I have a dual spring rate / lift height puzzle for you...

[Jim Oaks]

the first thing I got out of google led me right back here fwiw - everything comes back to TRS....

Ford Ranger - Designing Your Own Lift Brackets

www.therangerstation.com

That's so you don't get lost.

 

[ekrampitzjr]

With apologies to Willy Wonka...

Oompa Loompa doompadee doo
I have a dual spring rate / lift height puzzle for you

 

[Brain75]

If you are still up at 4:50 am I got to ask when the heck do you ever sleep?
Stresses just a little?

 

[Jim Oaks]

If you are still up at 4:50 am I got to ask when the heck do you ever sleep?
Stresses just a little?

Me?

I couldn't fall asleep Sunday night. I had a dentist appointment at 1130 am on Monday. Figured I would crash Monday evening. I didn't. I was probably awake for 43-45 hours. Didn't go to bed until about 6-7 am this morning. Woke up at 1pm. My sleep schedule is a mess.

 

[Brain75]

I forget timezones what shows as 4:49 for me is really 5:49 for TX/central zone.... still that is impressive/a bit scary I guess.
As an astronomer, my schedule is often screwed up pretty bad... 25 days a month I am with the "normies" and then we stay up till 4 or 5 am to do observation stuff and then the schedule is borked for 4 or 5 days after.
lifestyle leads to a bit of insomnia at times, randomly up at 2-3a and then just up for the day.

 

[4x4junkie]

So I was out for the holiday weekend, this thread's been busy lol

I'll try to respond to these one by one:

I guess you deleted your post about brainstorming coil springs for the newer Rangers... You should be happy to know (if you don't already) that many of these same principles can be applied to the new Ranger too.
Leverage ratio would be determined by the position the coilover is mounted to the lower control arm (LCA) between the bushings (pivot axis), and the lower ball joint (wheel), and can be used the same way in making a coil spring selection.
On a Tacoma I know the ratio is 1.9:1 and springs are ~550-700PPI (dependent on cab/engine/WB/trim configuration). The Ranger likely is very similar.

New Articles:

1983-1997 Ford Ranger Coil Spring Guide

Understanding Leverage On A Ford TTB Suspension

How To Calculate Motion Ratio For A Ford TTB Suspension

Mounting Early Bronco Coils To Your Dana 35 TTB

On your coil springs page, I think you might have the "spring will stand up" and "spring will fall over" descriptions backwards for Tangential and Square (the Tangential type is like what you would use on a coilover shock that has flat spring seats, Square requires a pocket or recess within the spring seat for the end of the coil to set into.

I'm curious about your info about the Supercabs having a 1" taller spring height than standard cabs... I've been under probably over a dozen of these trucks (Reg cab and Supercab) and have not noticed this (infact, it was the 4-cyl Reg Cab 4x4s that seemed to sit an inch higher than everything else). My buddy's '93 Supercab sat at the same height my '94 Reg Cab did when they were stock (both are 4.0L). Unfortunately I don't have a stock loaded coil measurement to provide since his is lifted now, but 10.5" is what mine was. With the geometry of the beams & brackets all being the same no matter the cab style, I cannot imagine how there could be any coil height difference between my buddy's truck and mine.



On the "Understanding Leverage" page, this part isn't correct:

Differential Placement: The differential is mounted on the passenger beam but positioned on the driver’s side. The driver’s side beam uses a slip-joint axle to allow for the independent movement of the beams.

The differential is mounted to the driver side beam. A slip-yoke & universal joint on the axle shaft allows delivery of torque to the (independently moving) passengerside wheel.

The further the spring is from the pivot point (in other words, the longer the distance between the radius arm attachment and the spring), the more leverage the axle beam can exert on the spring.

I'm not following this one (radius arm? or beam?)


Jim, I sincerely apologize, but as I get further & further down the page, I seem to be getting more & more lost. The part on Motion Ratio is particularly confusing (a wheel is part of the unsprung weight, or "unsprung mass". The "sprung mass" is the whole vehicle itself, minus axles, wheels, tires)... Another part says a longer lever (suspension beam) reduces (!?) the force applied to the spring (the opposite is true, so that whole section appears to be in error. Even when trying to use your numbers, I get final results that are different than what you have)... "Weight on the front axles and wheels: 200 lbs" seems to have a typo (and appears several times)... If that is the weight of front axle, tires, wheels that needs subtracted from total vehicle weight on front axle to come to Sprung weight, then it's a bit more than 200lbs... the axle alone probably weighs that.

Each of the pages also don't seem to account for the pivot axis being at a diagonal from the beam pivot to the RA bushing, and this is going to change every calculation on the page. Measuring only from the beam pivot (as you have it), the leverage factor will NOT come out to 1.43 for both the driver & passenger beams because the beams themselves are not the same length. However we do know that the pivot axes are symmetrical because the pivot axis is from the beam pivot to the radius arm bushing. Measured from the correct pivot axis, the leverage ratio will be the same for both sides.

I made up another diagram like the one I spoke of earlier:

Looking at it, you can see how both axes (Red) run from the pivot to RA bushing, and are at the same angle, the distance from the pivot axis to the wheel (Blue) is the same for both sides, and the distance from the pivot axis to the spring (Green) is the same for both sides. If this is not properly accounted for, people are going to end up with lopsided trucks, and they will wonder what they are doing wrong.


I know you have probably put a ton of time into these pages, but I'm just not sure how many will be able to follow them well (does anyone else have an opinion on this?)

 

[Jim Oaks]

My responses are in green.

@4x4junkie "So I was out for the holiday weekend, this thread's been busy lol. I'll try to respond to these one by one:"

I guess you deleted your post about brainstorming coil springs for the newer Rangers... You should be happy to know (if you don't already) that many of these same principles can be applied to the new Ranger too.
Leverage ratio would be determined by the position the coilover is mounted to the lower control arm (LCA) between the bushings (pivot axis), and the lower ball joint (wheel), and can be used the same way in making a coil spring selection.

On a Tacoma I know the ratio is 1.9:1 and springs are ~550-700PPI (dependent on cab/engine/WB/trim configuration). The Ranger likely is very similar.

I don't believe I removed anything and yes, I think we need to eventually add a page on coilovers.

On your coil springs page, I think you might have the "spring will stand up" and "spring will fall over" descriptions backwards for Tangential and Square (the Tangential type is like what you would use on a coilover shock that has flat spring seats, Square requires a pocket or recess within the spring seat for the end of the coil to set into.

That came from the Eaton Detroit springs website. Removed the stand up / fall over part of description.

I'm curious about your info about the Supercabs having a 1" taller spring height than standard cabs... I've been under probably over a dozen of these trucks (Reg cab and Supercab) and have not noticed this (infact, it was the 4-cyl Reg Cab 4x4s that seemed to sit an inch higher than everything else). My buddy's '93 Supercab sat at the same height my '94 Reg Cab did when they were stock (both are 4.0L). Unfortunately I don't have a stock loaded coil measurement to provide since his is lifted now, but 10.5" is what mine was. With the geometry of the beams & brackets all being the same no matter the cab style, I cannot imagine how there could be any coil height difference between my buddy's truck and mine.

No clue. I've read through so much crap that I picked it up somewhere. I thought it was the Moog site, but I just looked up springs for various applications and they're all listed at 10.50. So that's definitely wrong! And worse yet, I just remembered that when I measured my coil springs last year they were sitting at 14.50" and I was complaining that I only had a 4.50" lift. So, I apparently knew at one point they were originally 10.50. Somewhere I let myself get led astray. Fixed.

EDIT: I found it. This spring was listed for different 1996 Ford Ranger Super Cabs with a 11.50 Compressed Height:

Moog Coul Spring Set CC870Part Details

On the "Understanding Leverage" page, this part isn't correct:


The differential is mounted to the driver side beam. A slip-yoke & universal joint on the axle shaft allows delivery of torque to the (independently moving) passengerside wheel.



I'm not following this one (radius arm? or beam?)

Jim, I sincerely apologize, but as I get further & further down the page, I seem to be getting more & more lost. The part on Motion Ratio is particularly confusing (a wheel is part of the unsprung weight, or "unsprung mass". The "sprung mass" is the whole vehicle itself, minus axles, wheels, tires)... Another part says a longer lever (suspension beam) reduces (!?) the force applied to the spring (the opposite is true, so that whole section appears to be in error. Even when trying to use your numbers, I get final results that are different than what you have)... "Weight on the front axles and wheels: 200 lbs" seems to have a typo (and appears several times)... If that is the weight of front axle, tires, wheels that needs subtracted from total vehicle weight on front axle to come to Sprung weight, then it's a bit more than 200lbs... the axle alone probably weighs that.

It's my understanding that the sprung weight is everything above the springs. The unsprung weight is the wheels and axle. I've seen you tell people to weigh the front of the truck and then deduct 350 lbs to get the unsprung weight. I actually discussed this with another forum member who messaged me privately about this and we discussed this leverage issue. I've tried to understand it. Initially I thought the beam was pressing back against the bottom of the coil and that force was countering the down force being applied by the weight of the vehicle. We can't say it's changing the spring rate, because spring rate is determined by the physical properties of the spring and have nothing to do with weight.

I've seen you mention a 1.5 leverage caused by the TTB on different occasions but never explain what it is. I looked at a few websites for suspensions and they say that you measure from the beam pivot to the center of the wheel (43) and the beam pivot to the coil spring (43). 43/30 = 1.43. If you don't think that's correct, feel free to explain it. 1.43 is the leverage factor. 0.70 is the motion ratio. I'm pretty sure the math on the coil spring page is correct. I fed all of the information into ChatGPT, let it write it all out and pasted in the Leverage page. Its calculations matched mine, so I didn't really question it that much.

Each of the pages also don't seem to account for the pivot axis being at a diagonal from the beam pivot to the RA bushing, and this is going to change every calculation on the page. Measuring only from the beam pivot (as you have it), the leverage factor will NOT come out to 1.43 for both the driver & passenger beams because the beams themselves are not the same length. However we do know that the pivot axes are symmetrical because the pivot axis is from the beam pivot to the radius arm bushing. Measured from the correct pivot axis, the leverage ratio will be the same for both sides.


I made up another diagram like the one I spoke of earlier:
View attachment 123704

Looking at it, you can see how both axes (Red) run from the pivot to RA bushing, and are at the same angle, the distance from the pivot axis to the wheel (Blue) is the same for both sides, and the distance from the pivot axis to the spring (Green) is the same for both sides. If this is not properly accounted for, people are going to end up with lopsided trucks, and they will wonder what they are doing wrong.

Ok, this makes sense to me. Sometimes I can't understand it if I can't see it. So, is the Leverage the blue line divided by the green line?? Yes, it sucks that I put so much time into this and it's wrong. But I'd rather someone correct me and help me understand it then to be putting information out there that's not correct.


I know you have probably put a ton of time into these pages, but I'm just not sure how many will be able to follow them well (does anyone else have an opinion on this?)

Someone did and was kind enough to discuss it with me privately.
[/QUOTE]

 

[Curious Hound]

At the very minimum, this is off to a good start and just needs some refinement. @4x4junkie , thanks for that drawing. I never really thought about the relationship between the RA and axle beam affecting the pivoting motion and leverage. That's a great visual.

For what it's worth, you'll never catch me trusting chatgpt. Real human brains need to collaborate and figure this stuff out.

 

[SenorNoob]

Seeing that diagram: Is that why people usually report a smoother/softer ride with longer radius arms? It effectively lengthens the lever on the spring?

 

[lil_Blue_Ford]

Seeing that diagram: Is that why people usually report a smoother/softer ride with longer radius arms? It effectively lengthens the lever on the spring?

Good question, I’m curious at the answers here. I’ve been trying to follow this all but I’m not overly great at following the calculations here. I do know that both extended arm setups I’ve built for RBVs I extended to the transmission crossmember so that would definitely change the calculations and the angles.

On that thought, is there a way to calculate an ideal length for an extended arm? And does spring height and axle pivot height affect any of these calculations?

 

[4x4junkie]

I don't believe I removed anything and yes, I think we need to eventually add a page on coilovers.

My mistake, the post was further down than I remembered (post #56). Didn't have time to reply at the time because it was past 1:00AM.

That came from the Eaton Detroit springs website.

Interesting... Yeah the coil with the square end ain't gonna stand on it's end too well.

No clue. I've read through so much crap that I picked it up somewhere. I thought it was the Moog site, but I just looked up springs for various applications and they're all listed at 10.50. So that's definitely wrong! And worse yet, I just remembered that when I measured my coil springs last year they were sitting at 14.50" and I was complaining that I only had a 4.50" lift. So, I apparently knew at one point they were originally 10.50. Somewhere I let myself get led astray.

It happens... Time has a weird way of distorting memories sometimes (it's happened to me as well lol)

It's my understanding that the sprung weight is everything above the springs. The unsprung weight is the wheels and axle. I've seen you tell people to weigh the front of the truck and then deduct 350 lbs to get the unsprung weight. I actually discussed this with another forum member who messaged me privately about this and we discussed this leverage issue. I've tried to understand it. Initially I thought the beam was pressing back against the bottom of the coil and that force was countering the down force being applied by the weight of the vehicle. We can't say it's changing the spring rate, because spring rate is determined by the physical properties of the spring and have nothing to do with weight.

350lbs was an estimate of the axle (~200lbs) and ~75lbs for each wheel & (oversized) tire. With stock tires you'd probably subtract more around 300lbs.
I guess if you really wanted to drill down into the finer details, you could say that the 200lbs of axle unsprung weight is slightly offset because the motion ratio at the diff housing is less than at the wheel, but I never figured it to be significant enough to matter so I rarely included it to avoid further complicating things (its already hard enough trying to explain all of this without it being overwhelming lol). If I had to guess (without measuring everything out), it's probably in the neighborhood of a 40lb difference (unsprung weight slightly less, sprung weight slightly more).

I looked at a few websites for suspensions and they say that you measure from the beam pivot to the center of the wheel (43) and the beam pivot to the coil spring (43). 43/30 = 1.43.

And I think that's partly why this suspension has been so hard for many to figure out... There is a lot of incomplete and/or wrong info floating around out there because one person without the whole picture says one thing, then it's repeated to the next guy, and so on down the line until everyone is saying the same thing.
Simply measuring from the pivot works fine on an F-250 that has no radius arms, but when a RA is present (stock or extended), it changes things a bit.

Ok, this makes sense to me. Sometimes I can't understand it if I can't see it. So, is the Leverage the blue line divided by the green line?? Yes, it sucks that I put so much time into this and it's wrong. But I'd rather someone correct me and help me understand it then to be putting information out there that's not correct.

The difference in length between the Blue and Green lines creates the leverage ratio (LR), yes.
Unfortunately I don't have a truck with stock radius arms available to re-take these measurements, but I seem to recall the last time I did measure it, it was roughly 1.48:1, and so I just rounded up to 1.5:1 (extended RAs skew the LR very slightly lower... just guessing, maybe to around 1.46:1. I'll check mine next opportunity I have time). It should be noted that different offset wheels will also have small effects on LR as well (wider wheels with more negative offset will increase LR).

Someone did and was kind enough to discuss it with me privately.

Apologies. I will PM you from here forward.

For what it's worth, you'll never catch me trusting chatgpt. Real human brains need to collaborate and figure this stuff out.

A.I. will probably be our undoing.

 

[Jim Oaks]

As the saying from the 1980's: Garbage in = garbage out.

I had ChatGPT write (2) articles about me a couple of years ago just to see what it said, and in both of them I died around 2007.

I'm thinking that I can get ChatGPT to conclude anything based on what I tell it.

But this doesn't fix my problem.

I don't like it when someone tells me that I have to multiply or divide something by 1.5 and doesn't tell me why. Leverage doesn't explain diddly to me. Leverage is basically replying with 'because'.

I hated math in high school. I was really good at crash formulas though as a Technical Crash Investigator because I could see it. I understand what the numbers were and why I was calculating them the way that I was.

So, I'm still looking for a way to understand the TTB leverage so I can help others understand it and not just tell them 'because'.

 

[alwaysFlOoReD]

1.5 is a ratio. Put 1" of washers under the coil and get 1.5" of wheel movement downward... Or 1.5" of lift because the wheel can't move down into the ground!

 

[Curious Hound]

Or 1.5" of lift because the wheel can't move down into the ground!

That depends heavily on the type and condition of the ground.

 

[Jim Oaks]

Maybe it's closer to being correct now:

Understanding Leverage on A Ford TTB Suspension - The Ranger Station

@4x4junkie