Linked rear help

[justinshere]

Hey

I know this topic gets posted every week but mine a little different.

Im trying to decided what link rear i should run.
Got a lux, using the big rear GU diff leaf sprung one.
I want to get enough movement out of it to get full use of 18" coilovers.

Im was leaning towards a 4 link but ive now been thinking of a nissan 5 link rear but with the arms about 40% longer. I used to have a GQ and the rear didnt flex to bad with standard arms.
Anyone tried longer arms? and got thoughts?

Lengthened 5 link Vs Tri. 4 Link, what do u think?

Thanks

[Nelso]

Option 3: 3 link + panhard

[cooter]

i would say triangulated 4 link but only cause mine works well we used rover rear uperlinks in my mates gq diffed lux flexes awsome

[justinshere]

Option 3: 3 link + panhard

Yeah thought of that but i didnt know how friendly it would be if i gets driven on the road.

[justinshere]

i would say triangulated 4 link but only cause mine works well we used rover rear uperlinks in my mates gq diffed lux flexes awsome

So u 4 linked the lux to?
Got any pics of it?

[90Mav]

just wondering why you would want a H260 diff? i am thinking of replacing mine (in a gq ute) with the h233 as the 260 seems too big and hangs up all the time.

[locktup4x4]

Dual or single triangulated 4 link for the rear. These are 16" air shocks. I built this dual triangulated 4 link last year.

18" coil overs are really long. There aren't as many spring combos for the 18" as there are for the 16" and shorter.

Jason

BEFORE


AFTER

[-Richo-]

Not sure why your even considering a 5 link, triangulated 4 link is the way to go.

Im also at a loss to why people always think 3 links are terrible on road, my old lux had a 3 link front and would happily do highway speeds without any issues whatsoever, it still does as far as i know...

[justinshere]

just wondering why you would want a H260 diff? i am thinking of replacing mine (in a gq ute) with the h233 as the 260 seems too big and hangs up all the time.

It was cheap enough and strong. Wanted the floaters and its being converted to discs and getting the bottom of it shaved for clearance.

[justinshere]

Dual or single triangulated 4 link for the rear. These are 16" air shocks. I built this dual triangulated 4 link last year.

18" coil overs are really long. There aren't as many spring combos for the 18" as there are for the 16" and shorter.

Jason

Yeah they are long but i already had em so ill use them. Ive already got them setup with dual coils 100/200 i think ill have to soften em up abit cos they were originally for the front of a truck.
Cheers

[locktup4x4]

Dual or single triangulated 4 link for the rear. These are 16" air shocks. I built this dual triangulated 4 link last year.

18" coil overs are really long. There aren't as many spring combos for the 18" as there are for the 16" and shorter.

Jason

Yeah they are long but i already had em so ill use them. Ive already got them setup with dual coils 100/200 i think ill have to soften em up abit cos they were originally for the front of a truck.
Cheers

Any pictures of your build?

Jason

[justinshere]

Not sure why your even considering a 5 link, triangulated 4 link is the way to go.

Im also at a loss to why people always think 3 links are terrible on road, my old lux had a 3 link front and would happily do highway speeds without any issues whatsoever, it still does as far as i know...

Just trying to look at all options.

Im not speaking from experience with the 3 link topic but ive heard mixed opinions.
When it comes to 3 linking the rear do u always put the upper arm to the top of the pumpkin wether it be in the centre or offset?

So what the key to a good setup 3 link?
Bit of tri on the lower arms, keep the panhard flat as possible, and make sure theres a decent amount of seperation between the arms on the diff end?

[justinshere]

Any pictures of your build?

Jason

Yeah but its nothing major yet, getting the diff back in a week or two thats when decent progress will start!

[-Richo-]

Not sure why your even considering a 5 link, triangulated 4 link is the way to go.

Im also at a loss to why people always think 3 links are terrible on road, my old lux had a 3 link front and would happily do highway speeds without any issues whatsoever, it still does as far as i know...

Just trying to look at all options.

Im not speaking from experience with the 3 link topic but ive heard mixed opinions.
When it comes to 3 linking the rear do u always put the upper arm to the top of the pumpkin wether it be in the centre or offset?

So what the key to a good setup 3 link?
Bit of tri on the lower arms, keep the panhard flat as possible, and make sure theres a decent amount of seperation between the arms on the diff end?

The key to a good link setup, whether it be 3 or 4 is good link geometry, but what is desired for some may not be the same for others. I aim for 100% anti-squat, roll centre as close to the CoG as possible with minimal roll steer (+ or - 5 degrees is acceptable) as this is what works for me. You basically need to find what compromise suits you best between all the elements of a link setup.

Upper link can be mounted wherever on the diff, doesnt have to be on the pumpkin. Separation at the diff should be about 1/4 the diametre of your tyres, having said that though i have seen link setups with less separation that seem to work well. More separation means less stress (leverage) on the links, joints and mounts.

There is no need to triangulate with a 3 link as the panhard handles lateral location of the diff.

All that said, relocate your fuel tank and do a triangulated 4 link

[Gwagensteve]

locktup4x4 - this is not a criticism, your car is cool, but more an observation.

in the two photos you have posted, you have gained about 6" of articulation (good) but easily all of that 6" has been turned into extra angle on the body, and from what I can see, the front end isn't compressing as hard as it was with the leaves in the rear.

I've seen this in a number of link converted car with leaf front ends- the rear ends up with heaps less roll stiffness than the front and the car gets "floppy" on steep climbs. It might not be a problem where you are, but here where we are, I have found concentrating on getting the front to work deep into it's travel and harder tan the rear - low and with lots of droop travel- makes for a more predictable car under power.

Just some thoughts.


Steve.

[locktup4x4]

Yes he's was running a heavy set of leafs up front. I did that last year and if I remember correctly we had around 250psi in the shocks to start with. No tuning. He has also chained his rear end down since. He was dropping it onto its side allot while tuning it in. He's going coil overs in the front now. This linked back end did allot more work then his heavy front leafs. He's also on a budget. One end at a time.

Jason

[1MadEngineer]

locktup4x4 - this is not a criticism, your car is cool, but more an observation.

in the two photos you have posted, you have gained about 6" of articulation (good) but easily all of that 6" has been turned into extra angle on the body, and from what I can see, the front end isn't compressing as hard as it was with the leaves in the rear.

I've seen this in a number of link converted car with leaf front ends- the rear ends up with heaps less roll stiffness than the front and the car gets "floppy" on steep climbs. It might not be a problem where you are, but here where we are, I have found concentrating on getting the front to work deep into it's travel and harder tan the rear - low and with lots of droop travel- makes for a more predictable car under power.

Just some thoughts.


Steve.

steve, in most front engine vehicles it is preferable to have a 'stiffer' or more predictable front end. every few months dave and i have an itch and want to link the front end, but then we realise that there is not that much benefit over what we have. It is soooooo predictable and will out-climb nearly anything!!! (that terrible voice of reason seems to always save me a lot of work!!). having the stiffer front allows us to get the nose up and then just punch it!! and we know the rear will plant the tyres and follow.

http://www.offroadimages.com.au/4x4even ... fullsize=1

4 link rear - leaf front IMO. (never stopped us!!!)

[Gwagensteve]

A couple of observations about your set up though - your front end looks like its working quite well, but also, your rear end has lots of compression - on the ramp, the back edge of your cab looks to almost level with the axle tube at the rear.

Obviously you have created a setup with a very low COG in the rear for the amount of travel, and I am sure your car stays quite planted even with a front wheel well in the air. It also looks like at full travel in the rear the drooped coil has only just unloaded. I agree I reckon this setup will respond very well to powering up obstacles.

Compare that to the car posted by Jason, (again not having a go, just an example) and for about the same amount of overall articulation the cab is sitting way, way higher, and is laid over heaps more. This might be useful in big rocks but for our terrain that gets spooky.

My direct experience is with leaves and SWB cars where we run more roll stiffness in the rear than the front but the same rate and shock valving front and rear. for our recreational use, this keeps the front end on the ground for longer and prevents the cars from "flopping" as the rear end unloads - the body tends to follow the rear rather than the front, which limits body angle and therefore helps to fight the car unloading.

PErsonally, for a recreational car, I like to see as close to a 50/50 articulation split as possible. Horses for courses though, I can see that in comp use a stiffer front end may have its advantages. (also when dropping off)

Steve.

[locktup4x4]

If I were to do mine over. I would stay with the leaf spring front. Yes the 3 link front works great in the BIG rocks and is predictable. But it gets spooky on a steep side hills unless I suck it down with the winch. I am able to climb obstacles easier now then I was able to with the leafs. But after its all said and done it was allot of work and I was happy with the leafs. And it was more predictable. Now with the coil overs I need to bump up my rear spring rate. I get more body role. But I also like a soft rig. Go Figure.

Your not hurting my feeling with your observation.

Jason

[1MadEngineer]

sorry about the pic, i should have noted that it has the front and rear hydraulics pumped to the max!!
the front doesn't usually have quite that much flex (close though).

your right the rear does "Sit" quite a lot, which is perfect for this rig. As it has big advantages in comp situations where you are dropping down at full lock off ledges!!

[justinshere]

What about a 3 link rear using an A frame.
Pros n Cons?

[chunderlicious]

con, rear steer. pro, easy

[justinshere]

con, rear steer. pro, easy

yeah thats as far as i got too

[nastytroll]

I prefer the rear steer efect, it has benefets especialy in gullies with big rocks n crab holes.
In the patrol it also makes it drive better onroad if driven underpower. If you have a good amount of torque it will respond well out of corners with the trottle.
With the standard 5 link rear the patrols understeer into corners n oversteer out of them.
Horses for courses, if you know some people with different setups see if you can go for a drive in their trucks n see what feels good for you.

[professor]

What I have found with the motion of the 3-4 links panards A frames leaf springs although it is good to get the correct linkages and linkage geometry right, it is the balance bias front to back that plays the most part in stability on a 4x4. having the front and rear balanced for what weight is on the wheels is one of the most critical engineering choices you can make to keep your rig stable and also keeping travel in check can also play a big part in stability. You have heard the term flex is over rated well in part this is true. If you have great flex and no bias balance front to rear its worth nothing. to be able to drop a front wheel off a ledge and not roll over that wheel end to end is where flex and stability shine. if you follow the buggie setups you will see a fight for this balance. the balance of motor position seat position weight in wheels low cog's its all the same, trying to balance the rig to be predictable.

everyone gets cought up in the link debate and overlooks the rest.

Chad

[Gwagensteve]

What I have found with the motion of the 3-4 links panards A frames leaf springs although it is good to get the correct linkages and linkage geometry right, it is the balance bias front to back that plays the most part in stability on a 4x4. having the front and rear balanced for what weight is on the wheels is one of the most critical engineering choices you can make to keep your rig stable and also keeping travel in check can also play a big part in stability. You have heard the term flex is over rated well in part this is true. If you have great flex and no bias balance front to rear its worth nothing. to be able to drop a front wheel off a ledge and not roll over that wheel end to end is where flex and stability shine. if you follow the buggie setups you will see a fight for this balance. the balance of motor position seat position weight in wheels low cog's its all the same, trying to balance the rig to be predictable.

everyone gets cought up in the link debate and overlooks the rest.

Chad

X Eleventy gazillion gazillion Chad.

Steve.

[redzook]

con, rear steer. pro, easy

rear steer has nothing to do with an aframe

[justinshere]

con, rear steer. pro, easy

rear steer has nothing to do with an aframe

Dont just leave it at that... explain
Is it the tri. of the links???

[chunderlicious]

con, rear steer. pro, easy

rear steer has nothing to do with an aframe

i know but most people who do a frames on here do it on their patrols or just dont know to tri the lowers aswell. a frame is a bolt on mod now for patrols and with the lowers pointing out the the chassis and the a frame they steer pretty bad in the rear, they also get rolly.

[redzook]

con, rear steer. pro, easy

rear steer has nothing to do with an aframe

Dont just leave it at that... explain
Is it the tri. of the links???

yes the biggest determining factor in rear steer is the lower links

a 4 link and Aframe are pretty much identical