[skitzlux]

Hey guys
I've recently done a ruf on my sierra buy cutting off the rear hangers flipping them and rewelding them on. I've put extended shackles on the front aswel with new bushes. I didn't do a chassis extension yet. I went to land cruiser park last weekend and after a day it had totally destroyed the shackle bushes when I turn the wheel the shackles move left and right quite badly. What could I do to fix this. I was thinking about a panhard bar maybe or do a chassis extension to correct the shackle angle and put poly bushes in it. What has everyone else done to fix this?
Thanks Brendan

[SierraDan]

Shorter shackles.
Mine does the same thing, but not as bad as you're describing.

I will be putting in a panhard.

[JrZook]

SierraDan wrote:

I will be putting in a panhard.

[skitzlux]

Does anyone have pics of how they did it I searched a bit and saw one setup here and it was like a z bar. Just wanted to know if anyone had used a oem part and made it fit. If not I found a spider tracks one but it's a straight bar and I'm not sure on clearance issues they are for spoa but they supposedly do a spua aswel thanks guys

[Gwagensteve]

You should be able to make a range rover panhard fit.

[just_cruizin]

A panhard won't fix the real problem. Leafs don't need a panhard and will actually cause problems as it's arc won't match the spring movement.

How long are your shackles?
Do they have a centre brace?
How much flex are you getting, do you want?
How many leafs are in the pack?

For leaf suspension to get heaps of flex you are going to chew bushes.

My suggestion, brace the shackles, ensure your mounts aren't flexing, add a couple of leafs and find a cheap bush supplier you will need one.

[Gwagensteve]

Ford and Jeep would disagree with you there just cruzin - they have both used panhards with leaves to improve steering response.

The longer the shackle and flatter the shackle angle, the more lateral movement you'll see in the axle.

Short bushing life is a byproduct of a flex RUF in my opinion. I don't personally believe increasing spring rate will do much to chafe bushing life or lateral movement. In my opinion it's coming from the bushes, the shackles, and the shackle angle, not from the leaves.

Just my 2C.

Steve.

[skitzlux]

My shackles are 130mm center of bolt to center of bolt
They do have a brace between them
I'm getting loads of flex which I want
And 4 leaves in the pack they are efs springs
I was gunna try and extend the chassis and put poly bushes in it first as they are on a big angle. I've had two other sierras that i did ruf on and this is the only one that really fucked the bushes. the other ones wore a bit but would take months before they needed replacing

Thanks for the replays guys

[JrZook]

just_cruizin wrote:

A panhard won't fix the real problem. Leafs don't need a panhard and will actually cause problems as it's arc won't match the spring movement.

The same issue is also in linked suspension. It will cause some binding in the leaf spring/suspension arm bushes at the extremes of the travel, hence the panhard is quite long; to create a large radius arc and minimize the forced lateral movement.

The real problem is inherent to the simplicity of the leaf suspension setup. It has to locate the axle (through the leafs/bushes/shackles) whilst still act like a spring and support the vehicle. A panhard will definitely help locate the axle laterally and be of little compromise to travel if well designed. Check out jdk81's thread. The front end on his seems to work quite with with a panhard.

[just_cruizin]

Steve,

Are you saying Ford and Jeep got it right. Just another work around to an engineering design issue

[Gwagensteve]

They know more about engineering than I do, and for their applications, obviously they felt one was required. Just putting out there that it is possible to use one in order to get the behaviour they were looking for, no reason we can't.

[just_cruizin]

Yet in so many other applications the design engineers decree they don't need one. The amount of design failures that both those companies have pushed through to production then followed up with 'patches'. The same as the media, just because they publish/produce it doesn't make it right.

It this situation a properly designed panhard may mask the real issue but I think redesigning the setup would be a better and easier solution. Push the mount forward, fix the shackle angle and the wandering will reduce

[SierraDan]

My mounts are forward, I don't have long shackles and the bushes are fresh.

But the leaf springs can only provide so much lateral control.

[JrZook]

just_cruizin wrote:

It this situation a properly designed panhard may mask the real issue but I think redesigning the setup would be a better and easier solution. Push the mount forward, fix the shackle angle and the wandering will reduce

Only up to a point as there will still be flex in the bushes + flex in the spring and shackles. It is inherent to the basic design and longer shackles will exaggerate it. Might meet the design criteria for a stock vehicle but who's to say it cannot be improved and that it is the best solution?? If something can be added to locate the axle laterally is it "masking" the problem or providing a solution to the inherent problem of the design??

Sounds like you are trying to follow a similar argument to adding a steering dampener to stop wheel shimmy. In this case wheel shimmy isn't inherent to the design and it is a problem stemming from else where (poor maintenance etc). Thus the damper will be "masking" the actual problem and is not a solution.

[just_cruizin]

Sure the panhard will stop the wander in the neutral position if that's where it is setup for however unless the chassis end is dropped considerably the travel end arc will differ to the spring movement thereby binding and flogging out the bushes in both the springs and panhard then you are back to square one.

Everything is a comprise in this game so I think in this case you are better off putting the engineering into getting what is there setup to work the best it can. Once you have exhausted those options look to additional supports.

So yes you are right I am making a similar argument as the old steering shimmer, in fact it's the same argument as steering shimmer can be a symptom of diff wander. I know heaps of sierras that have huge flex for a leaf vehicle that can quite happily run at 100km/h because thought has gone into the dynamics of the design. Others with the same basics are all over the place due to lack of attention to detail & design.

[JrZook]

Anyone got the eye-eye lengths of a panhard from either a coily or a jimmy so I can crunch some numbers for lateral deflection?

[SierraDan]

My car doesn't wander.
I want a panhard for a better steering input and when I'm jammed up against something and steering I'm just pushing the diff out of the car with the steering wheel which just annoys me.

It's only a want thing for me.
If the binding issues exist, then I'll just take the leaf springs out of the car.

[jdk81]

SierraDan wrote:

My car doesn't wander.
I want a panhard for a better steering input and when I'm jammed up against something and steering I'm just pushing the diff out of the car with the steering wheel which just annoys me.

In this instance the drag link is functioning like a panhard.
Leaf sprung diffs normally move side to side a shit ton, which is why you are always chasing it and changing steering input, and when bound up youre pushing the whole car sideways before turning.

Ill go and measure today, but with a panhard which is about the same length as the drag link the side to side movement isnt as much as the diffs normally move.

How much travel is there in the following instances?
stock travel
2" lift
ill measure my ruf

Ill measure my ruf from the passenger side chassis rail from compression to full droop.
The radius will be known.
We can then use the radius to determine where the others will be and how much they will move side to side due to the panhard.

[jdk81]

Based on drag link length = panhard length

Approx measurements, not at a computer today so used a string and tape measure.
travel measured at bumpstops, bit simplified but enough for our purposes.
200mm travel is 27mm side to side
150mm travel is about 20mm.
100mm travel is about 13mm

So at ride height being centered, at 200mm travel the sweep arc is less than 15mm.
Compared to no panhard, how much the springs move is negligible.

[JrZook]

15mm is jack all. You would get way more deflection just turning the vehicle on the road at speed. Looks like it would be beneficial to the spring bush lifetime.

Have you manged to road test yours yet jdk?

[SierraDan]

jdk81 wrote:

In this instance the drag link is functioning like a panhard.

Exactly. Which is what I don't want.

And your data there shows the lack of an issue a panhard is.

[jdk81]

No highway testing as yet, but initial testing is inspiring some confidence.

Sorry its taken so long, removing the body lift made everything so much more difficult to package.

[bally]

Grave dig. How did the panhard idea turn out?? Really want to do something for mine as well.

[jdk81]

It kicks so much ass.
My rig drives so nice and feels so smooth (i just wish it wasnt so loud).

Ill be doing a bolt on panhard for my daily tin top very soon

[Joshyboy26]

Is yours a custom length panhard jdk? Or is a factory panhard made to fit? Do you have any pics of the setup.

It seems like a good mid step between leafs and coils

[Gwagensteve]

Just for reference, the leaf cars I have built with Vitara power steering have all felt like they have slow steering - lots of turns lock to lock. The same pitman arm and steering box in my car delivers incredibly quick steering with zero play. That's the effect of the panhard. It's not the effect of the radius arms or coils as they provide no lateral location at all.

[Gwagensteve]

Most leaf sierras would struggle to have more than 8" of vertical travel, even with RUF, and their normal working range will be 1/2 that. With the panhard rod setup neutral at ride height, The maximum deflection of the axle left and right will be 20mm through that full 8" range of travel - which is the same amount a car without a panhard rod will be bump steering. From ride hight to full compression, the normal working range at speed, the deflection will be about 7mm.

Another advantage of using a panhard is a fixed roll centre. Leaf cars roll centre is imprecise and variable. with a panhard rod installed, it will be 1/2 way long the panhard rod. This will aid in tyre clearance.

[bally]

So those who have done it, can we get some pics please? Iv been casually looking at my front end and seeing clearances being tight between an armoured center and draglink/pitman arm... not a great deal of room there to build stuffs..

[Joshyboy26]

I remember talking to you steve about the slow steering in leaf cars, this may be the solution to keeping the car relatively simple yet still behave nicely and respond to steering inputs well.

[monley]

Not on leafs but fitment would be the same regardless. Thats a front Jimny panhard rod