itself is unmodified, and so is the spindle, all of the pivot points are still identical. As long as your control arm isn't getting longer or shorter, then it won't change anything.

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

I've been reading through this and I don't think I follow...either the step changes the steering pivot or it doesn't. You mention that nothing changes when stepping the control arm, then you say the tie rod angle does move up. That's a change in the pivot point along the tie rod arc of travel. I think vin63s photos clearly show the increase in the tie rod angle - that's a significant change in that steering geometry.

Originally Posted by joe231

Attachment 429925

This illustraton shows two different control arms...the bottom image has the higher ball joint, but the arm itself is longer and has a downward angle that negates any height gained by the higher ball joint location.

[joe231]

Originally Posted by KB66

This illustraton shows two different control arms...the bottom image has the higher ball joint, but the arm itself is longer and has a downward angle that negates any height gained by the higher ball joint location.

[vin63]

Originally Posted by KB66

I've been reading through this and I don't think I follow...either the step changes the steering pivot or it doesn't. You mention that nothing changes when stepping the control arm, then you say the tie rod angle does move up. That's a change in the pivot point along the tie rod arc of travel. I think vin63s photos clearly show the increase in the tie rod angle - that's a significant change in that steering geometry.



This illustraton shows two different control arms...the bottom image has the higher ball joint, but the arm itself is longer and has a downward angle that negates any height gained by the higher ball joint location.

No need to bother...apparently I'm the only one who can see that the tie rod angle increases.

[Twisted Minis]

I am not ignoring the fact that the tie rod angle changes, all I was trying to prove was that the distance between the ball joint and the tie rod pivots are not changed on the spindle by modifying the control arm.

Either way, I've thrown in the towel.

[BuiltByBrooks]

Hello! Hey whats going on..........

[PBFAB.COM]

Originally Posted by vin63

No need to bother...apparently I'm the only one who can see that the tie rod angle increases.

The static tie rod angle does increase with a 2" stepped control arm.

The static tie rod angle does increase with a 2" drop spring.

The static tie-rod angle does NOT increase with a 2" drop spindle.

What are we arguing about?

[PBFAB.COM]

Originally Posted by Morbid Fabrication

Hello! Hey whats going on..........

Friday night... 7:45 and your on-line.... LOSER! Don't you have some sweet aluminum intake tubes to fill the gaps on?

[CG]

This stuff is way over my head, but doesnt really matter because thats why we have you experts to figure it out for us.

I have no idea if this will help (because Im lost lol) but here is a picture of a modified arm...probably too late =)

[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.

[joe231]

Originally Posted by vin63

No need to bother...apparently I'm the only one who can see that the tie rod angle increases.

that is not even the point trying to be made....the angle of the tie rod changes with dropped/cut springs also...not just with stepped arms....

Originally Posted by porterbuilt

The static tie rod angle does increase with a 2" stepped control arm.

The static tie rod angle does increase with a 2" drop spring.

The static tie-rod angle does NOT increase with a 2" drop spindle.

What are we arguing about?

[KB66]

Originally Posted by joe231

that is not even the point trying to be made....the angle of the tie rod changes with dropped/cut springs also...not just with stepped arms....

I think that is the point vin63 has been making. I'm not an expert, but doesn't bump steer occur when there is added tie rod angle, but the lower control arm angle stays the same? It appears to me that he showed the suspension resting on that bump stop in each photo so the spring and arm are at the same height, but the tie rod angle was still somewhat parallel to the lower control arm angle, when the ball joint height was increased the tie rod angle increased while the spring and lower control arms position did not change. So, that increased angle change would remain throughout the suspension travel creating more bumpsteer. If you just cut the spring, the tie rod and the lower control arm would still move up and down equally, right? There would be no added angle to the tie rod?

[vin63]

Originally Posted by porterbuilt

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

At least we both agree on the solution!

Originally Posted by porterbuilt

The static tie rod angle does increase with a 2" stepped control arm.

The static tie rod angle does increase with a 2" drop spring.

The static tie-rod angle does NOT increase with a 2" drop spindle.

What are we arguing about?

My orignal point was in support or your earlier post that stepping a control arm does change the geometry, particularly the steering and the potential for more bumpsteer than just a shorter spring - a shorter spring moves the entire suspension as a unit, not individual components like a higher ball joint that moves the tie rod up independent of the rest of the suspension being in the same position.

Originally Posted by joe231

that is not even the point trying to be made....the angle of the tie rod changes with dropped/cut springs also...not just with stepped arms....

Apparently, you do not not what point I've been trying to mak...my point has been that introducing an increased angle of the tie rod with the lower control arm in the same position creates more of a bumpsteer condition than just shortening the spring. It sounds like I should've posted photos of the before and after of the suspension at different locations along the travel with and without the ball joint spacer. Now, I have to press out that ball joint spacer.

[BuiltByBrooks]

Originally Posted by porterbuilt

Friday night... 7:45 and your on-line.... LOSER! Don't you have some sweet aluminum intake tubes to fill the gaps on?

Yea, Sorry Dad....It wont happen again.

[joe231]

Originally Posted by KB66

I think that is the point vin63 has been making. I'm not an expert, but doesn't bump steer occur when there is added tie rod angle, but the lower control arm angle stays the same? It appears to me that he showed the suspension resting on that bump stop in each photo so the spring and arm are at the same height, but the tie rod angle was still somewhat parallel to the lower control arm angle, when the ball joint height was increased the tie rod angle increased while the spring and lower control arms position did not change. So, that increased angle change would remain throughout the suspension travel creating more bumpsteer. If you just cut the spring, the tie rod and the lower control arm would still move up and down equally, right? There would be no added angle to the tie rod?

no one is arguing the tie rod angle changes, that happens with cut/lowered springs, stepped/lowering arms and anytime the suspension is compressed and rebounds. a stepped arm leaves the lower ball joint in the same place in relation to the tie-rod. basically all that changes is the spring pocket, which is the same lowering arms.......it has been stated and shown several times.
the shape of the arm doesn't change the straight line drawn through the ball joint and arm bushing.....

[joe231]

Originally Posted by vin63

My orignal point was in support or your earlier post that stepping a control arm does change the geometry, particularly the steering and the potential for more bumpsteer than just a shorter spring - a shorter spring moves the entire suspension as a unit, not individual components like a higher ball joint that moves the tie rod up independent of the rest of the suspension being in the same position.



Apparently, you do not not what point I've been trying to mak...my point has been that introducing an increased angle of the tie rod with the lower control arm in the same position creates more of a bumpsteer condition than just shortening the spring. It sounds like I should've posted photos of the before and after of the suspension at different locations along the travel with and without the ball joint spacer. Now, I have to press out that ball joint spacer.

a 2 inch drop spring, will do the same as a 2 inch lowering arm, will do the same as a 2 inch stepped arm, will do the same as compressing the spring 2 inches....in all those draw a straight line through the lower ball joint and the lower bushing, the relationship between that line and the tie rod will be the same in all of the above.....

[vin63]

Originally Posted by joe231

a 2 inch drop spring, will do the same as a 2 inch lowering arm, will do the same as a 2 inch stepped arm, will do the same as compressing the spring 2 inches....in all those draw a straight line through the lower ball joint and the lower bushing, the relationship between that line and the tie rod will be the same in all of the above.....

No it won't...but hey, to each his own. I can't do anymore than post before and after photos of an actual suspension in the same position. I've actually done these modifications to vehicles over the course of 20+ years of building and working on hot rods and race cars, and have had to align them afterward. So while the dropped spindle and shorter springs have mininal affect on the tie rod angle as a means of lowering a car, the stepped lower control arm/ball joint spacer has more affect on the tie rod angle and subsequently the steering, which was my original point. Why else would the old ball joint spacer kits have the corresponding bump steer adjusters for the tie rod joint at the steering arm? If everything was the same, as you point out, those kits would not have included those tie rod joint spacers.

[PBFAB.COM]

[QUOTE=vin63;3144220] a shorter spring moves the entire suspension as a unit, not individual components like a higher ball joint that moves the tie rod up independent of the rest of the suspension being in the same position.

Vin, I am sorry that we are unable to help you see the light on this one. I have been in similar situations in the past, where I was just unable to see, or make sense of what was being explained. I don't know what it is that is hindering us from clear communication. It's obvious we aren't on the same page with the explaination. I did not appreciate the fact that you insulted my intelligence or competence on an issue that I have more expertise, understanding, and knowledge than most... including you. I have done my best to not take offense or take it personally, and hope I have portrayed that.

Here's the last ditch effort to explain the point:


When I was referring to "geometry" not being changed by the stepped control arm, I was referring to the fact that:

The length of the lower control arm (this is the distance between the control arm bushing pivot's center-line, and the ball joint pivot's centerline) remains constant (when properly stepped).

The spindle's height (distance between the lower ball joint pivot's centerline and the upper ball joint's centerline) remains constant.

The upper control arm's length (distance between the control arm bushing pivot's centerline and the upper ball joint pivot's centerline) remain constant.

The outer tie-rod length (distance between the inner pivot's centerline, and outer pivot's centerline) remain constant.

If all these lengths remain constant, then there has been no "change" to the original geometry designed by GM. Sure, geometrical changes take effect due to the new location of the pivots...but they are located on the same points as if the suspension were experiencing 2" of bump.

The results or effects of stepping the control arm, are no different than when viewing the results or effects of a spring drop of equal distance.

As mentioned earlier, this is my final attempt to help clarify this point.

[Shane]

This is NOT in response to any particular post but this is getting a bit argumentative and could eventually turn into a pissing match guys.

Please proceed with caution.

Thanks.

[BuiltByBrooks]

YouTube - Inventor Studio Video/Rendering of RC...

[joe231]

Originally Posted by vin63

No it won't...but hey, to each his own. I can't do anymore than post before and after photos of an actual suspension in the same position. I've actually done these modifications to vehicles over the course of 20+ years of building and working on hot rods and race cars, and have had to align them afterward. So while the dropped spindle and shorter springs have mininal affect on the tie rod angle as a means of lowering a car, the stepped lower control arm/ball joint spacer has more affect on the tie rod angle and subsequently the steering, which was my original point. Why else would the old ball joint spacer kits have the corresponding bump steer adjusters for the tie rod joint at the steering arm? If everything was the same, as you point out, those kits would not have included those tie rod joint spacers.

i believe the key word is "KIT", you buy an (i presume) engineered kit they have made the necessary calculations too make a well behaved kit, ie taking bump-steer into account.....if you cut coils, or buy drop coils you are buying one component and it is up to you to make the required mods to complete your suspension, or get used to the dirrerence.....
i believe i have spent enough time on this and don't care to spend anymore, thanks

[vin63]

Originally Posted by porterbuilt

Vin, I am sorry that we are unable to help you see the light on this one. I have been in similar situations in the past, where I was just unable to see, or make sense of what was being explained. I don't know what it is that is hindering us from clear communication. It's obvious we aren't on the same page with the explaination. I did not appreciate the fact that you insulted my intelligence or competence on an issue that I have more expertise, understanding, and knowledge than most... including you. I have done my best to not take offense or take it personally, and hope I have portrayed that.

Here's the last ditch effort to explain the point:


When I was referring to "geometry" not being changed by the stepped control arm, I was referring to the fact that:

The length of the lower control arm (this is the distance between the control arm bushing pivot's center-line, and the ball joint pivot's centerline) remains constant (when properly stepped).

The spindle's height (distance between the lower ball joint pivot's centerline and the upper ball joint's centerline) remains constant.

The upper control arm's length (distance between the control arm bushing pivot's centerline and the upper ball joint pivot's centerline) remain constant.

The outer tie-rod length (distance between the inner pivot's centerline, and outer pivot's centerline) remain constant.

If all these lengths remain constant, then there has been no "change" to the original geometry designed by GM. Sure, geometrical changes take effect due to the new location of the pivots...but they are located on the same points as if the suspension were experiencing 2" of bump.

The results or effects of stepping the control arm, are no different than when viewing the results or effects of a spring drop of equal distance.

As mentioned earlier, this is my final attempt to help clarify this point.

My involvement in this thread was originally to support your earlier post #9 since it seemed like you were starting be singled out and challenged. I'm not sure where you think I insulted you...I was actually supporting your post #9 as clearly noted in my post #87. I was dissapointed that in a later post #32, you seemed to retract your position and attack me referencing an inaccurate drawing after I posted photos. So, there was no more insult or intent to insult from me, as I didn't take what you posted as a personal insult from you. As far as experience, I don't know you and you don't know me, which is why I never lay claim to knowing more than anyone else, but in my experience, those that do, are often the ones who feel most threatened - and I apologize if you feel that way, again that was not my intent. I just tried to post photos of a real suspension at full drop before and after a modification, so that others would consider steering as much as ride height in their modifications. My point was to show the increase in tie rod angle when locating the ball joint higher and how that affects the bump steer condition, and to encourage the others to post some photographic evidence of a real suspension before an dafter instead of hand drawings and conjecture. I have publicly stated before and continue to state that you guys make some of the trickest stuff in the market - no doubt.