Kuma's EBK

[Kuma]

I know how you guys don't like reading, here are 3 videos, suspension on the EBK a couple years ago.
I welcome comments, then I'll pipe in, 'nuff said.

[Kuma]

No suspension experts here? okay, here is what I see, the rear suspension seams to spend too much time at or near full compression, not sure if that is just from a combination of going round a bowl, body roll and acceleration but it does not seem right to me, I can't tell if the main spring is ever coming into play by itself or do I just need stiffer springs, I'm going through the spring rate sticky but all the math makes my head hurt.

[Bullnerd]

Sorry dude, far from an expert here.

But , yup, back looks soft.

[K-fab]

Back does look a bit soft - where are your cross over collars set so the main spring takes over? Doesn't seem like I ever see the tender spring lock into place. Moving the collars down a bit should also help with body roll.

We need an expert here - hey bdk, thoughts?

[Kuma]

Ya, I don't see that it ever transfers onto the main spring either, IU need to get this sorted out without spending too much extra cash, if I run the numbers on a suspension spring calculator I see that I need something much stiffer but to me it doesn't seem like it could be that far off???
the other thing is the valving, there is valving in the coil over as well as the bypass, not sure but maybe too I need to lighten up the valving in the coil over or remove all the discs and just go with the bypass, then maybe I'd be able to feel more effect in making adjustments?

Currently the rear springs are 12" 150# on the bottom and 10" 150# on top, the length of the swing arm is 26" and the coil over is locates at 18.5" and it's about 25 degrees, unsprung weight is 70#

[plkracer]

Move your front preload rings down, or move The cross over up. The front is always on the main spring, you should be into the travel at least 2-3 inches before you hit the cross over.

Couldn't tell much about the rear valving, springs are soft, so crank down the preload and cross over rings to keep the shocks from nearly bottomed out. The bypass is is the stiff zone half of the time.

[Kuma]

the rear is where I think the biggest issue is.
I found this spring rate calculator online http://f-o-a.com/foa-suspension-calculator/
I have not weighed the car but from one of the other posts of a similar car I come up with a rear corner weight of 410# -70# (unsprung weight) add 30# for 1/2 of approximately 10 gallons of gas which is right over the rear axle, and add another 45# for splitting my weight by 4 plus a few for the extra engine weight and I come up with 415#, plug that into the calculator with 50% droop, not sure if that is right or should I shoot for something else?, It comes up with a overall spring rate of 142#/inch, and a 355#/inch and 257#/inch for springs, with my current dual springs it is at 75#/inch, could it be off by that much???

[plkracer]

You can calc the approximate weight of the corners by measuring the free and compressed length of the springs, then factor in the shock angles.

The combined rate from the calc is close to your single spring rate. You might try lowering the cross over collar and see how it feels with a single spring. It is going to coil bind if you run it hard though.

[Kuma]

So, I actually went to King and talked to one of the guys, I assume he knows what he was talking about but I’m not so sure?
He asked about how much preload in the springs to get the ride height, the guide line they use is 1 to 3”, I measured and If I understood what he was talking about, I’m at 1.5” sounds perfect right? It just seems too soft in the back especially seeing the video. I found a off road spring calculator on line and according to that I’m about ½ of where it should be, so who do you believe, I don’t want to dump $300 into a set of springs if not going to work. When I described the video and the the way the rear spring was fully compressed in the bowl, he said it needs more compression valving? To me the valving just controls the speed that the spring can move not how far it moves.
I also had the question on how much the pressure in the shocks effect the spring rate, ride height ect. With 150 psi in 2 shocks that amounts to 132 lbs that if I were to subtract that from the corner sprung weight of 410# that would probably make the current spring rate about right, right?
Confused??? Me too.

[Kuma]

had a great weekend at Glamis, love the off weekends, this was weekend after Prez day