What is the method of figuring out the travel of a coil spring?

Lets say we are using a 5" Dia x 14" tall spring...175lbs spring rate ( or does the spring rate matter?)

What's up Shane? How ya been?

Good Disco, Wont be able to make it this weekend.....Zuk is in pieces...

http://www.pirate4x4.com/forum/attachment.php?s=&postid=956775

GET IT Buddy!!!! I don't think we're gonna go anyways. We may just have a party somewhere cause Sloppy is coming up from SD.

Originally posted by Disco
GET IT Buddy!!!! I don't think we're gonna go anyways. We may just have a party somewhere cause Sloppy is coming up from SD.

Well give me a call.....stop by and have some :beer: :D

No one knows......:confused:

Hey you forgot a spot.

I don't think there really is a method to the madness. Of course spring rate matters. The softer the spring rate the easier it will be to force the coils out of their natural resting position. Anyway I'm guessing you wanna know how much the coils willl stretch and compress for travel right? That would also depend on the width of you axler cause a wider axle with the same spring location will put more stress on the springs forcing them to pull and compress more. In essence the fulcrum/ spring changes. Anyway sorry I guess you could ask some math nut who might be able to figure all the equations out but I doubt he exists on this board. You would also have to take into consideration the point at wich the coil starts to resist pulling over how much your sami would be able to exert which seems like a near impossibility. In other words you have way to little info for anyone to make even a semi decent educational guess.

what spring track are you going to mount them at?

what i would recommend is compress the spring and messure how tall it is. with the standard high and the compress heigth you could would know how much travel the spring has. then depending on how far away from the WMS the spring is mounted, use that length in relation to the 2 messurements you got from the spring. also take into consideration any interference you might get from your linkage setup.
the closer to the WMS the spring is, the less flex you will get but it will be more stable, the farther away from WMS the spring is, the more flex you will get but less stable (same thing with leaf springs). From what i have heard, put the front springs farther out then the rear, it will make the rig more stable.

This is what i've heard from all my buddies that are into this stuff, it very well could be complete bullshit :D

Originally posted by ECF
I don't think there really is a method to the madness. Of course spring rate matters. The softer the spring rate the easier it will be to force the coils out of their natural resting position. Anyway I'm guessing you wanna know how much the coils willl stretch and compress for travel right? That would also depend on the width of you axler cause a wider axle with the same spring location will put more stress on the springs forcing them to pull and compress more. In essence the fulcrum/ spring changes. Anyway sorry I guess you could ask some math nut who might be able to figure all the equations out but I doubt he exists on this board. You would also have to take into consideration the point at wich the coil starts to resist pulling over how much your sami would be able to exert which seems like a near impossibility. In other words you have way to little info for anyone to make even a semi decent educational guess.

Well thanks for the response.....
Yeah i know it was a long shot, but I thought one of the math wizes would pop in..

probably not exactly what you're looking for, but this is a very good post about coil spring rates and such.

http://www.pirate4x4.com/forum/showthread.php?s=&threadid=87811

You can easily figure the point of coil bind by measuring the DIA of the wire and multiply by the number of coils. That's the final height, then subtract that from 14" free length. That's how far it is possible to compress. Streatch is another matter. Generally you can safely compress and streatch by 1/2 the free length or a total of 14" in your case without dammaging the spring. With a Zuke, it's unlikely you'll ever streatch a 175lb spring 7 inches (that would take 1225 lbs down force).

If you are interested in predicting the articulation, the coil spacing will be a controlling factor. How far out the coils are seperated and how wide the axles are set the leverage on the coils during articulation.

Ok,
I am not the most articulate guy, and I am not a math wiz.

Determine the mounting point of the coil at the furthest point outwards on the axle. This will give you the radius from the roll center for the measurement of articulation. Use max stretch measurement and apply that to the arc, this will give you the true flex measurement, remembering that your wheel is going to travel in an arc, not just down. There is also a formula on the rover board for converting spring/shock travel to wheel travel.

http://www.pirate4x4.com/forum/showthread.php?s=&threadid=56826&highlight=wheel+travel

Oh and that part about enough downforce to max compress?

Well I don't know about that. I know Zuk's are light, but off-camber one wheel centric leans can do funny things with weight distribution. Especially when crossed up.

A 170lb spring sounds rather stiff to me. I run 260-300 progressive on the front, and 300-360 progressive on the rear of my rig, and it weighs in at 6klbs. And it's STIFF.