Ramination
Rock Crawler
So, last night I got a little time to work on this thing again to prep for this weekend. I wanted to tweak my suspension a little, and go a little bit softer. Being a nerd (and engineer), I couldn't just try different spring setups. No, that definitely is out of the question, math must be involved.
My thought on suspension setup for something like this rig is to run the lightest spring rate as possible that will yield the ride height I am trying to achieve with ~0.25" of preload; this should limit the "unloading" the suspension may want to do in an off camber situation, I think. And then of course let the shock oil do the dampening duties, not the springs. I only mention this because it seems like this is NOT the strategy the majority of people in this community follow.
Anyways, in order to tune the spring rate down, I first have to know what the spring rates of these KING springs are. Since I couldn't find anything on this, I broke out the pen, paper and TI-89 calculator and did it myself. I wont bore you with the nerd stuff (shear modulus, Poisson ratio, etc...) but essentially you take the spring diameter, number of active coils and the coil thickness and throw them into an equation with the shear modulus and BAM...spring rate. I'll skip that unless there is some interest.
Once you have the spring rate of a spring, you can find the combined spring rate of two springs together using the formula = (Spring Rate A x Spring Rate B)/(Spring Rate A + Spring Rate B).
I then decided that I had might as well do it for as many springs I could get my hands on...because why not? So, fired up Excel and got to work measuring all I had. I don't have a lot of the Axial springs, but I would like to add them in if I can. I am going to start a separate thread asking for people who have these springs to get my the dimensions. The numbers in red are just guesses for now...
So I was set up with a Stock over Black 40mm King spring. (the 40mm springs are for the 110mm shocks, the 35mm are for the 100mm shocks), which results in a combined ratio of 1.595 lbf/in (according to my calculated spring rates, which may or may not be correct but the relationship will still follow). I wanted to go a little softer up front and a little more softer in the rear, so I went with a White on top of Black for the front (1.348lbf/in) and a White on top of Red in the rear (1.174lbf/in). These 3 conditions are highlighted in the chart.
Now typically I wouldn't want the individual spring rates of the two combined springs to be so far apart, and so for the front I originally tried a Stock over Red (1.357 lbf/in) but I actually didn't like how that flexed. For all intents and purposes, the Stock over Red and White over Black are essentially the same combined rate, but due to the individual rates they feel different. I know in the 1:1 world you typically avoid having a large difference between the two springs, however maybe this is something we can get away with in the 1:10 world.
I will break down corner weights are how that effects the shock/spring setup later, if there is interest. For now, chew on this (if you can read it, I uploaded it full size but photobucket isn't allowing you to view it that big).
I also got some Grip Fab V1 lockers in the mail yesterday and installed. Actually I only had the energy to install the front one. Rear later. Shit is tight now.
And finally, being married is paying off, soft top made and installed. :mrgreen: I like the soft top on there A LOT, because it helps hide my shitty interior work. :ror:
My thought on suspension setup for something like this rig is to run the lightest spring rate as possible that will yield the ride height I am trying to achieve with ~0.25" of preload; this should limit the "unloading" the suspension may want to do in an off camber situation, I think. And then of course let the shock oil do the dampening duties, not the springs. I only mention this because it seems like this is NOT the strategy the majority of people in this community follow.
Anyways, in order to tune the spring rate down, I first have to know what the spring rates of these KING springs are. Since I couldn't find anything on this, I broke out the pen, paper and TI-89 calculator and did it myself. I wont bore you with the nerd stuff (shear modulus, Poisson ratio, etc...) but essentially you take the spring diameter, number of active coils and the coil thickness and throw them into an equation with the shear modulus and BAM...spring rate. I'll skip that unless there is some interest.
Once you have the spring rate of a spring, you can find the combined spring rate of two springs together using the formula = (Spring Rate A x Spring Rate B)/(Spring Rate A + Spring Rate B).
I then decided that I had might as well do it for as many springs I could get my hands on...because why not? So, fired up Excel and got to work measuring all I had. I don't have a lot of the Axial springs, but I would like to add them in if I can. I am going to start a separate thread asking for people who have these springs to get my the dimensions. The numbers in red are just guesses for now...
So I was set up with a Stock over Black 40mm King spring. (the 40mm springs are for the 110mm shocks, the 35mm are for the 100mm shocks), which results in a combined ratio of 1.595 lbf/in (according to my calculated spring rates, which may or may not be correct but the relationship will still follow). I wanted to go a little softer up front and a little more softer in the rear, so I went with a White on top of Black for the front (1.348lbf/in) and a White on top of Red in the rear (1.174lbf/in). These 3 conditions are highlighted in the chart.
Now typically I wouldn't want the individual spring rates of the two combined springs to be so far apart, and so for the front I originally tried a Stock over Red (1.357 lbf/in) but I actually didn't like how that flexed. For all intents and purposes, the Stock over Red and White over Black are essentially the same combined rate, but due to the individual rates they feel different. I know in the 1:1 world you typically avoid having a large difference between the two springs, however maybe this is something we can get away with in the 1:10 world.
I will break down corner weights are how that effects the shock/spring setup later, if there is interest. For now, chew on this (if you can read it, I uploaded it full size but photobucket isn't allowing you to view it that big).
I also got some Grip Fab V1 lockers in the mail yesterday and installed. Actually I only had the energy to install the front one. Rear later. Shit is tight now.
And finally, being married is paying off, soft top made and installed. :mrgreen: I like the soft top on there A LOT, because it helps hide my shitty interior work. :ror:
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