Outer Limits 4x4 Board

Hi all

I'm running 80series axles under the front of my POS and i was thinking of putting something like this under it

http://www.actionjackson.com/cruiser/tr ... ilRunID=41

Basically i was going to keep the arms, and put in a removable top third link. Run the front two bolts on the road and remove them for off road. That way i still get a bit of roll control on the road and stability/predictability but then i can get even out the flex front to rear off road.

So some questions

If i put in the third top link, do you think it would bind or work against the other arms if i just left in all the time on the road? I don't mind putting it in and out when i want to go for a wheel, it's only a couple of minutes but it would be one less thing to worry about if it can stay in

johnny joints or bushes in the top arm?

I would make the top arm adjustable, but what sort of length in comparison to the bottom arms should i make it? Also what vertical separation from the bottom arms at chassis and at diff housing. How does altering these parameters affect handling and geometry?

Does it matter if the top arm is bent or contoured a la the drop torque arms in hiluxes? would be good for clearing stuff in the way like sumps and x members etc.

Other than flex how do you think it would go off road? Would it make side slopes positively scary? Do you think the flex limiting front end of the standard 80 goes a long way to stopping the car unloading on cross slopes? I'm thinking that the benefits of levelling the car out during flex instead of it following the front diff housing would be worth it.

I'm thinking this is a better option for me than an x link. It's less invasive, less obvious to the plod, reversable and enables going back to good road manners.

your input would be greatly appreciated

MILO

thats actually a four link. and are you talking about removing the bolts in the standard lower arms offroad?......if so bad idea as these are difficult to locate sometimes and will chop out bushes and mounts everytime it moves in and out of the bracket.

joeblow wrote:thats actually a four link. and are you talking about removing the bolts in the standard lower arms offroad?......if so bad idea as these are difficult to locate sometimes and will chop out bushes and mounts everytime it moves in and out of the bracket.

Bugger. hadn't thought of that.

Anyone got any ways around that?

I've seen a couple of the threads on the patrol forum about a guy who wanted to do something similar, but i havn't had much luck about finding what the road manners would be like with it in. particularly under braking and cornering

joeblow wrote:thats actually a four link. and are you talking about removing the bolts in the standard lower arms offroad?......if so bad idea as these are difficult to locate sometimes and will chop out bushes and mounts everytime it moves in and out of the bracket.

Nope, that is a 3-link.

And if you are going to do it, do it with the proper arms, not retro-fitting the standard items. Otherwise you are just wasting your time.

Three links with Johny joints or simular and add a sway bar for on the road with disconnect.

- David.

Dirty wrote:

joeblow wrote:thats actually a four link. and are you talking about removing the bolts in the standard lower arms offroad?......if so bad idea as these are difficult to locate sometimes and will chop out bushes and mounts everytime it moves in and out of the bracket.

Nope, that is a 3-link.

And if you are going to do it, do it with the proper arms, not retro-fitting the standard items. Otherwise you are just wasting your time.

Three links with Johny joints or simular and add a sway bar for on the road with disconnect.

- David.

lets see....in the pics it has one link either side....thats two....than there is one in the middle roughly( like a torque rod )...thats three.....plus the panhard rod....mmm...that makes for four as far as i can tell.

Dirty wrote:

joeblow wrote:thats actually a four link. and are you talking about removing the bolts in the standard lower arms offroad?......if so bad idea as these are difficult to locate sometimes and will chop out bushes and mounts everytime it moves in and out of the bracket.

Nope, that is a 3-link.

And if you are going to do it, do it with the proper arms, not retro-fitting the standard items. Otherwise you are just wasting your time.

Three links with Johny joints or simular and add a sway bar for on the road with disconnect.

- David.

Can you imagine getting johnny joints past dot in queensland. I think not.

I need it to be A. reversible in case it turns out to be crap or if DOT get shitty with it and B. Not look too much different to what my engineer has already signed off on

I had a chat to someone today who suggested i run a torsion bar style of sway bar and run a remote disconnect to it. That way i get roll control on road and on side slopes and max flex possible

joeblow wrote:
lets see....in the pics it has one link either side....thats two....than there is one in the middle roughly( like a torque rod )...thats three.....plus the panhard rod....mmm...that makes for four as far as i can tell.

You don't include the panard bar in the link count.

- David.

rockcrawler31 wrote:I had a chat to someone today who suggested i run a torsion bar style of sway bar and run a remote disconnect to it. That way i get roll control on road and on side slopes and max flex possible

This is a good idea. The more flex you work at making the more anti-roll you need to build into the system.

You can still go the 3-Link setup, but ditch the factory arms, though you can re-use the factory mounts, but make an arm with rubber bushes at each end using standard rear bushes. Using material in line with what is in place on the rear links and an engineer is going to be happy.

Most of the issues with getting through engineering is not the link design, it is usually the amount of lift that people want when they go to this much effort. Authorities aren't just keeping themselves amused by limiting lift to a couple of inches, they are actually thinking of eveyones safety.

There are also several threads around on 3 & 4 link setup's. Search here and generally on Google and you should find a heap of info.

- David.

Dirty wrote:

joeblow wrote:
lets see....in the pics it has one link either side....thats two....than there is one in the middle roughly( like a torque rod )...thats three.....plus the panhard rod....mmm...that makes for four as far as i can tell.

You don't include the panard bar in the link count.

- David.

umm.....i think you do............lets see.......a standard tojo or nissan front is a three link yes?....two control arms and panhard........that ='s three..not two.

The setup has commonly been known as 3-link + panhard.

Dirty wrote:

joeblow wrote:
lets see....in the pics it has one link either side....thats two....than there is one in the middle roughly( like a torque rod )...thats three.....plus the panhard rod....mmm...that makes for four as far as i can tell.

You don't include the panard bar in the link count.

- David.

You better tell nissan/toyota/landrover/jeep as they all count the panhard in their suspension advertising.

It's not a pissing competition

joeblow wrote:

Dirty wrote:

joeblow wrote:
lets see....in the pics it has one link either side....thats two....than there is one in the middle roughly( like a torque rod )...thats three.....plus the panhard rod....mmm...that makes for four as far as i can tell.

You don't include the panard bar in the link count.

- David.

umm.....i think you do............lets see.......a standard tojo or nissan front is a three link yes?....two control arms and panhard........that ='s three..not two.

Here is a quick read to break this all down.
http://www.automotivearticles.com/Suspe ... gn_2.shtml

And the set-up on the front of a patrol/cruiser/etc technically isn't a link design as the arms are rigid to the axle tube not pivoting. Someone might be able to come up with the correct technical term.

- David.

i have 1 question, how many links does the 5 link kit have on a patrol?

left uppper & lower = 2
right uppper & lower = 2
panhard rod = 1

total 5?

or am i missing something?

atari4x4 wrote:i have 1 question, how many links does the 5 link kit have on a patrol?

left uppper & lower = 2
right uppper & lower = 2
panhard rod = 1

total 5?

or am i missing something?

Technically that is a 4-link, as it is still a four-link if you replaced the panard with a Watts link (not a 6-link in this case).

But if you where talking about a "5-Link" most people know what you mean. We are talking about technical names vs common names here.

- David.

I think i'll stick to the common names (not just here) used by everyone, including manufacturers.

The 'technical' names in that link don't do it for me. How is a panhard (or Watt's link) not a locating link in a suspension system? It laterally locates the axle. Two lowers, two uppers and a panhard is 5 locating points in the suspension system.

It might be technically incorrect, but I think I'll stick with it lol.

It's called a 3 link + Panhard

Panhard rods are counted as links. They call this a 3 link + panhard to distinguish it from the 4 link with no panhard rod (ie 4 links locating the axle, often triangulated). A 5 link has four links locating the axle and a panhard rod.

Now that that's been cleared up. Lets help the OP with his question.

This thread is a great read for understanding link suspension. It will explain how changing separation, triangulation etc affects roll axis and the like.

Pirate4x4.com: Link Suspension for Dummies

I agree with Dirty. If you are going to 3 link it, piss off the radius arms and use proper links.

Hekta wrote:It's called a 3 link + Panhard

Panhard rods are counted as links. They call this a 3 link + panhard to distinguish it from the 4 link with no panhard rod (ie 4 links locating the axle, often triangulated)

Now that that's been cleared up. Lets help the OP with his question.

Exactly!

The other front arrangements on stock coil sprung patrols cruisers and rovers are called radius arms plus panhard.

The rear suspension on coil sprung patrols and cruisers, and the above mentioned 4 link plus panhard are 4 link plus panhard.

The panhard is a link. Radius arms are not links, nor are A frames (as used on rear of many coil sprung rovers.

Technically in kinematics (which is what we are discussing), a link is a member that can only carry load along it's longitudinal axis.

A free body has 6 degrees of freedom - translation in 3 axii (x,y,z) and rotation about those 3 axii.

The suspension links we are talking about , have to prevent only 4 of those degrees of freedom, and allow 2 only - vertical translation and rotation about the fore and aft horizontal axis. So 4 links are the minimum required to prevent 4 degrees of freedom.

If you have 4 links plus panhard, it will resist 5 degrees - but because of flex in the bushes used at the ends of the links it does not do offer 100% resistance.

If you had 3 links and no panhard, you would only prevent 3 degrees of freedom and the axle housing would be able to move from side to side.

You can make the radial arm setup flex quite nicely.

Alot of people dont fix the common causes of limited flex.

The biggest cause of the limited flex in a radial 3link setup is the diff brackets themselves. They are so close to the radial arm that they bushes only allow a few mm of flex b4 the arm hits the inside of the bracket.

If you space the brackets out 1" each side of the arm and use spacers with ID of the bolt and OD of the inner bush sleeve to keep it centered the arm will be able to twist in the bushes and give a great deal more flex.

This design is used in some after market leaf spring setups where the shackle is spaced off the spring to allow the spring to rotate in the bush without binding on the insides of the shackle.

Its a very simple and effective mod... i don't know why more people are not doing it..

Z()LTAN wrote:You can make the radial arm setup flex quite nicely.

Alot of people dont fix the common causes of limited flex.

The biggest cause of the limited flex in a radial 3link setup is the diff brackets themselves. They are so close to the radial arm that they bushes only allow a few mm of flex b4 the arm hits the inside of the bracket.

If you space the brackets out 1" each side of the arm and use spacers with ID of the bolt and OD of the inner bush sleeve to keep it centered the arm will be able to twist in the bushes and give a great deal more flex.

This design is used in some after market leaf spring setups where the shackle is spaced off the spring to allow the spring to rotate in the bush without binding on the insides of the shackle.

Its a very simple and effective mod... i don't know why more people are not doing it..

i would tend to disagree. flex it up with no front bolts and you can see the front bush misalign downwards on droop and upwards on compression. it's the bolts trying to pull themselves out of the arms vertically that limits travel

yes thats right, but it all goes to helping it flex.

Taking the front bolts out defeats the purpose of the radial arms. With the bolts removed its like a 2link almost lol

if you take the front bolts out and the top link off what stops the diff from rotating??? if only two bolts in the back holes you have a pivot point for the diff to rotate do you not??? i think you would need at least three bolts from arm to diff housing other wise nissan and toyota could save millions of dallors by using less bolts


when is a link not link???

jkv6 wrote:if you take the front bolts out and the top link off what stops the diff from rotating??? if only two bolts in the back holes you have a pivot point for the diff to rotate do you not??? i think you would need at least three bolts from arm to diff housing other wise nissan and toyota could save millions of dallors by using less bolts


when is a link not link???

You only take the front bolt out of one side, not both.

Layto....

lay80n wrote:

jkv6 wrote:if you take the front bolts out and the top link off what stops the diff from rotating??? if only two bolts in the back holes you have a pivot point for the diff to rotate do you not??? i think you would need at least three bolts from arm to diff housing other wise nissan and toyota could save millions of dallors by using less bolts


when is a link not link???

You only take the front bolt out of one side, not both.

Layto....

you take the front bolts out of both sides, but there is an upper link to controld torque.

To those who think that i should just cut off the front of the leading arms or even the front mounting holes, what happens if it turns out to be a dismal failure? I can hardly just go and weld a bunch of front mounts back on and buy whole new arms can i? Well i can but it would be a PITA and expensive.

rockcrawler31 wrote:

lay80n wrote:

jkv6 wrote:if you take the front bolts out and the top link off what stops the diff from rotating??? if only two bolts in the back holes you have a pivot point for the diff to rotate do you not??? i think you would need at least three bolts from arm to diff housing other wise nissan and toyota could save millions of dallors by using less bolts


when is a link not link???

You only take the front bolt out of one side, not both.

Layto....

you take the front bolts out of both sides, but there is an upper link to controld torque.

To those who think that i should just cut off the front of the leading arms or even the front mounting holes, what happens if it turns out to be a dismal failure? I can hardly just go and weld a bunch of front mounts back on and buy whole new arms can i? Well i can but it would be a PITA and expensive.

Ah, i though you were refering to just pulling a front bolt on a standard radius arm front end to get more flex. My bad

Layto....

i think i miss read what your are up to the third link only goes in when the bolts come out?? i read as third link comes off when bolts come out


Basically i was going to keep the arms, and put in a removable top third link


If i put in the third top link, do you think it would bind or work against the other arms if i just left in all the time on the road? I don't mind putting it in and out when i want to go for a wheel, it's only a couple of minutes but it would be one less thing to worry about if it can stay in

sorry do not know to use quote thingy

While I can't say I've tried it, in principle if you left the top link in all the time it would cause it to bind up big time wouldn't it? Unless the arc it travelled in was complimentary to that of the radius arms and their effect on pinion angle throughout travel?

With the upper link in and 2 radius arm bolts removed it would behave the same as a normal 3link+panhard as long as the radius arms had room to move within their diff bracketry/mounts?

Could useful (or worthwhile) geometry be attained based on using the arms as lower links?