Panhard Rods and Roll Centres

[me3@neuralfibre.com]

When I tested the rear of my Cruiser http://neuralfibre.com/paul/?p=89 for suspension travel I found the downward travel was limited (with shocks disconnected) by bush compliance in the upper and lower control arms. These were loaded heavily sideways by the panhard rod. The swaybar did not limit down travel.

A quick fix would be a longer panhard rod, but the "at rest" angle being off horizontal yeilds a larger side to side movement of the diff than is ideal.

The immediate solution is to fabricate a panhard rod drop bracket, and place the at rest body mount level with the axle mount yeilding a horizontal bar. This however (googling) will have negative impacts on the rear roll centre. There are two effects. One is that the roll centres are relational front to rear, and having th rear lower will have ??? impact. Having more body mass higher over the roll centre will also increase cornering roll in the rear.

Raising the axle mount point is difficult. It would require significant trussing to make a mount, and the panhard rod would have to be U shaped to avoid impacting on the exhaust and other chassis components.

Has anyone played with any solutions to this? I knwo chassis dynamics are a never ending rabbit hole, but I figure a few of the custom builders kicking round here would have some thoughts.

Thanx
Paul

[mud4b]

how about using a watts type panhard...

on the buggies here both panhards have been made longer than normal, and mounted on opposite sides of the chassis front to rear, they are also negative.

[lay80n]

Tri- 4 link, therefore no panhard needed

Layto....

[me3@neuralfibre.com]

Tri- 4 link, therefore no panhard needed :D

Layto....

I have thought about it. I love the Disco suspension design, can't see any downsides to it. Little hard to fabricate as a quick mod to the wife's car however.

Paul

[KiwiBacon]

Tri- 4 link, therefore no panhard needed

Layto....

I have thought about it. I love the Disco suspension design, can't see any downsides to it. Little hard to fabricate as a quick mod to the wife's car however.

Paul

The downside to the rangie style 3 link is rear bump steer.
It's never worried me, but some people really hate it.

[me3@neuralfibre.com]

Tri- 4 link, therefore no panhard needed :D

Layto....

I have thought about it. I love the Disco suspension design, can't see any downsides to it. Little hard to fabricate as a quick mod to the wife's car however.

Paul

The downside to the rangie style 3 link is rear bump steer.
It's never worried me, but some people really hate it.

Hadn't found that comment when I searched for comments on the design. Can you explain? (Big words are fine, most ppl here can handle them)

Thanx
Paul

[KiwiBacon]

Tri- 4 link, therefore no panhard needed

Layto....

I have thought about it. I love the Disco suspension design, can't see any downsides to it. Little hard to fabricate as a quick mod to the wife's car however.

Paul

The downside to the rangie style 3 link is rear bump steer.
It's never worried me, but some people really hate it.

Hadn't found that comment when I searched for comments on the design. Can you explain? (Big words are fine, most ppl here can handle them)

Thanx
Paul

Quite simple.
It's got a higher roll centre than most (central ball is maybe 100mm above axle centreline). So a bump lifting one wheel pushes the rear of the vehicle sideways more than your average rear suspension.

[Gwagensteve]

Can you explain? (Big words are fine, most ppl here can handle them)

Thanx
Paul

Hmmm you really know how to win friends

Not eveyone has to alienate half the board to ask a question. You pose some interesting questions, but you don't have to remind us of how literate you are with every post.

Steve.

[me3@neuralfibre.com]

Sick of being attacked for using my head. People get all defensive when they have to think about adjusting their pre-conceptions. Needling them in return is a petty outlet, but it is an outlet.

Forum exists to share knowledge, and I share all I can. my website shows that. I dont know any other way of saying F*ck off unless you have a clue and are prepared to contribute.

But you are right, I shouldn't feed the trolls.

Thanx
Paul

[ludacris]

By lowering the pahnard mount on the chasis your pahnard will become more vulnerable to getting bent and smashed up.

By the sounds you dont have a large lift so your shockies would stop the truck from flexing as much as a 80 with a 6 inch lift. A 80 with a 6 inch lift does not need what you are talking about so I would just leave it alone. But if you are really concerned why not change the bushes on one side of your trailing arms to a more flexing bush(cannot think of what they call them) to alliviate the problem.

LudaCris

[me3@neuralfibre.com]

By lowering the pahnard mount on the chasis your pahnard will become more vulnerable to getting bent and smashed up.

By the sounds you dont have a large lift so your shockies would stop the truck from flexing as much as a 80 with a 6 inch lift. A 80 with a 6 inch lift does not need what you are talking about so I would just leave it alone. But if you are really concerned why not change the bushes on one side of your trailing arms to a more flexing bush(cannot think of what they call them) to alliviate the problem.

LudaCris

I'n not sure what you mean by not a problem with a 6" lift? If you look at the pics and explanation in the top article, the diff will not drop any further without force, and that's with shocks and springs disconnected. I can only assume that the 6" lift springs force the bushes further outof compliance?

Paul

[chimpboy]

Sick of being attacked for using my head. People get all defensive when they have to think about adjusting their pre-conceptions. Needling them in return is a petty outlet, but it is an outlet.

I think you will find that people lose interest in helping you when you ask them questions, but at the same time implying that you are smarter than them and know much more than they do. You effectively deliver a message that says "There is nothing I can learn from you, but tell me what you know anyway."

This happened in your recent hydraulics thread where you had some basic misconeptions about how power steering and hydraulic winch systems interact, but were too busy assuming you knew everything to pay attention to the answers people were trying to give you. You told several people in that thread that they didn't have a clue what they were talking about; do you think they'll go out of their way to try and help next time?

And now you are assuming that people are defensive because you are making them "think about adjusting their pre-conceptions", when instead you could be adjusting your own and considering whether your attitude alienates others.

If you want people to share their knowledge with you, you need to be prepared to listen, and you certainly shouldn't start by insulting them.

Just my thoughts.

[hammey]

Sick of being attacked for using my head. People get all defensive when they have to think about adjusting their pre-conceptions. Needling them in return is a petty outlet, but it is an outlet.

I think you will find that people lose interest in helping you when you ask them questions, but at the same time implying that you are smarter than them and know much more than they do. You effectively deliver a message that says "There is nothing I can learn from you, but tell me what you know anyway."

This happened in your recent hydraulics thread where you had some basic misconeptions about how power steering and hydraulic winch systems interact, but were too busy assuming you knew everything to pay attention to the answers people were trying to give you. You told several people in that thread that they didn't have a clue what they were talking about; do you think they'll go out of their way to try and help next time?

And now you are assuming that people are defensive because you are making them "think about adjusting their pre-conceptions", when instead you could be adjusting your own and considering whether your attitude alienates others.

If you want people to share their knowledge with you, you need to be prepared to listen, and you certainly shouldn't start by insulting them.

Just my thoughts.

listen to chimpboy paul, he nailed it in the hyd's thread......

ps. two words....... be humble

[RUFF]

Sick of being attacked for using my head. People get all defensive when they have to think about adjusting their pre-conceptions. Needling them in return is a petty outlet, but it is an outlet.

I think you will find that people lose interest in helping you when you ask them questions, but at the same time implying that you are smarter than them and know much more than they do. You effectively deliver a message that says "There is nothing I can learn from you, but tell me what you know anyway."

This happened in your recent hydraulics thread where you had some basic misconeptions about how power steering and hydraulic winch systems interact, but were too busy assuming you knew everything to pay attention to the answers people were trying to give you. You told several people in that thread that they didn't have a clue what they were talking about; do you think they'll go out of their way to try and help next time?

And now you are assuming that people are defensive because you are making them "think about adjusting their pre-conceptions", when instead you could be adjusting your own and considering whether your attitude alienates others.

If you want people to share their knowledge with you, you need to be prepared to listen, and you certainly shouldn't start by insulting them.

Just my thoughts.

You really need to stop this CB.

Couldn't agrea more.

There are a hell of a lot of knowledgable people here that could answer almost any of your questions that wont because of the way you are replying to people that have a different opinion to you. You come across like you are looking for an answer that allready matches your opinion before you asked the question. Rather than looking for a different answer that is actually correct.

[Dak Dak]

Can you explain? (Big words are fine, most ppl here can handle them)

Thanx
Paul

Reading sh1t like that, several big words come to mind.

[me3@neuralfibre.com]

OK - seems my blunt manner is not helping to create a clear base of knowledge for the community.

Seeing as I am here to try and share knowledge, I'll refrain from any further comments or responses in my posts other than the initial thread start.

I will rely on others with more tact than myself to inidicate any inconsistencies in the replies. I hope this assists in building a more useful knowledgebase.

I have PM'd some of you offline to try and clarify what you view the purpose of outerlimits to be. All responses will be treated with respect.

Paul