Outer Limits 4x4 Board

looking into custom length springs with extended chassis just wondering how i work out if im going to run 2' extended shackles how much longer i can make the spring to get the correct shackle angle

It really depends on the stiffness of the spring and whether under compression it will flatten completely. spring length should be the distance from the front mount to the rear + shackle length - 15mm this way when totally flat the shackle is not inverted

Sorry double post

Thanks mate that's pretty much exactly war I wanted to know. Is it a straight line from mount to mount. Or is it a horizontal measurement from mount to mount

i just put rears up front with the climax shackles everyone hates as they are an L shape when closed and dont require anything else to be changed.
Rides and flexes heaps better, dont know if ill ever unpin them tho but it was just an easier way of running a longer spring up front.

Will this be engineered? as extended shackles are illegal.
What length springs are you aiming at? I'm currently putting feroza rears in mine which are ~6-7" longer than std zuk rears. I'm keeping the std shackles though.
I've had to extend my chassis obviously so I could get some measurements and/or photos if you'd like.

post up some pics up of the foroza spring, r they 50mm wide?

nuh there 60mm. they still fit in the solid pin hangers though. And if your lengthening the chassis you'll have to make new shackle mounts anyway. I'll get some picks up tomorrow, im heading out for a beer now

ZUKPOWER wrote:nuh there 60mm. they still fit in the solid pin hangers though. And if your lengthening the chassis you'll have to make new shackle mounts anyway. I'll get some picks up tomorrow, im heading out for a beer now

do you just use the diff mounting plates (can't remember their correct name) from the feroza.

just cruizin' wrote:

ZUKPOWER wrote:nuh there 60mm. they still fit in the solid pin hangers though. And if your lengthening the chassis you'll have to make new shackle mounts anyway. I'll get some picks up tomorrow, im heading out for a beer now

do you just use the diff mounting plates (can't remember their correct name) from the feroza.

diff mount plates??? as in the plates that the u-bolts go through? I had to make some new ones as I didn't get any with my springs. I cant see why you wouldn't though.

not to worried about the legal part with this as im running a 35' tyre anyway.

so if i run 2' extended shackles all round then i sould be able to get a spring with significant difference in length.

sorry for dodgy diagram.
just want to confirm, if i measure A (mount to mount)+B (shackle) it should = C (spring) - 15mm.
c being a measurement of the total length not the bush to bush straight line. so a curved measurement as shown in diagram

you know really, your best bet it to mount the leaves in there minus the shackle and drop in a steel plate (one each side) with multiple holes in it so you can adjust its length - from this you can find at which point your shackle is at 45degrees under full weight and get custom shackles made up based on that measurement.

Sure, its trial and error - but it beats stuffing up the maths =) haha

alien wrote:you know really, your best bet it to mount the leaves in there minus the shackle and drop in a steel plate (one each side) with multiple holes in it so you can adjust its length - from this you can find at which point your shackle is at 45degrees under full weight and get custom shackles made up based on that measurement.

Shackle angle is completely irrelevent when calculating how long the shackles should be. Once the shackles are the correct length for the spring length and mounts, the angle is nothing more then a direct result of the arc in the spring. If the shackle angle isn't to your liking, you should be changing the arc in the spring to suit, not the shackle length.

mcwilly wrote:not to worried about the legal part with this as im running a 35' tyre anyway.

so if i run 2' extended shackles all round then i sould be able to get a spring with significant difference in length.

sorry for dodgy diagram.
just want to confirm, if i measure A (mount to mount)+B (shackle) it should = C (spring) - 15mm.
c being a measurement of the total length not the bush to bush straight line. so a curved measurement as shown in diagram

No C + 15mm, you want the mount seperation plus the shackle longer the then the spring so even when the spring is flat the shackle won't invert. Sorry if I was unclear.

So if I follow this calc I should have longer springs longer shackles and correct shackle angle (45) and more flex

Here's a few pics of my current headache
Leaves are 46" long

Rear chassis extension


New rear shackle mount


Pic of the spring in place


All flexed up

what a shitta

redzook wrote:what a shitta

yeah i had some dodgy advice from my neighbour

mcwilly wrote:So if I follow this calc I should have longer springs longer shackles and correct shackle angle (45) and more flex

That depends on a lot of factors, spring arch, spring rate, weight on the springs. Best thing would be to tack them on and load it up. But with this calc you won't invert your springs

ok well i did a bit of measuring today. my current standard springs are 40mm shorter then the combined length of the mounts + the shackles. which makes me believe that if i measure the mount to mount + the 2 inch extended shackle and subtract 40mm i should come up with a pretty good package. next issue is how do i make sure the new springs will be the same heaight to clear my tyres as i am borderline at the moment with clearance.i fi say i wan the same height as a standard suzuki spring when its X amount longer they shaould be able to do it? this is so complicated. might have to come check yours out zukpower

Dont forget the longer the spring the more they will bend with the same load if the spring rate is the same. Hence you will want something slightly stiffer, that can be achieved by running an extra leaf.

Yea sweet sounds easy enough. Has anyone done it this way before with just longer springs and shackles if so what results did you have

I did it with mine, although not quite as mathematically as you, I just extended them and worried about the shackles later Have you talked to a spring manufacturer yet ? The first set I just got extended and used the same specs as stock as said they were fairly soft but flexed very well. The 2nd set I neglected to tell the supplier what vehicle they were for and so they were set too stiff

I only got the main leaf extended and would advise getting the 2nd leaf done as well if you arent doing the whole pack. It is a matter of trial and error and currently my packs are made up of old and new leafs and ones I have cut up and whacked in there.

have you got pics of yours flexing vr rodeo? also do you remember how much you extended them by and what your shackle length is? that way i can have an example of what works and compare it to the standard ratios and make up m own

thanks
chris

These were taken just after I finished putting them in, from memory they were about an inch over stock rears eye to eye length alround. The fronts were good however I reused the stock rear shackle mount and with the soft leaves I needed a 4 inch extended shackle to keep it level with the front. And as you can see the rear binds up on the bushes before the springs really start to flex

Oh k cool. I was thinking maybe 2" longer then fronts in the front and 2 inches longer then rears in the rear. This was a 2" extended shackle might keep it working properly