A short course...

spnkzyj

Member 2022
I dig the info. It'll be something I come back to when it's relevant to me for R&D.

However, I do have a question. From a crawling standpoint, what are you looking for in a shock and/or shock tune? Higher speed stuff I get. Not much different than setting up a racing shock, just different wants/parameters. I mean, in theory, it's all about keeping the contact patch on the ground.

Only thing I've been able to come up with is bounce control. Guess it then turns more into how I want it to handle on the road. Once I figure out wha ti want I need to equate it to how it will work on a leaf spring. I'm sure I'll go coils in teh front one day, but I want to "own" the leafs first. Slider boxes will be coming soon I'm sure.
 

R3

Member 2022
Springs hold the weight of the vehicle no more no less. the trick is how you get there. For Coils the spring part is easy. single spring rates are calculated for the corner unsprung weight of the vehicle. Dual and triple are calculated in a slightly different way. Dampening is what the shock does. The valve stack is the key to controlling slow speed and high speed movement ( notice I said movement) You can create a valve stack that is soft to slow movements but stiffens up to high velocity movement. This applies to either crawling or high speed. In the high speed world, off road, most use a combination of coil overs dual and tripple rate and a 3-5 bypass shock in conjunction. where each by-pass is tuned for a specific movment. The goal of the shock is to keep the wheel in contact with the ground.

Leaf springs; one thick one or multiple thinner ones? Tapered or straight? Long or short? I have read a bunch of different apporoaches here. one that i like is using thinner leaves in a stack to hold the weight up on each corner. The key is to make sure the leaf straps or keppers are used and tight to keep spring wrap from entering into the picture. The movement is controled by a good quality shock or pair of shocks.

The thinner multi stack provides for a more compliant spring rate and is easily adjustable by adding or removing springs. The trick is to keep enough in the stack to defeat the axle wrap ( S shaping of the spring). Another component of leaf spring ride quality is spring length. Longer tend to be less harsh.

Tapered spring leaves tend to be singles or small stacks ( 2-3 leaves) these have a variable rate where as the ends are soft and flexable for small movments and the centers are thicker for weight carrying ablity and restricking large movements. Coil springs tend to have a better frequency response than Leaf springs due to design. Changes in spring rate for Coil over systems are also a bit easier as there are a lot of options out there along with manufactures. Leaf springs are tunable but the number of folks that are doing that is steadly disapearing.

OEM manufactures spring a vehicle for Max rated capacity. if the 3200# jeep is rated for 4500# GVW and you only run it at 3500 then there is 1000# too much spring rate for a given application.
 

R3

Member 2022
Sorry, back to you question,
What I am looking for is a good on road ride and the ability to control wheel movement off road. I want to keep the contact patch attached to the ground and dampen high speed movement when falling off a steep edge. a single coil over can provide this. Higher speed stuff need a by pass set up or a much larger shock to achieve the ride quality.
 
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