Flexy Coils and Mathematical Theory for Review

[Delancy]

Preface.

Attempting to either:

A. Lower the 80 by swapping all four corners coils.

B. Level the 80 by swapping the rear coils only.

At this point, mine sits at:

Front-25" COH (Center of Hub) to flare
Rear-26" COH to flare (COH/F)

These dimensions are higher than desired, assuming a 20" OE COH/F, by 1" front and 2" rear, considering a 4" level stance was the goal of mine and relayed to Flexy coil provider.

The current coils I have are:

PS rear 570mm
DS rear 585mm
PS front 590mm
DS front 605mm

Again, this resulted in:

Front-25" (635mm) COH/F
Rear-26" (660mm) COH/F

Therefore goal:

A. Would be:

Front- 24" (610mm) COH/F a reduction of 25mm RH

Rear- 24" (610mm) COH/F a reduction of 50mm RH

B. Would be:

Rear- 25" (635mm) COH/F a reduction of 25mm RH

All of this appears mundane, I realize, but based on the expense of correcting the

a.) all four coils lengths, or

b.) just the rear coil lengths, laying it out there because of a recent communication that has me baffled.

 

[Delancy]

After attempting to establish communication with coil producer unsuccessfully for a few weeks, a mate in Oz contacted on behalf and will be facilitating the transaction (Thanks, Barry.)

The reply to my original request that was similarly laid out as above was:

Quote-

"Hi Chris

The coils are on a 1:1 ratio meaning if we lower the free height 1mm then the ride height will lower by 1mm.

On a side note, you are going to change coils on the rear, I would suggest 15mm coil spacers and go 15mm lower in the free height. This is to reduce noises caused by the coil hitting the coil tower.

In Australia a stock Cruiser is about 530mm front and 540mm rear front centre of hub to flare.

Most people in Australia, when doing large lifts fit a part time kit so the front driveshaft only moves when you are going slow in low range and a little vibration isn’t a problem. Getting cross member spacers does help the front driveshaft a little bit but not great if you have a lot of vibrations, you may find this to be a handy tip if you don’t already know.

I noticed you are quite high on the drivers side. I suggest you swap over the rear coils, this will level you up.

Do not swap over front and rear."

-End Quote.

So, this would seem as simple as A.) Reducing the front coils free length (FL) by 25mm and reducing the rear coils FL by 50mm to achieve a 4" (100mm) COH/F measurement at all four corners

Netting following coils needed:

PS rear 520mm
DS rear 535mm
PS front 565mm
DS front 580mm

B.) Reducing the rear coils FL by 25mm

Netting following:

PS rear 545mm
DS rear 560mm
PS front 590mm unchanged
DS front 605mm unchanged

Questions coming on all, BUT

Option C:

Move rear coils to front, then order coinciding rear coils that'd level the stance based on, so:

PS rear "Xmm"
DS rear "Xmm+15mm"
PS front 570mm
DS front 585mm

Netting

PS rear y (COH/F)
DS rear y (COH/F)
PS front y (COH/F)
DS front y (COH/F)

 

[Delancy]

Concerns with suppliers statements

The original invoice from last year.




(Blurred out mate's address and info, for the record.)

Note the coils and arms listed at 4".

Wonder if that could be part of the issues I'm endured through, since they list 3", 4", 5" separately for the 80?





Superior Engineering

Email in the outbox shortly for rep.

Quote- "The coils are on a 1:1 ratio meaning if we lower the free height 1mm then the ride height will lower by 1mm." -End Quote

That seems odd.

Obviously, there's a constant rate of all coil lengths, but this may confirm the coil bind concern I had after cycling.

Pretty much, greater the lift, sooner the coils bind.

Quote- "On a side note, you are going to change coils on the rear, I would suggest 15mm coil spacers and go 15mm lower in the free height. This is to reduce noises caused by the coil hitting the coil tower. -End Quote

Counterproductive, in my opinion.

Why change the rear coil height to only add a spacer to compensate, if the coils are a 1:1 ratio? What am I missing?

Quote- "In Australia a stock Cruiser is about 530mm front and 540mm rear front centre of hub to flare." -End Quote

Then the original request of "4" lift" shouldn't have resulted in what I've got, unless the terminology "light weight" 80 doesn't bear the same implications here as OZ, since the COH/F dimensions seem the same to US 80s.

Quote- "Most people in Australia, when doing large lifts fit a part time kit so the front driveshaft only moves when you are going slow in low range and a little vibration isn’t a problem. Getting cross member spacers does help the front driveshaft a little bit but not great if you have a lot of vibrations, you may find this to be a handy tip if you don’t already know." -End Quote

Hahahahaha. (Not directed at him, but couldn't help but laugh).

The 20mm drive shaft spacer seen on Superiors site would still short the front shaft (based on what High Angle calculated the necessary shaft length) to be 30mm short.

Quote- "I noticed you are quite high on the drivers side. I suggest you swap over the rear coils, this will level you up. Do not swap over front and rear." -End Quote

I'm level from DS to PS, within a 1/4", depending on occupants and fuel volume.

When I installed the first time, based on a recommendation from supplier, I did have the rear coils swapped side for side, and a leaned horrendously.

Oddly enough, when I remeasured this morning in the rain, there was a 1/2" variance, where before its always maintained at 1/4" to none. Hmmm....

 

[Delancy]

Concerns with current shock order

Ordered shocks based on the fullest extension possible of the OE rear links and Superflex Radius arms, with the current coils installed.

Stupid?

Probably, but did take into consideration the rear lessening in RH by 1" (25mm) and ordered based on extension of rear links, sans sway, which does minimize extension by ~1 1/2". Therefore the concern of coils dislodging at full extension was squelched, since the currents DID NOT, even with sway removed.

Also, the shock travel dimensions did coincide with those suggested by a representative of Superior Engineering, based on 4" lift with Kings or Dobbins coil criteria, assumed 4" lift.

Now, very concerned that modifying all four corners, opposed to just the rear, may cause an issue with coils tapping.

Does anyone know the fullest extension of the OE rear links would be in a coil free length dimension?

Anyone know a similar dimension for the Superflex arms? :smiley:

Shocks ordered (paid for, built, and think shipped)

Rear 760mm (30") extended
450mm (17.75") compressed
290mm (12.25") shock travel
616mm (24.25") @ current RH

Front 768mm (30.23") extended
455mm (17.90") compressed
313mm (12.33") shock travel
635mm (25") @ current RH

To avoid having to cover each and every option I listed :smiley: , the biggest affect I could see in travel criteria will be up travel, since lowering RH will impact.

So,

Currently there's:

Front 180mm (7" ) up at RH
Rear 166mm (6.5") up at RH

A. If lowering all four corners to 4", will alter to:

Front 155mm (6" up) up at RH
Rear 116mm (4.5") up at RH

B. If lowering the rear 1" only

Front 155mm (6" up) up at
RH Rear 141mm (5.5") up at RH

C. Moving Current rears to front with new rears to level

Front xxmm (xx") up at
RH Rear xxmm (xx") up at RH

 

[Delancy]

Hoping this may help others that are considering this route, but I'm having difficulty trying to determine the best course of action.

Reason for is simply that.

 

[retrofive]

Reserved for my comment when I have more details

 

[NLXTACY]

Reserved for future pithy comment

 

[duggy]

I find it difficult to read your thread because of your comma usage

 

[retrofive]

FWIW I just walked out to measure mine again. Im running OME J coils on all 4 corners w/ 2" MT spacers up front, nothing in the rear. Im dead on 24" around the truck COH2F.

 

[Delancy]

I find it difficult to read your thread because of your comma usage

I'm sure proper spelling hinders readability, too.

I'm sorry you find it difficult to read.

If you'd be kind enough to grammatically correct my dissertation, I'll modify.

FWIW I just walked out to measure mine again. Im running OME J coils on all 4 corners w/ 2" MT spacers up front, nothing in the rear. Im dead on 24" around the truck COH2F.

So all J coils are the same free length and the spacer is to compensate for additional weight and correct rake?

I don't think I can space the front. Didn't want a 6" lift to begin with and that's what it'd wind up being if adding a 20-25 mm front spacer.

Maybe I ought to order short by inches and stack spacers, but (@ LT. ) partial reasoning for these coils was to eliminate spacers.

 

[Delancy]

Reserved for my comment when I have more details

Not enough details?

Reserved for future pithy comment

On the edge of my seat.

I realize my sanity is already at question.......

 

[scottryana]

Why bother with this when you are just going to do a custom 3/4 link

 

[Delancy]

Why bother with this when you are just going to do a custom 3/4 link

Because I'm conflicted on and all this crap will be absolutely worthless if I can't get it right.

At this point, whatever decision is made, I know the rear coils, that will lift 6" on a lightweight 80, won't be used on mine.

I've a buddy in OZ that will handle transaction and shipping to me, so this is what I'm thinking,

Figure out mine, whatever that is.

Figure out what two front coils will lift 6" to match the rears I won't be using and sell my rears (at a discount) order fronts for lucky Mudder to share in shipping costs for then to have 6" lift on Flexy's.

Later, when I decide what the crap I'm doing, can liquidate the coils, shocks, arms as a proven system or keep on this 80, and finish up with this suspension as final.

Start new project to link.

 

[TheBigBoy]

Chris, its clear you have absolute NFI what your doing lol

 

[Delancy]

Chris, its clear you have absolute NFI what your doing lol

Then offer up what you've got, Mark.

I never claimed to know what I'm doing, but knew what I wanted and relied upon the vendors I purchased from to achieve.

If you want to give me chit, feel free, I don't care and I deserve it, but I'm actually looking for a solution here.

 

[sleeoffroad]

I don't understand all the writing above. Slinky coils stay captive with long shocks, but at ride height, those dead coils are just spacers.

Take those fancy slinky springs, cut some winds of the top and be good. Grind the top flat as best you can so it seats proper. If the spring comes unseated, then capture the bottom so it can't fall out of the seat. The top cone will ensure it goes back where it should be.

To cut it, use a thin cut-off blade on a grinder. Start with enough winds to equate to 1/2" and then try, cut more if needed.

All I can tell you from wheeling the ShortBus is that it wheeled the best with 2.5" springs and 2" spacers that were captured top and bottom so that there was some negative spring rate when drooped out. All this striving for max droop is plain stupid on a 80. Looks impressive in most cases makes the truck way unstable.

Stop overthinking this. It is not a Ultra4 car. Never will be either. If you want it lower, then lower it and stop obsessing about droop. The only thing that is important is to make sure you don't over compress those Radflo shocks you don't have yet.

 

[TheBigBoy]

If you want to change the rear coils to have the same height at all 4 corners. Do that. All these measurements of coils your putting up dont mean a thing - they are flexi coils and GREAT coils. Your some how using them to get your shock measurements?

How to get correct shock lengths.
Install coils
Install tyres you want to run (size)
Add corrected weight you will be running
With no shocks installed, cross it up so all the weight is in the 2 appossing tyres. Adjust bumpstops so tyres are only just stopping any binding.
Adjust panhards for equal cycle either side (not as easy for the US)
Measure your compression length.
Using your shock size guide, find the correct compression sized shock (1" shorter)
Find the open length of that shock and using a ratchet strap close up the drop side tyre to the point the shock will restrict it at.
Then recheck everything. You may now be able to reduce the bumpstop size a little due to the new angle.

It's not hard

 

[Hoosier Daddy]

Not much help, but a couple comments on your correspondence with the Aussie fella. I think he was trying to say you should make your coil 15mm shorter than planned (ie, 65 mm shorter rather than 50 mm shorter) and then add the rubber spacer. Also, not sure how he figured you were sitting high on the driver's side, since all the COHTF numbers were front vs back, not left vs right. Maybe his statement was just mistakenly based on your coil lengths?

 

[Delancy]

That was a quick edit, Christo. Two in a row claiming stupidity is about all I can stand.

Trying to polish a turd, so I've little choice but to agree that it's stupid.

Purchase of arms was to free up the front. Based on research it would, but possibly a fail.

Purchase of coils was due to using similar on the rear of FJC. Possibly a fail on the 80.

 

[sleeoffroad]

Not much help, but a couple comments on your correspondence with the Aussie fella. I think he was trying to say you should make your coil 15mm shorter than planned (ie, 65 mm shorter rather than 50 mm shorter) and then add the rubber spacer.

Probably suggested that since 80 coils are ground flat on the top. If you cut coils, and not grind flat, then you create stress points where the tip of the coil meets the next wrap. So they want to put a rubber spacer in there to try and eliminate that, and also try to have the spring sit flat.