Thread: Panhard rods

Originally Posted by c.h.i.e.f

So guys what's the bad points about adjustable panhards ? If an adjustable one is no good the only option left is to make a new one that is of a corrected fixed length and fit it ? Then of course there's the problem of proving to an engineer that the new one is as strong if not stronger than the original...Same as the dilemma I am having with trailing arms at the moment..

As Uninformed said............. you want the panhard rod to be as parallel as possible in both planes (vert and horiz) to the draglink otherwise you end up with bumpsteer.

An adjustable one will line up the front and rear wheels on each side but will not address the bumpsteer issue, except maybe if the draglink is lengthened as well.

Nexter's idea on the last page is interesting IMO. And 4" is a lot of lift. Maybe a combination of longer draglink, adjustable panhard and lifted panhard diff mount would address all issues.

DL

It may have been easier to fit 35's by running a 2" lift and heavily modifying the guards but oh well .... The swivels are currently setup on a jig in the dividing head ready to be slotted so that's sorted... The only problem I can see with extending the panhard diff end mount is your making the design weaker due to leverage...I would like a parallel 4link front and triangulated 3link rear but as previously stated the main thing the engineers want to see is if the component made is as strong or stronger than standard component but the problem is finding the strength/material used for the OEM parts...also if rose(heim) joints are mentioned all the engineers I have spoken to don't want anything to do with them

you dont need heim/rose/jonny joints for a good suspension. You need good design and some decent link length. Design is #1

If by triangulated 3 link, you mean the same as what is there now, then ok.....if not, what do you mean and why???

why run a parrallel 4 link when you could run a 3 link up front, both need a panhard rod.

IMO RA's are under looked and can be made to work very well.

Looking at the drag link and panhard rod, the drag link is already longer, so you dont want it longer again. If you where doing the whole thing properly, you would be making the wheel track wider at the axles, because you are rasing the COG by raising the vehicle.....this would allow the fabrication of a new, more outboard panhard chassis mount. But carefull design would have to be made to make sure it strikes the same arc as the drag link.....the drag link would also be longer due to axle track width increase, but the relation would be the same. If you rasie the panhard diff mount only you are now running 2 different lengths and angles for the panhard and drag link.....not a good idea at all. You also will raise the roll center more than just the lift. IMO you dont want the front RC higher than the rear.

as John said, get some oem trailing arms and get them hardness tested, this will tell you something. I can tell you that the RA are 1.5 times harder than mild steel....

regarding your castor, are you just going to return it to the stock 3 degrees or are you going to add more?

EDIT: BTW I am here to learn, I am no guru by ANY means. Many more here that know more than me and im happy to have any of my ideas pointed out as being wrong. This is serious stuff were peoples lives are involved.

3link that is of a better design than what is there as we both know the ball joint is the limiting factor and can be improved..the problem I can foresee with 3link is having the room between the chassis rails to achieve the correct angles to do away with a panhard..
I do agree with what you said about heims etc etc are not need for good flex but IMO rubber ones such as standard will only start to compare if the lengths of the arms are increased which will in turn mean there will be less angle at the mount or bush...I have never seen a buggy or truck that is setup for high flex that does not use heims,Johnny etc etc

As for castor I will be returning it back to standard.
I understand you are trying to help I appreciate it.... I am also wanting to try and keep things safe as possible unlike most Nissan owners and there huge lifts/mods that never get engineered or anything..

The problem with spherical rod ends (heims/rose, whatever you want to call them) is wear because they are difficult to seal properly and a lot of people drive about in vehicles that are not serviced properly. Then when they wear, they are prone to falling apart and if this happens with steering and suspension components at high speeds ....

You see these used in north American buggies but usually these are trailered on public roads, and their conditions are not as severe as here for wear of the exposed joints.

Land Rover rear suspension is not 3-link, it has 2 lower arms and an upper 'A' frame, nor is the front radius arm suspension 3-link.

A panhard is required with any 3-link suspension.

Originally Posted by Bush65

The problem with spherical rod ends (heims/rose, whatever you want to call them) is wear because they are difficult to seal properly and a lot of people drive about in vehicles that are not serviced properly. Then when they wear, they are prone to falling apart and if this happens with steering and suspension components at high speeds ....

You see these used in north American buggies but usually these are trailered on public roads, and their conditions are not as severe as here for wear of the exposed joints.

Land Rover rear suspension is not 3-link, it has 2 lower arms and an upper 'A' frame, nor is the front radius arm suspension 3-link.

A panhard is required with any 3-link suspension.

Mmmm there's 4 contact points with the chassis so yeah 3link was not a good statement... As for wear that's the greatest concern as you have stated which is why I do not want to make a irrational decision and go and buy heims etc etc and put anything at risk...I do believe a Johnny joint is much more suitable and more resistant to wear and has cushioning unlike the rose/heim joints and there of a much high strength design wise IMO..

By definition a link only carries axial load (tension or compression). The 'A' frame in our rear suspensions is not a link, neither are the front radius arms.

A free body in space has 6 degrees of freedom (3 translational and 3 rotational).

An axle needs to be constrained so that it only has 1 translation freedom (so it can move up and down for bumps etc.) and 1 rotational so it can articulate. To restrain the other 4 freedoms exactly 4 links are required. One less will allow an unwanted freedom and one more will confine one of the required freedoms. Some suspensions have extra links, but they can only work because they use bushes that deflect (up until they bind).

Spherical rod ends have no compliance.

A 3 link suspension usually has 2 lower links and 1 upper link. They need a panhard (or Watts linkage) to constrain the 4th freedom, so should really be called 4 link.

The 'A' frame constrains 2 freedoms, so effectively replaces 2 links. With the 2 lower links, all is well.

Each front radius arm constrains 2 freedoms and the panhard another, (5 in total ) so the front suspension is overconstrained and as most know, it requires compliant bushes and still doesn't flex as well as some would like.

To add what John has said, the rear end is called a A frame or wishbone with parrallel trailing arms. It can be considered a single triangualted 4 link when crunching some geometry numbers like Axle roll axis and anti squat. The roll center is the center of the ball joint.

The front Radius arms are like 2 parrallel links EACH side, these have their convergance point at the center of the chassis end pin bush. The roll center is the height where the panhard disects the chassis center line (when viewd from in front) Roll axis can be determined by drawing a line from axle center line (view from side) to center of chassis end pin bush.

The front end while not flexy does have the advantage of built in roll stiffness....a 3 link + panhard does not. They are simple and package well. LR seem to have the best RA when compared to Nissan and Toy. Im not sure about the G wagens.

D2 RA have bigger axle end bushes, there percentile increase over the standard rover RA is bigger than the percentile increase in bush seperation at the axle...so there fore should flex better. Im not sold on the chassis end of the D2......

the ball joint is not as bad as you think. You can make the trailing arms longer and not run into to much trouble if only going to a 12 inch shock... You could fab a new A frame that stepped up and out to the top of the chassis rails. The important part when considering the angle of the A frame is the distance of the 3 joints. That is the speration of the 2 chassis bushes and the distance back to the ball joint. The arms dont have to be in a straight line but if they have any bend in them they have to be alot stronger. Look at the angle of the chassis bushes on the A frame. they are angled so any side movement they will start to bind. The A frame is locating the rear axle laterally.