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School me on mid-arm vs long-arm

psrivats

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I'll ask again, can the frequency be changed without also affecting the rate or length of the spring? Does a change in the weight of the vehicle, change the frequency?

Theoretically ... To the 1st question - yes, by changing sprung mass. 2nd question, yes.

The complicated part in all this are the shocks, since they dampen that frequency affecting what you feel inside the vehicle.

I think the shocks/spring combination is what matters. Remember that question I asked about JK/JL suspension a while ago?
 
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someguysjeep

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can frequency change without effecting spring rate or length?
for us, with a standard spring shock combo, not much if any.
i'd suspect adding a tune-able shock is close as we can get without playing with a pile of springs or accurate weight vs load info.

does this change with weight?
since a weight change would warrant a valve adjustment and/or possibly a spring extension/rate increase to hold height. then the answer is yes.
 
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AndrewLJR

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Love these discussions, not sure why people get bent out of shape. This is invaluable for knowledge purposes. Ive always questioned how much the weight of the Jeep vs the spring rates effect ride. I don't have the knowledge some of you have but Im intrigued where this thread is going
 
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jjvw

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... without playing with a pile of springs or accurate weight vs load info.

...

If we have a pile of springs, and we have created the desired ride height and the needed length to support the travel, what else is to done with the springs?
 

fixmysix

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I understand that. And the frequency seems to be related to the spring's rate and length against the weight of the vehicle.

I'll ask again, can the frequency be changed without also affecting the rate or length of the spring? Does a change in the weight of the vehicle, change the frequency?

Another irritating question meant to provide some context, how much suspension travel does a typical passenger car have compared to a typical F1 racecar?
The length of the spring doesn't effect frequency. It is a byproduct of desired spring rate, vehicle weight, and desired suspension travel. The relationship between weight and frequency can be shown in a simple experiment. Take a spring not in a vehicle and put it in a vice. Compress the spring a bit and release it. It will almost vibrate because it's natural frequency without any weight is so high. Put the same spring in the vehicle without shocks and jump off the bumper. It will move slow enough now you can count the frequency (cycles per second). I think the next relationship to be understood is front/rear frequency vs wheel base and speed to prevent that bucking sensation. Something Currie probably got right.
 

kmas0n

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If we have a pile of springs, and we have created the desired ride height and the needed length to support the travel, what else is to done with the springs?

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jjvw

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The length of the spring doesn't effect frequency. It is a byproduct of desired spring rate, vehicle weight, and desired suspension travel. The relationship between weight and frequency can be shown in a simple experiment. Take a spring not in a vehicle and put it in a vice. Compress the spring a bit and release it. It will almost vibrate because it's natural frequency without any weight is so high. Put the same spring in the vehicle without shocks and jump off the bumper. It will move slow enough now you can count the frequency (cycles per second). I think the next relationship to be understood is front/rear frequency vs wheel base and speed to prevent that bucking sensation. Something Currie probably got right.

What do we do with this knowledge when we select springs?
 
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someguysjeep

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If we have a pile of springs, and we have created the desired ride height and the needed length to support the travel, what else is to done with the springs?

you could find your preference. the rest of the pile is moot until changes cause needs. beyond that you have no control over how it behaves other than being able to add tune-able shocks to compliment.
exactly what a guy with CO's has to do. he has the advantage of split springs and tune-able shocks that most/we do not.

and this is the trouble with the spectrum from light duty to heavy duty and no real standard to differentiate. contributors info based on unknown corner weights...... leads me to the pile of springs.

and then peel all this back to general purpose none of this crap matters on a crawler (has diff needs), this is go fast BS. the sets are different because they are not the same..........

i hope to be taking the last pair of dump truck springs off my rig soon.
 

fixmysix

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What do we do with this knowledge when select springs?
We have to determine our desired travel at the spring and select a spring that will achieve at least this number without going in to coil bind and without becoming uncompressed/free. We need to determine our corner sprung weight and find a spring the will give us the right ride height we want under weight. Multiple springs can accomplish this which is where frequency comes in to play. Longer softer spring or shorter stiffer spring? Do we need to move a spring mount to achieve the travel and frequency we want? That would be my guess as I'm an old school leaf spring guy and still learning coil tech.
 
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Rock Toy

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So you're all saying that I should go with a mid-arm then. Got it 😂. After all of my research, I agree with the argument for a 30"ish LCA. Looks like it would be super nice to have longer arms IFI was bombing through the desert at high speeds but for the sake of "crawling", a mid-length arm is most likely better. I'll update you guys on my progress once I get started.
 
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jjvw

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So you're all saying that I should go with a mid-arm then. Got it 😂. After all of my research, I agree with the argument for a 30"ish LCA. Looks like it would be super nice to have longer arms IFI was bombing through the desert at high speeds but for the sake of "crawling", a mid-length arm is most likely better. I'll update you guys on my progress once I get started.

You're still hung up on arm length.
 
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Rock Toy

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That must mean that you are actually focusing on the mount locations instead.

Kind of. I think that I am simply going to go with the same mounting locations and arm lengths as the Savvy kit. The more I read, the more sense it makes to put the mounts in that exact spot.
 
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BuildBreakRepeat

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Kind of. I think that I am simply going to go with the same mounting locations and arm lengths as the Savvy kit. The more I read, the more sense it makes to put the mounts in that exact spot.
You also have the option to just get their bracket kit without the arms, but if you are doing the same mounts and arm length why not get their setup? Also, that suspension won KOH a couple of years back which includes lots of go-fast sections.
 
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Rock Toy

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You also have the option to just get their bracket kit without the arms, but if you are doing the same mounts and arm length why not get their setup? Also, that suspension won KOH a couple of years back which includes lots of go-fast sections.

Didn't know that I could get individual brackets from them. Regardless, I got a set of Ballistic Brackets which are pretty much the same except they have adjustable upper mounts. Maybe I'll hit them up for the front 3 link bracket when the time comes to do the front. One step at a time for me. I think I just convinced myself to tackle the shock outboarding while I'm working on the rear.
 
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BuildBreakRepeat

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Didn't know that I could get individual brackets from them. Regardless, I got a set of Ballistic Brackets which are pretty much the same except they have adjustable upper mounts. Maybe I'll hit them up for the front 3 link bracket when the time comes to do the front. One step at a time for me. I think I just convinced myself to tackle the shock outboarding while I'm working on the rear.
Looking forward to seeing what you come up with!