dont drop control arms do the same things as just shortening the springs?

[camshaftgsxr]

they just drop the spring pocket lower right? so isnt it the same as just cutting the springs as long as they are so short they bind?

[rwhit57]

Originally Posted by camshaftgsxr

they just drop the spring pocket lower right? so isnt it the same as just cutting the springs as long as they are so short they bind?

It's not exactly the same and I don't know what you mean about the binding part. When you cut the coils the geometry of the control arms changes more making it harder to align. With a drop pocket a-arm that change isn't as much. Look at it this way, by cutting the coil you bring the a-arm up to the crossmember, by moving the spring pocket you bring the crossmember down to the a-arm. Lowering spindles is the best route to lower the front because there is very little geometry change.

[J Knight]

x2. I used 3in drop control arms on my 95 Xcab, looked good but hated them. Lost alot of turning radius.

[SCOTI]

Originally Posted by rwhit57

It's not exactly the same and I don't know what you mean about the binding part. When you cut the coils the geometry of the control arms changes more making it harder to align. With a drop pocket a-arm that change isn't as much. Look at it this way, by cutting the coil you bring the a-arm up to the crossmember, by moving the spring pocket you bring the crossmember down to the a-arm. Lowering spindles is the best route to lower the front because there is very little geometry change.

Dropped lower a-arms are the exact same thing as cutting the coils or installing shorter coils on stock arms. The main difference is the spring rate doesn't change.

Consider the length of the spring as measured from the C/L of the a-arm pivot to the top of the coil. If the pocket is 'dropped', the longer coil sits further into the arm reducing the over-all height of the installed spring. The same thing happens w/a shorter coil in a stock lower arm (shorter over-all height from the point of pivot to the top of the installed spring). The 'shorter' installed spring has to move up farther before contacting the upper spring pocket when installed. The more it moves up, the closer the lower a-arm gets to the x-member, the more shims needed to align.

You still have to space the upper a-arms to compensate & correct the alignment. The more problematic issue is the lowest part of stock control arms are the bushings. With 'dropped' arms, it's now the 'dropped pocket' of the arms (even more stuff you have to worry about snagging the road).

[camshaftgsxr]

Originally Posted by SCOTI

Dropped lower a-arms are the exact same thing as cutting the coils or installing shorter coils on stock arms. The main difference is the spring rate doesn't change.


You still have to space the upper a-arms to compensate & correct the alignment. The more problematic issue is the lowest part of stock control arms are the bushings. With 'dropped' arms, it's now the 'dropped pocket' of the arms (even more stuff you have to worry about snagging the road).

thats what i always thought, i plan on 3 inch spindles and the rest on eibach springs, after they settle im going to cut them down to where i want it to sit then put longer bolts and spacers on the upper arms to compensate.

[SCOTI]

Originally Posted by camshaftgsxr

thats what i always thought, i plan on 3 inch spindles and the rest on eibach springs, after they settle im going to cut them down to where i want it to sit then put longer bolts and spacers on the upper arms to compensate.

With 3" spindles, you can do about 3" max on the spring drop before the lower a-arm bushings start bouncing off the road anywhere it's 'less than perfect'. You might not need to replace the studs either (I didn't have to on my old 74).

[rwhit57]

Originally Posted by SCOTI View Post
Dropped lower a-arms are the exact same thing as cutting the coils or installing shorter coils on stock arms. The main difference is the spring rate doesn't change.

It's the exact same thing, but different?
The results are the same, yes, but the ride characteristics and the geometry is not exactly the same. Very similar for sure, and Scoti you are right about the pocket being a road hazard, it puts that pocket very close to the ground.

[camshaftgsxr]

Originally Posted by SCOTI

With 3" spindles, you can do about 3" max on the spring drop before the lower a-arm bushings start bouncing off the road anywhere it's 'less than perfect'. You might not need to replace the studs either (I didn't have to on my old 74).

If this is the case how do you go about a 7"+ static drop in the front?
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[SCOTI]

Originally Posted by rwhit57

Originally Posted by SCOTI View Post
Dropped lower a-arms are the exact same thing as cutting the coils or installing shorter coils on stock arms. The main difference is the spring rate doesn't change.

It's the exact same thing, but different?The results are the same, yes, but the ride characteristics and the geometry is not exactly the same. Very similar for sure, and Scoti you are right about the pocket being a road hazard, it puts that pocket very close to the ground.

Ok, let me rephrase it....

Geometrically they are the same. The end result of 2" dropped arms & a stock spring or stock arms w/2" cut off the spring is the same dimension from the lower a-arm pivot point to the top of the spring.

The concept of "by cutting the coil you bring the a-arm up to the crossmember, by moving the spring pocket you bring the crossmember down to the a-arm" sounds good except for the physics (the x-member is fixed & doesn't move in relation to the frame; the lower arm is attached/pivots from the bottom of the x-member). When you lower the truck by either described method, the arm moves closer because it is pivoting off the fixed x-member & the over-all height of the installed spring has decreased.

When the arm moves upward (closer to the x-member) & swings through it's arc, the dimension from the pivot point of the LCA to the C/L of the ball-joint slightly increases vs. @ stock height which requires bringing the upper arm farther out to compensate.

Spindles wouldn't change the 'pivot-point to top of spring' dimensions.

[SCOTI]

Originally Posted by camshaftgsxr

If this is the case how do you go about a 7"+ static drop in the front?

You don't w/o a) driving very slow/cautious, or b) bottoming the a-arm bushings and/or x-member on the road. 5-6" is about the max w/o worry of damage. Even @ 5-6" of front drop, you still have to be alert of road conditions.

The 74 below has a little more than 5/7 drop. You can't roll a coke-can under the x-member which means the bushings are less than 3" from the road surface....

[camshaftgsxr]

One question I just thought about, how do you jack the truck up at that point? I can't believe I've never thought about this till now...
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[SCOTI]

Originally Posted by camshaftgsxr

One question I just thought about, how do you jack the truck up at that point? I can't believe I've never thought about this till now...

2 possibilities..... 1st is to use a very low profile floor jack. I have one that is very low & it still required removing the 'cup' to be able to wedge it under the chassis (notice I said wedge, not roll the jack under there ).

The 2nd (if you're not @ home & don't have the low profile jack handy) is to jack it from the front frame horn & slide a jack-stand under the LCA shaft. Once that is done, you can re-position the jack under the x-member.

[lilpoindexter]

On my lowered junk, I drive it ontop of a chunk of wood, a 2x6 or a2x4 or whatever. I also have a very low profile jack. I haven't had the misfortune of needing to jack my vehicles up on the side of the road...i guess I'd just call AAA.

[rwhit57]

My poor simplistic description of how the two methods differ has now been labeled a concept. Scoti are you an engineer? Is that your 74? It is one beautiful truck!! Here's my 5"/7" (close) drop on my 85. This is my 5th or 6th one and I did it all without knowing the crossmember is fixed. LOL

[SCOTI]

Originally Posted by rwhit57

My poor simplistic description of how the two methods differ has now been labeled a concept. Scoti are you an engineer? Is that your 74? It is one beautiful truck!! Here's my 5"/7" (close) drop on my 85. This is my 5th or 6th one and I did it all without knowing the crossmember is fixed. LOL

No need for the sarcasm....

con·cept   /ˈkɒnsɛpt/ Show Spelled[kon-sept] Show IPA
noun
1. a general notion or idea; conception.
2. an idea of something formed by mentally combining all its characteristics or particulars; a construct.
3. a directly conceived or intuited object of thought.

No, I'm not an engineer. I have discussed this very concept/idea w/an engineer specifically about the similarity of geometry.

That was my 74. It now belongs to another board member (Jonboy).

[N2TRUX]

Scoti is no enjunear, but he is the king of research. When he is interested in a topic, you will be hard pressed to find someone that digs deeper in to the physics of the workings.

Regarding the low profile jack, I have a pancake scissor that was OEM on the 88-98 Tahoe (Blazer). There are companies that sell pancake jacks that are about an inch thick when lowered.

[rwhit57]

No need for the sarcasm....
Scoti,
I can tell you do your research. Sometimes it's hard to explain things just typing them without having to write a book. You take the time to explain things and I respect that Randy

[Keith Seymore]

I also have done a quantity of 7 or 8 '73-87' pickups by cutting the coils, with no issues (one of which has over 190,000 miles as a daily driver).

Technically, it does change the spring rate, but from a practical standpoint you'd really have to have what we in the engineering community call a "calibrated a$$" in order to feel the difference...

[samuellg1977]

I have noticed that if you CUT THE SPRINGS, the front tires "lean in" a bit and it makes the truck look broken... Mine is that way. If you use the drop spindles, the tire remains straight and looks like you meant to lower it instead of "Damn, I broke it and now it's trying to fold up in the front". That is just my opinion and now, I am looking into drop spindles and yes, new springs to get the look I initially wanted, but, in my haste managed to booger up from the git-go!!

Sam

[SCOTI]

Originally Posted by samuellg1977

I have noticed that if you CUT THE SPRINGS, the front tires "lean in" a bit and it makes the truck look broken... Mine is that way. If you use the drop spindles, the tire remains straight and looks like you meant to lower it instead of "Damn, I broke it and now it's trying to fold up in the front". That is just my opinion and now, I am looking into drop spindles and yes, new springs to get the look I initially wanted, but, in my haste managed to booger up from the git-go!!

Sam

The tires leaning is the negative camber created as a result of the shorter spring. This is why the upper control arm gets spaced (shimmed) out to correct the 'lean'.

Cutting stock coils isn't a bad thing within reason. I've always figured about 20% increase in spring rate when cut but in reality it varies & would need to be checked on a scale for accurracy. I don't cut more than a coil.

[samuellg1977]

Originally Posted by SCOTI

The tires leaning is the negative camber created as a result of the shorter spring. This is why the upper control arm gets spaced (shimmed) out to correct the 'lean'.

Cutting stock coils isn't a bad thing within reason. I've always figured about 20% increase in spring rate when cut but in reality it varies & would need to be checked on a scale for accurracy. I don't cut more than a coil.

This is what I have done to my little banger... Notice the "lean" and then, a view of the spring (or well, lack thereof) from underneath. How do I fix (shim) this without replacing EVERYTHING? Thanks.

Sam

[Jonboy]

What does the shim stack look like at the upper control arm? If you need excessive shims (don't have enough length on the bolt to add enough shims) you can replace the upper cross shaft with an offset one so you can add more camber.

[SCOTI]

Originally Posted by Jonboy

What does the shim stack look like at the upper control arm? If you need excessive shims (don't have enough length on the bolt to add enough shims) you can replace the upper cross shaft with an offset one so you can add more camber.

That would be Moog p/n K6184 (Problem Solver Upper Control Arm Shaft).

[camshaftgsxr]

Originally Posted by samuellg1977

This is what I have done to my little banger... Notice the "lean" and then, a view of the spring (or well, lack thereof) from underneath. How do I fix (shim) this without replacing EVERYTHING? Thanks.

Sam

sports cars spend thousands trying to get that kind of camber

[bloodybigblock]

Originally Posted by rwhit57

My poor simplistic description of how the two methods differ has now been labeled a concept. Scoti are you an engineer? Is that your 74? It is one beautiful truck!! Here's my 5"/7" (close) drop on my 85. This is my 5th or 6th one and I did it all without knowing the crossmember is fixed. LOL

love that truck! thats all i gotta say!