Is there such a thing as rear coil spring clocking for GMT900's?

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5StarCustmSolutns

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Feel like I read somewhere that both pigtails should be facing outward?

But cant remember if it was upppers or lowers or my imagination?

Anyone know anything about this?
 

Joseph Garcia

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From what I remember, both the coil spring base and top cup retainers have flat bottoms (no grooves in the cup retainers for the spring ends to fit into). As such, I do not believe that there is any directional positioning for the rear springs. Also, purchase new lower and upper rubber insulators, if you are going to change out the springs.
 
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mikez71

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I forgot which way my springs were facing!
But the rubber isolator on the bottom overhangs the perch on one side and deforms there, along with a spring end indentation.

Apparently, according to charm.li: "Important: Note the orientation of the spring as they are directional."

I wouldn't have thought it matters either considering the perchs are flat.
Looking at their (generic?) diagram, the spring end pigtail is located inboard on the upper side.
When the spring is being compressed up (and inwards) the upper outside edge load more, and maybe if the pigtail was on that side,
it might chew into the isolater/perch more easily? At least I can convince myself that's the reason!

 
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5StarCustmSolutns

5StarCustmSolutns

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When i had mine out i just took note of where the tags were positioned on the spring in relation to the body and put them back close-ish.
I don't think it really matters though.

That's what I felt like I did when I put these springs in about 14mos ago, but I went with the moog 80169, which is the z71 spring, and havent been a big fan of the ride ever since... Thought maybe I had them installed incorrectly....

ive learned a little about them since...
 
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5StarCustmSolutns

5StarCustmSolutns

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There's definitely a top and bottom to mine... I dont necessarily know which is which lol, but one direction they stand perfectly straight, the other has a couple degree lean to it...

Both of mine are right twist(clockwise), and what I had read(or possibly imagined?) was that the ends should both be facing outward, parallel to the axle......which isn't even possible with two right twist springs lol...

So I installed mine with both wire ends pointing towards the driverside...

I got a quote on some really impressive sounding custom springs last week from Custom Spring Specialties in Kansas. Long travel dual (or really more progressive) rate.. I'll ask the engineer Im working with over there tomorrow and follow up..
Spring clocking is a subject I hadnt even thought to ask about yet....
 
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5StarCustmSolutns

5StarCustmSolutns

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I wouldn't have thought it matters either considering the perchs are flat.
Looking at their (generic?) diagram, the spring end pigtail is located inboard on the upper side.
When the spring is being compressed up (and inwards) the upper outside edge load more, and maybe if the pigtail was on that side,
it might chew into the isolater/perch more easily? At least I can convince myself that's the reason!
googley AI says it matters but then the explanation of why falls flat on its face??


When mine are on smooth concrete floor and I gently rock them the least little bit towards the side of the wire end on bottom and apply very light pressure to the top with my fingetips i can most definitely feel the wire end of the bottom pigtail flex a mm or so before the "other half" of the pigtail loop makes contact with the surface...

when trying the opposite direction I have to lean them much farther just to get the wire end off the ground.. It definetly makes a difference
 

mikez71

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So I installed mine with both wire ends pointing towards the driverside...
I have a feeling this isn't right. I feel like your driverside? should rotate 180deg.
Sounds like your testing shows there's an inside and an outside to the springs, so they should be mirrored?

I'll take a look at mine and report back...
Welp, I got one spring upside down.. :think:flippin it tomorrow morning.
 
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5StarCustmSolutns

5StarCustmSolutns

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I have a feeling this isn't right. I feel like your driverside? should rotate 180deg.
Sounds like your testing shows there's an inside and an outside to the springs, so they should be mirrored?

I'll take a look at mine and report back...


Definitely plausible!

I was thinking of giving the most possible resistance to the rear, but I'm curious to hear how yours are.. I haven't tested yet and it'll be hard to notice anyway now as I customized the top mount bracket to recieve the stem of the top of a set of Bilstein 5100's I bought for $40 to drive to FLA and back with...

And when return will be figuing out how to fit 33" Bilstein 8125's under there as either coilovers or shocks to pair with the custom coil springs?? My Arnott's were DONE and I have already pulled compressor
 

mikez71

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Sticker on top of spring says 'FRAME'. Frame rails are outside of spring perch. Or are they implying 'chassis' like facing inwards? Another part number sticker lower down roughly same clocking. Oh well I have them facing out, where they would be easy to inspect the sticker, and facing the frame rails for these photos.

driver side spring, worn because it was upside down im sure. oops.
Photo should be correct direction. (?)
IMG_0401.jpeg



IMG_0402.jpeg


Passenger side
IMG_0403.jpeg
 
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5StarCustmSolutns

5StarCustmSolutns

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Sticker on top of spring says 'FRAME'. Frame rails are outside of spring perch. Or are they implying 'chassis' like facing inwards?

Hmmmm... My first thouhgt when I read that was: FRAME= top, considering the bottom is on axle...

But after seeing your pics I would say your 2 points with "the most" force (if there is such a thing) are out on each end at the widest point possible... That's one of the benefits of coilovers, wider= more controlled
I like that better than mine in the rear... Mine are assisting with axle wrap for gosh sakes lol...

I'll find out in the morning what Perry, the spring engineer, thinks...
 

89Suburban

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Sticker on top of spring says 'FRAME'. Frame rails are outside of spring perch. Or are they implying 'chassis' like facing inwards? Another part number sticker lower down roughly same clocking. Oh well I have them facing out, where they would be easy to inspect the sticker, and facing the frame rails for these photos.

driver side spring, worn because it was upside down im sure. oops.
Photo should be correct direction. (?)
View attachment 460459


View attachment 460458

Passenger side
View attachment 460457

Hmmmm... My first thouhgt when I read that was: FRAME= top, considering the bottom is on axle...

But after seeing your pics I would say your 2 points with "the most" force (if there is such a thing) are out on each end at the widest point possible... That's one of the benefits of coilovers, wider= more controlled
I like that better than mine in the rear... Mine are assisting with axle wrap for gosh sakes lol...

I'll find out in the morning what Perry, the spring engineer, thinks...

Yes frame means top. Pig tail orientation don't mean squat IMHO. Not unless the spring perch is molded with a "seat" for it.
 

mikez71

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Funny, I hadn't even thought about 'FRAME' meaning 'UP'!! (Why didn't they just say 'UP'??)
That is the most logical answer.. Guess that is the 'orientation'.

And, I would say who doesn't know which side is up?
Yet I had one upside down..

(I remember the spring falling out a couple times when I was installing..)
So I think it flipped on me and I didn't notice, and I didn't inspect afterwards..
because it looks wrong when they are upside down and the truck is sitting on them.

Regarding 5stars post about the spring feeling different, I guess it levels out with the truck sitting on it.
Top of spring has closer windings, so it's probably that end that feels uneven on the ground until the pigtail squishes down.
 
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Dustin Jackson

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My 2 cents here.. If the spring is symmetrically shaped it really doesn't matter. I've had my 81069 springs out of my Tahoe enough times (changing ride height with lift pucks) that I think I would have noticed something by now but they just seem to go in there any way that fits just fine. Both mounting surfaces have enough meat that the orientation of the pig tail shouldn't matter there will always be the same amount of contact.
 
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5StarCustmSolutns

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Yes frame means top. Pig tail orientation don't mean squat IMHO. Not unless the spring perch is molded with a "seat" for it.

This is exactly what Perry, engineer @ Custom Spring Specialties, just told me... (14hrs ago.. typed this and never hit send)

No such thing as clocking or orientation unless the insulator/seat has a negative imprint of the end of the spring molded into it...
 

89Suburban

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This is exactly what Perry, engineer @ Custom Spring Specialties, just told me... (14hrs ago.. typed this and never hit send)

No such thing as clocking or orientation unless the insulator/seat has a negative imprint of the end of the spring molded into it...

Yup, and a for instance, if we were talking about the front springs on the struts, they have orientation seating on the lower perch, it's molded for it.

Now on the rear springs, if you are re-using the old rubber isolators, you can rotate the pigtail to the part of the pad that is not squished to get more life out of it. But they are pretty affordable to replace with new.
 

Joseph Garcia

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Yup, and a for instance, if we were talking about the front springs on the struts, they have orientation seating on the lower perch, it's molded for it.

Now on the rear springs, if you are re-using the old rubber isolators, you can rotate the pigtail to the part of the pad that is not squished to get more life out of it. But they are pretty affordable to replace with new.
I agree. Replace the rubber insulators, as they are inexpensive, and rubber does deteriorate over time.
 
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5StarCustmSolutns

5StarCustmSolutns

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Yup, and a for instance, if we were talking about the front springs on the struts, they have orientation seating on the lower perch, it's molded for it.

Now on the rear springs, if you are re-using the old rubber isolators, you can rotate the pigtail to the part of the pad that is not squished to get more life out of it. But they are pretty affordable to replace with new.

Thank you (everyone) for the input/advice! Hopefully somebody someday will read and be grateful for my learning curve ;)

I did exactly this (the rotation) when I changed to the Z71 springs during the 14bolt rear axle swap in Sept '23...

So after deliberating wayyy too long (habitual routine...SMH), I decided to go dual rate coilovers... Ordered two 14" 400# and two 12" 350#, 3" id springs from Accutune yesterday... Hard to beat having the ability to adjust the the way to two springs work together through most of the travel range, along w/ ride height adjustment, the $125 lower price, and the ability to sell them to anyone vs only to owners of vehicles that use 5" i.d. coil springs....off-road/long travel 5" i.d. coilsprings on top of that; should've made that decision three weeks ago lol..
On the road, and this is for you @Joseph Garcia- (and thank you for greeting/welcoming every newb) because I think you have offered solid advice/feedback from your own experiences on just about every spring/suspension thread Ive ever seen on here. On the road, the Z55 is REALLY HARD TO BEAT! In Tow/Haul mode, the system is even more aggressive at countering pitch roll yaw dive squat etc.. IDK if it's good to run it that way all the time? But I have been for years. Corners flatter than any other full size truck/suv i've ever driven. And towing...load leveling....I need to find a picture real quick


20250316_135038.jpg


(FULLY aware how ill-advised I was in deciding to tow this, not advocating for it, just an example of how well Z55 works)

IMHO, towing and load leveling is where the Z55 shines the brightest.. Truck is not even running in this pic. It does have a very good weight dist hitch, but that's 11-11.5k behind it.. And it pulled this setup across @Geotrash 's fav route over the Appalachians, I-64.
Great OE system. Ahead of it's time, honestly......it's just not made for where I'm headed with this platform

20250712_073645.jpg


(last thing)
Back in Feb I spent a few days learing how Z55 works. The goal was to determine what size resistors I needed to make the BCM think the ride height sensors and OE shocks were still there and behaving as they should. Very soon (next couple weeks), I'll find out if I got it right or not?
Currently in the process of building a rear 4-link, and installing a different electronic shock control system :D.... IMHO, GM could've made a fortune selling a retro-fit kit like this...


One of the first things I asked SDI about was if they'd ever attempted to get GM's permisssion to tap into the Z55/Z95 sensor feedback system, because essentially, this is a Z55/Z95 system that you can fine tune and/or take full control of, on road or off... GM said no thanks. Ford, Honda, and Toyota however were in...
I bought this:


It was a little of an impulse buy for me (three days research) considering I needed 4 weeks to decide between custom coil springs and coilovers lol. But again the math and the tunability were the determining factors... To retro-fit the Fox Fact Race Series w/remote res front coilovers I have with Dual Speed Compression adjusters was gonna cost $848.. To buy the Bilsteins with the adjusters woud've been $1084 more than I paid for the two I bought without them... That $1932 is only $297 less than I paid for the E-Clik Universal System...

Cross fingers for me that I get this 4-link right and that my welds come out clean!

Next thread be either: Replacing Body Bushings or Rust Remediation or Frame Reinforcement? as I'm currently in the middle of all three ....smh :rolleyes:
 
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Joseph Garcia

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Thank you (everyone) for the input/advice! Hopefully somebody someday will read and be grateful for my learning curve ;)

I did exactly this (the rotation) when I changed to the Z71 springs during the 14bolt rear axle swap in Sept '23...

So after deliberating wayyy too long (habitual routine...SMH), I decided to go dual rate coilovers... Ordered two 14" 400# and two 12" 350#, 3" id springs from Accutune yesterday... Hard to beat having the ability to adjust the the way to two springs work together through most of the travel range, along w/ ride height adjustment, the $125 lower price, and the ability to sell them to anyone vs only to owners of vehicles that use 5" i.d. coil springs....off-road/long travel 5" i.d. coilsprings on top of that; should've made that decision three weeks ago lol..
On the road, and this is for you @Joseph Garcia- (and thank you for greeting/welcoming every newb) because I think you have offered solid advice/feedback from your own experiences on just about every spring/suspension thread Ive ever seen on here. On the road, the Z55 is REALLY HARD TO BEAT! In Tow/Haul mode, the system is even more aggressive at countering pitch roll yaw dive squat etc.. IDK if it's good to run it that way all the time? But I have been for years. Corners flatter than any other full size truck/suv i've ever driven. And towing...load leveling....I need to find a picture real quick


View attachment 462114

(FULLY aware how ill-advised I was in deciding to tow this, not advocating for it, just an example of how well Z55 works)

IMHO, towing and load leveling is where the Z55 shines the brightest.. Truck is not even running in this pic. It does have a very good weight dist hitch, but that's 11-11.5k behind it.. And it pulled this setup across @Geotrash 's fav route over the Appalachians, I-64.
Great OE system. Ahead of it's time, honestly......it's just not made for where I'm headed with this platform

View attachment 462115

(last thing)
Back in Feb I spent a few days learing how Z55 works. The goal was to determine what size resistors I needed to make the BCM think the ride height sensors and OE shocks were still there and behaving as they should. Very soon (next couple weeks), I'll find out if I got it right or not?
Currently in the process of building a rear 4-link, and installing a different electronic shock control system :D.... IMHO, GM could've made a fortune selling a retro-fit kit like this...


One of the first things I asked SDI about was if they'd ever attempted to get GM's permisssion to tap into the Z55/Z95 sensor feedback system, because essentially, this is a Z55/Z95 system that you can fine tune and/or take full control of, on road or off... GM said no thanks. Ford, Honda, and Toyota however were in...
I bought this:


It was a little of an impulse buy for me (three days research) considering I needed 4 weeks to decide between custom coil springs and coilovers lol. But again the math and the tunability were the determining factors... To retro-fit the Fox Fact Race Series w/remote res front coilovers I have with Dual Speed Compression adjusters was gonna cost $848.. To buy the Bilsteins with the adjusters woud've been $1084 more than I paid for the two I bought without them... That $1932 is only $297 less than I paid for the E-Clik Universal System...

Cross fingers for me that I get this 4-link right and that my welds come out clean!

Next thread be either: Replacing Body Bushings or Rust Remediation or Frame Reinforcement? as I'm currently in the middle of all three ....smh :rolleyes:
Thank you for your acknowledgement of helpful Forum members, and for the results of your extensive research. Very much appreciated.

Just another reason why this Forum ROCKS!
 

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