rear 3 link coil conver

[tuff_89zook]

hey i was just wondering if any body has any plans or anything to put the rear axle on coils i have a spare housing and was hoping to do this now i have finished the front of the car and i have looked in the bible and couldnt find anything
cheers for any help
tuff_89zook

[ofr57]

have a look though general tech, pirate4x4 and also redzooks build up in the members page

[zookimal]

I thought you were selling this thing?

Do as ofr says.

I've been discussing this a bit recently and decided that if it isn't done right it'll destroy the balance of the car.

[ofr57]

the only reason I've heard of people doing coils in the rear only and leafs up the front is to do with hill climbs to stop the nose from lifting up or something along those lines

In my opinion something like an anti - rock sway bar system would fix that.

[11_evl]

i have coil rear and leaf front. work ok for me.
im running 3 link with panhard (2 lowers and 1 upper)

what did you want to know??

[Gwagensteve]

Have a search for suspension calculators in Pirate.

If you don't freak out with COG, instant centre, roll centre, antisquat, roll stiffness etcetc then by all means go for it.

This is a very signficant modification, and the coil sierra is evidence that even the factory, with all their budget and engineers, don't always get it right.

Don't get distracted by loose, floppy cars with tyres hanging feet below their body- these are rarely drivable or really good at anything except posing and impressing their owners, especially if the front is still leaf and has low flex. It's all about balance and predictability. Cutting the leaves out the back means that balance and predictability are now all down to how well you design the suspension.

Don't rule out a radius arm design that uses a range rover front arms and a panhard rod - it sorts antisquat and instand centre for you and will almost guarantee decent roll stiffness to work with a leaf front if you get the springs in the right spot. ( acutally, that's the design that 11_evl describes)

*Hijack on*
Personally, I don't understand why everyone is obsessed with coiling the rear before the front. it's the front that needs to move freely and accurately - far moreso than the rear - cars climb far better when the rear end is stable and basically on the bumpstops. However, the front is much harder to do, which might have something to do with it.
*hijack off*

Steve.

[Donald2]

Put a 4-link its easyer to do if you eant any help send me a pm

[/url]

[Gwagensteve]

Put a 4-link its easyer to do if you eant any help send me a pm

[/url]

There's no way a 4 link is easier than 2 range rover radius arms and a panhard rod.

That's before you crunch all the numbers on link placement.

Steve.

[11_evl]

Put a 4-link its easyer to do if you eant any help send me a pm

[/url]

There's no way a 4 link is easier than 2 range rover radius arms and a panhard rod.

That's before you crunch all the numbers on link placement.

Steve.

when you talk about 2 range rover radius arms, you mean the same set up as a GQ front??, if thats what your refering to i cant see why anyone would CHANGE to that as its crap in a GQ and would be no better in a sierra..
im running similar to a GQ rear but with only one upper arm in the center.
still with 2 lowers and panhard.
yes I think the reason why ppl do rear b4 front is how easy it is to do ( not that its that EASY to do), much easier than the front i guess. ill let you all know soon, i got bundy diff to go in front of mine to match the rear

[Gwagensteve]

when you talk about 2 range rover radius arms, you mean the same set up as a GQ front??, if thats what your refering to i cant see why anyone would CHANGE to that as its crap in a GQ and would be no better in a sierra..

Your right, radius arms are carp in the front of pretty much everything... because when your climbing, all the weight is in the rear and the bushing bind inherent in the radius arm design means the front won't flex.

However, back a GQ up a ramp and the front end works beautifully - because there's enough load on the front to squish the bushes and make provide the front with some roll stiffness. Rover front arms are better as they have a pin at the chassis end, one less bush to squish up.

My Gwagen runs radius arm front and rear and the back end works pretty well. It jacks a bit, but it's HEAPS better than most of the overly floppy 4 link designs I've seen. It also suffers from the too high COG of the back of my G- blame that on lots of steel and glass way over the back end.

Steve.

[zookimal]

Put a 4-link its easyer to do if you eant any help send me a pm

[/url]

There's no way a 4 link is easier than 2 range rover radius arms and a panhard rod.

That's before you crunch all the numbers on link placement.

Steve.

when you talk about 2 range rover radius arms, you mean the same set up as a GQ front??, if thats what your refering to i cant see why anyone would CHANGE to that as its crap in a GQ and would be no better in a sierra..
im running similar to a GQ rear but with only one upper arm in the center.
still with 2 lowers and panhard.

Steve suggested this to me the other day and I think it's a good idea.
I'm looking to link the rear of mine for more wheelbase and don't want to create a car where the rear flexes right out before the front starts to do anything. It was more to do with balancing roll stiffness front to rear in the car and a radius arm setup would achieve that perfectly.

That said, I've only seen one or two pics of your car since you linked the rear and the shots I saw it looked pretty balanced.

[Dee]

Put a 4-link its easyer to do if you eant any help send me a pm

[/url]

There's no way a 4 link is easier than 2 range rover radius arms and a panhard rod.

That's before you crunch all the numbers on link placement.

Steve.

when you talk about 2 range rover radius arms, you mean the same set up as a GQ front??, if thats what your refering to i cant see why anyone would CHANGE to that as its crap in a GQ and would be no better in a sierra..
im running similar to a GQ rear but with only one upper arm in the center.
still with 2 lowers and panhard.

Steve suggested this to me the other day and I think it's a good idea.
I'm looking to link the rear of mine for more wheelbase and don't want to create a car where the rear flexes right out before the front starts to do anything. It was more to do with balancing roll stiffness front to rear in the car

I was about to type the same thing!
I'd like to coil/link the rear to balance the rear flex to the fronts a bit more. Also to stretch the wheelbase.
Only thing is i'd end up wanting to do the front as well for 1. more wheelbase (and more balanced wb - mid engined feel type thing) & 2. approach angle...!

other issues - (more to do with wheelbase than coil conv, but i wouldnt be bothering with a coil conversion without stretching the wb at the same time)

fuel tank location & filler
shock mounts
bumpstopping
brakelines/handbrake
driveshaft
guard work (extensive..)

[11_evl]

coling rear, my main problems are/were
fuel. tank, cant really go too far back, not as much as i wanted anyway.
exhaust. once you got springs and shocks and vit tank i didnt have much room for an exhaust.

other things i have found is, nothin on the sierra chassic is strong. i have singl sheer arms onto the chassic with crush tubes and it has just bent and ovaled the tubes and cracked around where i welded.
my upper arm mt is starting to bend, it has started to tear itself out (im using a 2"round bar with L plates either end welded to chassic)

link seperation is a key factor not enough and you get lots of warp with busted unis, thats still keeping parallel. changing to a bit more seperation on the diff end and itwants top wheelstand all the time. because im still keeping to the SWB body space is a key factor to getting it all in there without cutting to much out
all in all great mod but without the time to refined shock choice and location, it can still be a shit ride

[GRPABT1]

the only reason I've heard of people doing coils in the rear only and leafs up the front is to do with hill climbs to stop the nose from lifting up or something along those lines

In my opinion something like an anti - rock sway bar system would fix that.

Or a shackle reversal

[Gwagensteve]

Which is why all the time with the 4 Link calculator is important. The shorter the wheelbase and the higher the lift, the less latitude you have for error.

I haven't had a problem with sierra chassis strength, but I doubling plate EVERYTHING and it leads to some pretty time consuming and complex connections to ensure chassis strength is maintained and the loads are well distributed.

Trial and error 4 link building is a pretty hard way to do it. It's at least part of the reason I haven't bothered with coils yet, but I think with the current build we might have taken leaves on a sierra as far as they can reasonably go.

Please don't think I'm having a go 11_evl - you've ponied up and done something I haven't, and props to you for admitting yours isn't perfect, but that's the kind of behaviour I'd be pretty keen to avoid after all the work.

I'm going to have a hard look and range rover front arms though. I'm starting to like the idea of a radius arm/panhard N76 coil rear end, I just have to try and figure out how to get the right roll stiffness and ensure clearance etc is maintained.

Steve.

[11_evl]

dont apoligise, i dont take much serious, esspecially from an internet forum.
im getting out there and trying things, its not a daily and its not something im building for someone else. and i cant afford to let others build it for me.

as for the chassis, im surprised how weak it is with no bracing. im foreva fixing up my under engineered attachments

just a few pics




it stays pretty level when flexed, im sure the front can go a bit more.



feel it to be very stable in big pot hole type terrain, car stays level but not so good on hilly side slopes

[grimbo]

It looks nice and balanced on the ramp but how does it feel when driving? Is it a nice balanced 4wd with predictable flex and climbing characterisitics or does it tend to flex abit then suddenly unload?

[Gwagensteve]

Have you got a photo driven up the ramp forwards?

That's going to explain a lot more about the balance of the car - 80 series and GQ patrols flex really evenly when backed up the ramp.

Steve.

[11_evl]

i hear alot about unloading and i dont realy know what that means
to me it feels great. especially when following other cars, suzukis as well, and i just drive over stuff that they are all lifting wheels and having 'monents'
but in saying that i have only ever built one car and and only been in a few over the 18months i have been into 4wds.
my only real problems with my set up is shocks and bumpstops and spring choice
i need more time to get them all to work together happily

[11_evl]

thats probably about the best i have, ill keep looking

[Gwagensteve]

hehehe - that's unloading

"Unloading" is the point when the car goes from feeling stable and planted to feeling light and spooky.

most people think more travel fixes this, but generally, it doesn't - some cars stay so planted feeling with a wheel off the ground you can't tell when a wheel is up until your spotter tells you - some cars feel spooky the moment a wheel lifts.

Weight distribution, wheelbase, height, roll stiffness, travel, GOG, antisquat - there's lots of things that influence it.

My G feels fine up to a big compound angle, then it feels like it's going to kill me. I still hate the way it feels, but in the case of the G, it's got a bit to do with high antisquat and more to do with a high COG in the rear.

RUF SWB sierras with bumpstop spacers in the rear seem to be able drive through about anything and feel pretty good. That's because the back goes to the bumpstops when the car climbs steeply and the rear stays planted. It takes a really big side angle to make the rear unload as there's normally a lot of weight on both bumpstops.

The current build I'm working on will have the same bumpstop height but they are inboard (inside the chassis line) and MUCH more droop. I think it will be great but it might be a little looser in the rear. This particular car will have a 98.5" WB so it should climb great, but in a SWB it might be too soft and loose in the rear.

For me, it's all about trying to make the car feel predictable on big angles, because if you can take the car into a really big angle and it works with you, hard stuff gets easier and more radical lines become possible.

Have a look at some old school rockcrawling from the late 90's, and compare it to recent stuff - the way the cars might not have as much travel but stay sooo planted and stable under power and on big angles.

Steve.[/u]

[GRPABT1]

I hear what you're saying big time Steve, I'm trying to keep the same "sure footedness" with my 3/4 elliptic rear. I have found so far (albeit with way to short shocks) that with little up travel through bumpstop spacing keeps it nice and stable up steep hills. But when I am crawling really slow uphill and hit a big hole on one side with the extra droop it doesn't wan't fall over as easy.

[Donald2]

[Donald2]

http://www.zookaction.gr/forum/viewtopi ... c&start=45

[11_evl]

nice rig Donald2

do you think he gets much axle wrap with his front upper arm set up like that

[joeblow]

doing coils right is a huge job. vehicle weight, spring rates etc all have to be worked out. you either stick with 4 leaves, or 4 coils, mixing the two is not the best option. for ease of engineering stick with 3 link front, and if you do what you like with the rear make sure you have your geometrey right. sierra chassis are pretty strong, its when people weld stuff to them without knowing how arms may work that leads to cracks etc. and don't forget bumpstops. all the coils set-ups i have done run two sets of stops fron't and rear, for normal road driving and off-road articulation. some of the pics i'm seeing here don't seem to have any. like i said if you want it to be nice on and off road take your time and do some research, it will save you some headaches in the future.

[mrRocky]

sounds complicated. i've always wanted to chop the rear coil setup out of a lada (only good thing on a lada mind u) and weld on my sierra. i figure they flex alot and are a similar sized vehicle so should make it easier.

[lump_a_charcoal]

Donald, nice rig mate!

Is that the Rocky Road kit?

[Donald2]

Donald, nice rig mate!

Is that the Rocky Road kit?

No it isnt the rocky road kit , its a home made , i was workng on it about 2 months

[lump_a_charcoal]

Very nice work then mate!

That setup on the front, with the diagonal brace to the diff, does it eliminate wrap?