Coilover Rates

Even with the rates, the info is still useless since we don't know preload, shaft at ride height, and spring lengths. On the surface (and just barely) though, unless you fat fingered a number, that is one rear heavy rig. That is about 2 x the combined rate of most rigs.
My rig is pretty heavy - it’s my biggest limiting issue. I carry a lot of tools and spares as well, probably too much. The welder is one thing, but the lathe and the mill are probably overkill…
@Nashville is the Hemi an iron block? Steel front fenders too?
Yup, iron block with AL heads - and that’s about the only AL on the rig - all the armor is steel.
 
  • Like
  • Haha
Reactions: hear and toximus
My rig is pretty heavy - it’s my biggest limiting issue. I carry a lot of tools and spares as well, probably too much. The welder is one thing, but the lathe and the mill are probably overkill…

Yup, iron block with AL heads - and that’s about the only AL on the rig - all the armor is steel.
Reminds me of Buck's rig. His rear sprung weight was the equivalent of taking a TJ rear scale weight and throwing the 35's, rims, and rear axle in the back plus some tools for good measure and setting that on the rear coil overs.

I told him to put it on a diet. He said okay and then unboxed the Genright 30 gallon fuel tank with skid to bolt under it. Yeah, this isn't what I had in mind. Later he showed me he was listening by moving the Hi-Lift from inside the back cargo area to the hood.

About the equivalent of tossing a couple of deck chairs off the Titanic to stop it from sinking.
 
You can take that to the bank too. It will work perfectly for you. Guaranteed or your money back.
I just started reading through your build thread. Looks like our Jeeps are almost identical (with the main exception of your being an LJ and mine a TJ). It was fun reading through the build and seeing the pics. I don’t have the patience to put all of my work down on paper/internet.
 
Fwiw, here is a good explanation on how coilover springs operate to the folks that don’t know. Straight from the source: Eibach Spring Tech.
“For many decades, the role of suspension springs in Motorsport had been overshadowed by the complex nature of the damper (shock absorber) when in fact, the entire suspension system is focused around the duty of the spring.”

Sure, that’s what I’d say if I sold springs.

It’s an interesting write up but it’s odd to me they say nothing about controlling the spring motion. Like absolutely nothing other than what I quoted.
 
  • Like
  • Haha
Reactions: toximus and jjvw
I just started reading through your build thread. Looks like our Jeeps are almost identical (with the main exception of your being an LJ and mine a TJ). It was fun reading through the build and seeing the pics. I don’t have the patience to put all of my work down on paper/internet.
Did you do Jk Rubi axles?
 
They manufacture and sell springs. That’s what they are explaining. Take it for what it is: an explanation of how dual rate springs work. Personally, I thought it was we written and did a great job a
Did you do Jk Rubi axles?
I have a Rubicon TJ front axle with 5.13’s, ARB, Yukon shafts, tera knuckles, etc. Rear is a Teraflax CRD60.
 
I ordered rear coilovers from accutune, told them about my Jeep and they sent 150/100 coils. My rig is light and they decided it would be pretty close to factory weight. No spare or seat and a soft top, but add aluminum armor and the weight of brackets, gussets, cross-member etc. That puts the spring rate right at 125, until the first coil locks out, then it's 150. I don't pretend to be part of the few that knows how to properly set up coil overs. But I'm learning from hands on experience.
Like you said. We'll see
 
I ordered rear coilovers from accutune, told them about my Jeep and they sent 150/100 coils. My rig is light and they decided it would be pretty close to factory weight. No spare or seat and a soft top, but add aluminum armor and the weight of brackets, gussets, cross-member etc. That puts the spring rate right at 125, until the first coil locks out, then it's 150. I don't pretend to be part of the few that knows how to properly set up coil overs. But I'm learning from hands on experience.
Like you said. We'll see
I think someone told you the combined rate incorrectly. I did the math and came up with 60 lbs per inch combined rate and to check my math, I found a dual spring rate calculator and it shows the same rate.

1642645919596.png

If you aren't driving it, when you do, just for the fuck of it, move the stop nuts down to about 2" above the heavier 150 spring and go drive it. You won't be able to tell when the rate changes from 60 to 150 even though that is almost 100 lbs higher. Also another way you can tell that springs don't fucking matter.
 
I think someone told you the combined rate incorrectly. I did the math and came up with 60 lbs per inch combined rate and to check my math, I found a dual spring rate calculator and it shows the same rate.

View attachment 303838
If you aren't driving it, when you do, just for the fuck of it, move the stop nuts down to about 2" above the heavier 150 spring and go drive it. You won't be able to tell when the rate changes from 60 to 150 even though that is almost 100 lbs higher. Also another way you can tell that springs don't fucking matter.
It does indeed look like I'm mistaken. For some reason I remembered add the two rates and divide by 2. Guess I fabricated up that memory. Thanks for the correction. Like I said, I won't pretend to know I'm one of the ones that knows what they're doing.

I'm curious about this whole spring thing rate thing, and I'm looking forward to running the experiment myself, even if I know the outcome. I'm one of the guys who did take the time to remove my shocks altogether and drive around. I will report back when I get there.
 
It does indeed look like I'm mistaken. For some reason I remembered add the two rates and divide by 2. Guess I fabricated up that memory. Thanks for the correction. I'm curious about this whole spring thing rate thing. I'm looking forward to running the experiment myself, even if I know the outcome. I'm one of the guys who did take the time to remove my shocks altogether and drive around. I will report back when I get there.
The easy way to remember it is product over the sum. Add the two rates together and divide that into them multiplied together.

What is very eye opening is a very heavy rig will only run up to about 80-85 lb. combined rate.
 
The easy way to remember it is product over the sum. Add the two rates together and divide that into them multiplied together.

What is very eye opening is a very heavy rig will only run up to about 80-85 lb. combined rate.
Good, that (hopefully) means my light weight rig might be in the ballpark at 60
 
Good, that (hopefully) means my light weight rig might be in the ballpark at 60
The other thing that is important is how springs work. If they worked the way most think they do, then it wouldn't be out of the question to run a long 60 or 70 lb spring on top of a very high rate shorter spring like 5-600 lb per inch on the bottom and set the stop nuts so the lower spring hits at a couple of inches or so of shaft left to help slow down the shock from bottoming out. None of my shock tuners will set it up that way since the pair of springs should be within a fairly narrow range of each other. None of them will ever try to make the springs do the work the shock is supposed to do.
 
Its easy to understand peoples spring misconception. Physics often doesn't work the way we think it should. It took me forever to finally grasp this simple concept:

If two cars, both traveling at 60 mph hit each other head on, the resulting force is not equal to one car hitting an immovable wall at 120 mph. Its still just 60 mph. I knew this to be true, but it was difficult to grasp the why.

I'll eventually wrap my head around it.
 
Its easy to understand peoples spring misconception. Physics often doesn't work the way we think it should. It took me forever to finally grasp this simple concept:

If two cars, both traveling at 60 mph hit each other head on, the resulting force is not equal to one car hitting an immovable wall at 120 mph. Its still just 60 mph. I knew this to be true, but it was difficult to grasp the why.

I'll eventually wrap my head around it.
Or how a snatch block works when tied back to the rig the winch is on. If the pulling force from the winch is 1000 lbs, then each line has 1000 lbs of force on it and that doubles the winch pulling force. (assuming no frictional losses)
 
  • Like
Reactions: psrivats
Or how a snatch block works when tied back to the rig the winch is on. If the pulling force from the winch is 1000 lbs, then each line has 1000 lbs of force on it and that doubles the winch pulling force. (assuming no frictional losses)
exactly. I understand this concept to be true, but the why still escapes me