[tanshi]

Do many people have much in the way of experiance with the rangie rear a-arm suspension setup? In its stock form how good was it. Travel etc?

will it work equally well on the front of a vehicle?

What sort of alterations could you / should you make to it to improve it? Longer arms?. changing the chassis end from pins to other types? etc?

if your fitting it to non rangie diffs can you just move the lower arms in the same distance both ends so you can mount them on narrower diffs with out adversly effecting how they work. etc?

is there a better option? basically i wouldnt have the first clue about designing a good working 3 link / 4 link etc. fromt what i can tell the rangie a arm is one of the best out of the box configs and a good place to start / learn about coils. comments and suggestions welcome

[royce]

get the 4 link calculator and start messing, the only think the rangie stuff gives you is not having to worry about fabbing stuff, you still have to get the geometry right

[tanshi]

got the calculator

as i said i know very little about it. I understand the terminology to a degree.

but getting the "right" amount of anti-squat, roll centre and all the other miriad of settings is insane

[royce]

Measure a rangie and stick the values in and see what happens

get onto outers and have a real good look at all the stuff Rhett has built over the years, he spends so much time testing and mucking around and trying different stuff its amazing

[Highway-Star]

Well hopefully I should have some rangie arms tomorrow or wednesday, so I can take some measurements, and see where that leaves us. I still have not had a look at the 4 link calculator, but I've read some of my text book on an introduction to this.

[31zook]

This write up will explain in fair deatail on what and where anti squat and roll center should be...
http://www.muddtanks.com/4LinkSuspArticle.htm

[kreecha]

One thing to note when using the 4-link calculator and setting up the 3-link a-arm suspension is to ensure the "Upper Links, Axle End, Y-coordinate"
is the conversion point of the A-arm, generally this will be about a 0-value.

I did mine like this with a trailer hub, and stub axle design.











hope this helps.

[Fatzook]

like this? standard arm and ball joint.

[Gwagensteve]

There's nothing wrong with the Rangie A arm.... however, It's a terrible idea for the front. You'll have quite bad bumpsteer - at least as bad as a leaf spring sierra - with an A Arm in the front.

There's also nothing wrong with rangie radius arms (front) and that's what I'm setting up in the back of my LWB right now, and with the panhard rod in the right spot, you'll have better than stock bumpsteer.

Steve.

[tanshi]

yours were stock arms pete?

im not overly worried about bump steep. specially as i drive a leaf sprung sierra now and it will not be a road going car at all.

[kreecha]

Gwagensteve wrote:

There's also nothing wrong with rangie radius arms (front) and that's what I'm setting up in the back of my LWB right now, and with the panhard rod in the right spot, you'll have better than stock bumpsteer.

Steve.

Steve,
I too contemplated putting radius arms in the back of my cruiser.
Are you aware that this can create bad squat characteristics?

[kreecha]

Fatzook wrote:

like this? standard arm and ball joint.

nice.

[tanshi]

its a pity this thing flexed like a vit on the front

[joeblow]

Gwagensteve wrote:

There's nothing wrong with the Rangie A arm.... however, It's a terrible idea for the front. You'll have quite bad bumpsteer - at least as bad as a leaf spring sierra - with an A Arm in the front.

Steve.

doing an a-arm in the front that does not have any bumpsteer is possible, but the math and angles of everything has to be spot on. ask anyone who has driven my vehicle.........NO bumpsteer.

[Fatzook]

tanshi wrote:

yours were stock arms pete?

im not overly worried about bump steep. specially as i drive a leaf sprung sierra now and it will not be a road going car at all.

No the trailing arms were extended. They were about 1100 long if I recall.

[Fatzook]

tanshi wrote:

its a pity this thing flexed like a vit on the front

Thats called ' Stability'

[tanshi]

I dont suppose you would post your figures as an example joe?

[tanshi]

suurree pete

[Taff]

kreecha wrote:

One thing to note when using the 4-link calculator and setting up the 3-link a-arm suspension is to ensure the "Upper Links, Axle End, Y-coordinate"
is the conversion point of the A-arm, generally this will be about a 0-value.

I did mine like this with a trailer hub, and stub axle design.



hope this helps.

What exactly are you building? 6x6 something?

[Gwagensteve]

joeblow wrote:

doing an a-arm in the front that does not have any bumpsteer is possible, but the math and angles of everything has to be spot on. ask anyone who has driven my vehicle.........NO bumpsteer.

You are hurting your credibility by claiming your car as NO bumpsteer. A car with a conventional drag link and an A frame has bumpsteer. It's impossible to engineer out because a drag link "shortens up" from left to right as the suspension cycles but the A arm doesn't permit the axle to move from left to right in phase with the drag link, unlike a panhard rod. That equals bumpsteer. Primary school geometry will prove this.

What you have is very limited bump steer due to a flat draglink angle. That's great, and will give very good behaviour at ride height, but that doesn't mean your suspension doesn't have bumpsteer, it just means you don't have concerning bumpsteer, or significant bumpsteer, or significant bumpsteer in the suspension'd normal working range. That's not the same thing as NO bumpsteer.

A stock sierra doesn't have significant bumpsteer either. It's suspension lift that makes the bumpsteer bad in leaf sprung cars, or, more specifically, vertical separation between the tie rod and pitman arm.

Of course, stock coil sierra has almost no bumpsteer, because it has a panhard rod in phase with the drag link.

Steve.

[joeblow]

Gwagensteve wrote:

joeblow wrote:

doing an a-arm in the front that does not have any bumpsteer is possible, but the math and angles of everything has to be spot on. ask anyone who has driven my vehicle.........NO bumpsteer.

You are hurting your credibility by claiming your car as NO bumpsteer. A car with a conventional drag link and an A frame has bumpsteer. It's impossible to engineer out because a drag link "shortens up" from left to right as the suspension cycles but the A arm doesn't permit the axle to move from left to right in phase with the drag link, unlike a panhard rod. That equals bumpsteer. Primary school geometry will prove this.

What you have is very limited bump steer due to a flat draglink angle. That's great, and will give very good behaviour at ride height, but that doesn't mean your suspension doesn't have bumpsteer, it just means you don't have concerning bumpsteer, or significant bumpsteer, or significant bumpsteer in the suspension'd normal working range. That's not the same thing as NO bumpsteer.

Steve.

you can engineer the arm to move in another direction to counteract compression......................................but i do appologise as you must have tried a setup like this and are speaking from experiance..........

[Gwagensteve]

How about droop then?

I assume you're offsetting the arm slightly to make it swing the axle in the same direction as the drag link is trying to pull it. under compression. That's a compromise, but in total, you'll still have the same bumpsteer though the whole range of suspension travel as a leaf spring car though - it's just swings and roundabouts because under droop, with a flat drag link angle. you';; have twice the bumpsteer under droop you'd have with a vertical axle path.


Steve.

[kreecha]

Taff wrote:

kreecha wrote:

One thing to note when using the 4-link calculator and setting up the 3-link a-arm suspension is to ensure the "Upper Links, Axle End, Y-coordinate"
is the conversion point of the A-arm, generally this will be about a 0-value.

I did mine like this with a trailer hub, and stub axle design.



hope this helps.

What exactly are you building? 6x6 something?

yeah mate 6x6 cruiser, but I twisted the chassis, so now I am on the hunt for a LWB Zook.

[31zook]

i love how joeblow manages to get his entire point across in one sentence...

6x6 wow thats pretty cool

[joeblow]

tanshi wrote:

I dont suppose you would post your figures as an example joe?

when i'm well enough to fit the entire new front end components i will post some pics of how the drag link moves to counteract the diff cycle with the a-arm.

[Highway-Star]

joeblow wrote:

tanshi wrote:

I dont suppose you would post your figures as an example joe?

when i'm well enough to fit the entire new front end components i will post some pics of how the drag link moves to counteract the diff cycle with the a-arm.

That will be most appreciated

[kreecha]

31zook wrote:

6x6 wow thats pretty cool

A painful labour of love