One link suspension setup without a panhard rod

[Lewis]

A sway bar is just the American term for an anti roll bar, so effectively those two slender links are the drop links/stabiliser links

[Bowie69]

I can not say what the middle, vertical link is.

The middle jointed link is the equivalent of DD's sliding a-frame above, just sat vertically rather than roughly horizontal.

[uninformed]

The middle jointed link is the equivalent of DD's sliding a-frame above, just sat vertically rather than roughly horizontal.

ok, you ll have to explain how it works. Im currently not seeing it. DD's sliding frame is his lateral location, correct? it has to slide due to the change in length as the one link goes through travel/articulation, correct? That vertical link looks like it can swing left to right?

[Bowie69]

No, I don't think it can; look further up, it is sliding inside a rigidly mounted tube welded to the chassis.

So yes it can pivot, but the position relative to the chassis shouldn't change in the horizontal.

[bill van snorkle]

No, I don't think it can; look further up, it is sliding inside a rigidly mounted tube welded to the chassis.

So yes it can pivot, but the position relative to the chassis shouldn't change in the horizontal.

Yes, you are correct Bowie. After enlarging the photo, I can see that it only pivots on the axle, and the gussets bracing the upper tube to the crossmember are visible. I think my LandRover at twice the weight of a Suzy would require something a bit more substantial though.

[Bowie69]

Yes, you are correct Bowie. After enlarging the photo, I can see that it only pivots on the axle, and the gussets bracing the upper tube to the crossmember are visible. I think my LandRover at twice the weight of a Suzy would require something a bit more substantial though.

Quite agree, but an interesting take on it nonetheless.

[bill van snorkle]

Quite agree, but an interesting take on it nonetheless.

As the axle moves up and down, it would move for and aft. I can't see, the way the upper tube is rigidly mounted, how the sliding rod would align itself with the axles variable position. Does the crossmember rotate?

I'll have another look

[Bowie69]

Does look like that is possible, it's on a tubular cross member behind the chassis crossmember, which could be able to rotate.

Aha, some more pics: http://www.zukikrawlers.com/showthread.php?p=541825

[bill van snorkle]

Does look like that is possible, it's on a tubular cross member behind the chassis crossmember, which could be able to rotate.

It appears that the heim/rose joint attaching the sliding rod to the axle housing can slide for/aft along the bolt within the mounting bracket.

[uninformed]

It appears that the heim/rose joint attaching the sliding rod to the axle housing can slide for/aft along the bolt within the mounting bracket.

so the vertical sliding rod does not move/swing for/aft, just that movement is allowed at the axle housing?

[dirtydiesel]

Now for my opinion lol your barking up the wrong tree.... this system as it extends creates huge anti-sqaut figures.... I feel this is bad for climbing especially with a short wheel base.... my thoughts are that you want to setup antisquat so as the suspension extends it decreases

In a climb as your nose goes up your CoG goes up compared to the rear suspension the links (or link lol) angle increases this places more weight vectored down the links this takes weight off the suspension at speed this means your wheels dont stay in contact as well (this doesnt mean much if you crawl up hills) competition wise this is big

as the suspension extends you compound the problem etc

this is why I built my back end the way I did

I dissagree,

The geometry of the links behaves identically to radius arms front and rear, like disco 2, mk2 pajero, TLC70 series, Gwagon..... these are all very stable on climbs

I really like the extra traction the increased anti-squat gives,

The biggest advantage of the one link is it's simplicity, it works well and it takes a lot of damage or wear to radiacally alter the geometry.

The sliding A frame just adds a jewel to its crown, because the axle doesn't walk under the car during articulation it doesn't push the car around, and the total absence of axle walk means the tyre takes up a lot less space throughout its suspension cycle which makes for easier packaging of other components.

I also believe the way i do mine by welding the link directly to the axle takes all the loading of the axle case, also there are no brackets or links compromising ground clearance.

[De Ranged]

Would you mind telling me what the rear AS % is..... I'm guessing that it will be around the 60% mark, from the look of it you have a low CoG and the rear link looks to be on a pretty flat angle lol a bit of a guess since the pic's are when flex'd

For the books 60% is where I aim with standard suspension builds.... the more lift the lower the number, longer wheel base=higher%, lower the CoG the higher the number, the more HP the lower the %.... I'm not saying this is the magic number lol its a number that works, with no nasty habbits

My truck is sitting on 86% from memory and I can take it to just over 100% AS at rest, to date it has only been out in the mud so I dont know if it works.... it surprised me in the mud, the back end kept pushing when I honestly expected it to loose traction, on multiple occasions, unfortunately due to the slippery conditions HP climbing was the only way and an old LD28 dont have much of that lol

As for anything hanging down lol I have better link clearance than you but that is just good packaging and is something a builder no matter what system they use, should be considering

I'm not saying radius arms don't work, (New Zealand #1 trials truck, 2 yrs ago was radius arms),or 1 links, I believe that there are better systems that is why Ive gone to the trouble of building mine.... am I the first to think this way no, I found a print of text from a book on suspension with the line "For offroad conditions a reverse rate anti squat will make for a more stable suspension" annoyingly I havent been able to find it again lol it has been the only thing I've found to do with reverse rate suspension

[bill van snorkle]

I also believe the way i do mine by welding the link directly to the axle takes all the loading of the axle case, also there are no brackets or links compromising ground clearance.

The bolt on One Links that attach to the radius arm brackets do compromise ground clearance a little over what could be achieved by welding the link directly to the axle.

My wishbone, attaching as it will to a 50mm 'dropper' off the radius arm 'rear' bracket only, doesn't reduce clearance.

Tying the wishbone to the pinion housing on a rubber pad to prevent rotation, provide some noise/vibration insulation, and permit experimentation with various castor angles, will hopefully work, without twisting the diff out of the banjo housing. If it does, it's back to the drawing board. Regardless, it's all part of the fun of experimentation.

[o_teunico]

Why was WildFing given a 3Link instead of reusing the wishbone from the 6x6? Now a difficult queastion to answer: wich of them is best?

[bill van snorkle]

Why was WildFing given a 3Link instead of reusing the wishbone from the 6x6? Now a difficult queastion to answer: wich of them is best?

When I built the 6x6 circa 1978, RangeRovers had just been released, most 4x4's had stiff inarticulate leaf spring suspension systems, and there was little awareness in the offroad fraternity of the benefits of good suspension articulation. The only vehicles back then that inspired me were Scammel Explorers and French Laffly 6x6's. The Scammel used a true One Link wishbone front suspension without Panhard, so I decided to go that way, but use cross linked airbags instead of the Scammel style transverse leaf spring, which also doubled as a Panhard rod.

20 odd years later when I began playing with WildFing, RangeRovers were finding their way into wrecking yards, so stuff like radius and trailing arms etc were available to me cheaply, so instead of re using the old 6x6 wishbone, I tried a radius arm front, which was a huge improvement on leaf springs but still lacked the articulation the 6x6 had spoilt me with. As we all know now,it is an easy step to change from RA's to 3 link. Cannot really say at this stage which is better. As you may know,I am building my One Link wishbone with the chassis end mounted 100mm or 50mm offcentre, so the result could be very beneficial,a complete f#$%&up,or somewhere in between.

[dirtydiesel]

Would you mind telling me what the rear AS % is..... I'm guessing that it will be around the 60% mark, from the look of it you have a low CoG and the rear link looks to be on a pretty flat angle lol a bit of a guess since the pic's are when flex'd

For the books 60% is where I aim with standard suspension builds.... the more lift the lower the number, longer wheel base=higher%, lower the CoG the higher the number, the more HP the lower the %.... I'm not saying this is the magic number lol its a number that works, with no nasty habbits

My truck is sitting on 86% from memory and I can take it to just over 100% AS at rest, to date it has only been out in the mud so I dont know if it works.... it surprised me in the mud, the back end kept pushing when I honestly expected it to loose traction, on multiple occasions, unfortunately due to the slippery conditions HP climbing was the only way and an old LD28 dont have much of that lol

As for anything hanging down lol I have better link clearance than you but that is just good packaging and is something a builder no matter what system they use, should be considering

I've calculated the rear AS@122% and the front AD@146%

[De Ranged]

Yay a day off .... where my head is in a good enough space that I can think lol blastard painkillers

Thank you for that.... I would never have guessed that high.... there is my guess at half that lol, I'm really starting to appreciate the gain in AS% with radius arm style suspension .... I only really considered them as something that came factory because they are cheap to make so were a good budget option for the makers and never considered them due to the limited flex

Hmmm and it climbs well... I could see the front end doing that pull down thing discussed in the AS% thread.... the back tho, this high a score should have it lifting some on acceleration with good grip, you don't happen to have any video of it in action

Now if this was a multi link suspension like say dual triangulated four link I'd expect this high a score to be moving the back end up on the flat, on rutted climbs where the wheels have to track to keep grip it would spin up at some point, and a steep good grip climb will try and lift the front wheels off (seen a dramatic example of the last one, a truck with a similar AS% climbing a very steep 4m high little gully... the rear lifted the front and the driver didnt back off, the back drove up under the front wheels causing the truck to peiete off the top and flip over backwards and hit the ground at the bottom on the front axle... bye bye front links steering etc lol

Hmmm just had an interesting thought, one of the odd standout things about radius arm suspension is the instant centre is at the chassis end of the link where it bolts to the chassis, with multi link this is closer to the opposite axle or past it.... this is something Ive never really paid too much attention too so long as it was within kuwi of the other axle..... now the instant centre is the pivot point where the arm that your links are, is pivoting

Dammit..... I can't quite join the dots on this in my head...... I think this could be why the radius arm style suspension works..... for every force you have a counter force.... my thought is the radius arm instant centre is there at the chassis mount, so is focused at that point.... but a multi link is focused further out at the other end of the truck or past it

Dammit the painkillers have started to work and I cant see how the effects work through....arghh lol sorry

[dirtydiesel]

The jimny buggy climbs really well, we're out next with it in 2 weeks so i'll see about doing a vid. From memory the rear pulls down under acceleration when there's traction.

I have been putting too much thought into this recently De Ranged, as i want to build my new buggy around the suspension and any tweeks i build in now willl be sealed in,

I am torn between building equal length links or having a longer rear than front to trade the rear AS against front AD?

[De Ranged]

Based off the idea on the AS% thread that high AD% causes a downward force on the front end under acceleration...I dont know if I agree with it as just a result of high AD%, but I think that you could get this effect with a radius arm style of suspension by the nature of the links being attached to the axle housing so it transfers the torque into the housing

The reason I dont agree with this being just a measure of AD% is the instant centre... the pivot point the links pivot on now if this was just a case of high AD% then this would be the point that the force would pull the body down, now in the case of a multi link suspension that would mean your pulling force is at the back end, or beyond

Something else to think about is this force is torque reacting on a lever, the link.... the longer the link the more the force is going to dissipate before it can pull down the body.... the reverse of using a bar on a wrench

Radius arm style had the instant centre at the chassis mount, very short

All of the above being correct then I would look at a shorter front end to make more of this

Now there is a catch since your links come to the same point (front, rear) and your radius arm style rear your AS% will be pushing up at the same point lol ..... I had never thought of this till now, I wonder how this would effect my link rear end lol too late for this thought tonight

[bill van snorkle]

Based off the idea on the AS% thread that high AD% causes a downward force on the front end under acceleration...I dont know if I agree with it as just a result of high AD%, but I think that you could get this effect with a radius arm style of suspension by the nature of the links being attached to the axle housing so it transfers the torque into the housing

The reason I dont agree with this being just a measure of AD% is the instant centre... the pivot point the links pivot on now if this was just a case of high AD% then this would be the point that the force would pull the body down, now in the case of a multi link suspension that would mean your pulling force is at the back end, or beyond

Something else to think about is this force is torque reacting on a lever, the link.... the longer the link the more the force is going to dissipate before it can pull down the body.... the reverse of using a bar on a wrench

Radius arm style had the instant centre at the chassis mount, very short

All of the above being correct then I would look at a shorter front end to make more of this

Now there is a catch since your links come to the same point (front, rear) and your radius arm style rear your AS% will be pushing up at the same point lol ..... I had never thought of this till now, I wonder how this would effect my link rear end lol too late for this thought tonight

I have posed the following question previously on other forum discussions without receiving an answer.

If the front radius arms chassis attachments happen to be behind the vehicles for/aft centre of gravity, do anti dive forces due to braking tend to lift both front and rear ends, instead of just the front? And conversely if the rear radius arm chassis attachments are in front of the for/aft COG, do antisquat forces tend to lift the whole chassis on steep climbs instead of just jacking the back end ?

Providing traction was maintained on both front and rear axles, I'd assume these opposing forces would counter each other to a degree. But what happens on a steep gradient when front end traction is marginal and rear end traction is high? The rear RA's lifting the whole chassis would presumably be lifting the COG, leading to a possible rear endover flip.

It would be a little more difficult to arrange radius arms or One Links etc in this way on a vehicle with a longish wheelbase, but on something like a Suzuki or even a SWB LandRover, one could get close.

[De Ranged]

If the front radius arms chassis attachments happen to be behind the vehicles for/aft centre of gravity, do anti dive forces due to braking tend to lift both front and rear ends, instead of just the front?

No.... your forgetting about the inertial weight transfer when you brake, so if your front links were behind the CoG then under brakes this moves further forward due to inertia this will load up the front springs and the links will lift the back of the truck

And conversely if the rear radius arm chassis attachments are in front of the for/aft COG, do antisquat forces tend to lift the whole chassis on steep climbs instead of just jacking the back end ?

Providing traction was maintained on both front and rear axles, I'd assume these opposing forces would counter each other to a degree. But what happens on a steep gradient when front end traction is marginal and rear end traction is high? The rear RA's lifting the whole chassis would presumably be lifting the COG, leading to a possible rear endover flip.

Yes but I see a couple of things here that muddy the waters lol

First you have a long (very long link to get infront of CoG) longer links dont ramp the rate of AS% as much as they extend... Now this is where Im guessing, I just havent found any books or anybody who can state this but I reckon the bounce you get (hopping) is due to this ramping rate

as you get torque the axle screws its self under the truck extending the links AS% increases due to extra angle, this continues till you either run out of travel or grip.... this removes the torque holding the axle there on extended suspension, gravity pulles the back down again.... tyres can get grip again away we go again...... this bouncing is what tips trucks over

The other thing is as you tilt up more and more weight goes onto the rear links less on the springs.... think of it like a vector (probably using this term the wrong way again lol) if the spring is one side of the vector the link is the other... now as you tilt truck the weight moves onto the link from the spring your back will move out, due to the spring pushing it out

Bugger lol I had a thought I was going to post up about link length, but..... arghhh I really hate this, buggered if I know why people become junkies this is so frustrating I just can't hold thoughts in my head or follow them through lol

[dirtydiesel]

Here's a couple of clips from today,

A little scale for that first hill climb

[discomikey]

biggin quarry?

[Lewis]

It seems to go well, have you turbo'd it now?

It looks like it climbs well and the rear suspension certainly seems supple and allows flex, however to be honest I'm so out of touch I can't really see what difference the sliding a frame makes to climbing ability over a panhard

Aggressive driving too, yourself or someone else?

[Anderzander]

I'll have to find a laptop - these videos won't play on my phone or tablet..... :-/