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Discussion Starter #1
After talking to a few different suspension places, im a little confused. To run a 4 inch lift do I need an adjustable upper arm, or a longer lower arm (disregarding the fact that the stock lower arm is weak).

Basically one suspension place told me that when lifting the Patrol, the rear diff will be pushed forward, and hence a longer lower arm will correct this problem, ANDD that the rear tyre will NOT be moved closer to the rear guard when comparing to stock.

Another place told me that increasing the lower arm will push the tyre to far back and cause it to scrub on the guard. So in order to fix the rear diff problem, id need to go a longer (adjustable) upper arm.

Car is a GQ, tyres are 35x12.5. No rear quarter chop at the moment, but it is on the cards.

So which is it ? Do need a longer upper arm, or a longer lower arm or both ?
 

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It really is a bag of worms, personal preference and vehicle have a fair bit to do with it.

Heavy Duty longer lower arms are the quickest, easiest, price conscious fix to get the pinion angle back within tolerance,

Adj Arms gives you the flexibility to get it spot on or more one way or the other depending on your setup.
Bigger tyres like 37's need to go back a bit further and will need some trimming, so using adj arms gets them in the right spot is preferred.

SWB Patrols with big lift will generally need both, as the tolerances are smaller due to drive shaft length.

If you lift it 4" of spring, then the rear diff will roll forward towards the center of the car, 16mm arms will push the diff back not quite 16mm, locating the diff into the factory position in the guard, keeping the tyre centered. Height also changes the roll of the diff, things like spring perches ect,

Short answer is 35's and a 4" lift will be fine with 16mm longer lower arms.

Hope it helps.
Cheers
 

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See i reckon that replacing the lower trailing arms with longer ones IS Mathematically WRONG. IMHO

Here is the logic, you should be able to make your own decision.

What is the purpose of the change??

When you lift a Patrol 4" the rear diff moves forward as the diff goes down in the radius of the travel controlled by the Lower Trailing Arm. So what has altered? Hmmm? Nothing!

Yes the Pinion angle has changed and should be addressed but technically the vehicle is just sitting in a state of Droop off standard suspension setup? Everything has gone down from the chassis by 4 inches but all stays in factory spec position.

The perceived problem is this.

You stand there and look at your car and the rear tyres look too far forward and the thing looks funny right? But that is just an Optical Problem, it looks funny. But its in the right spot. Now stand there and imagine that the car is at Max articulation and the suspension is under maximum compression? The lower standard length trailing arms will place the wheel, via the arc radius, in the EXACT place that it should be in the CENTRE of the guard, as per factory design.

Now standing there looking at the car. If you think that the real problem is that the car looks funny and you need to move the diff back so it looks good to YOU when sitting still. hmmm. OK add 16mm so it looks right, now imagine the full compression again? what happens now? the whole geometry of the suspension is OUT BY 16mm. The rear diff is now 16mm further back than its should be when it is sitting up in the guard in full travel and the back of your tyres are ripping the s h i t out of the back of your guards cause you moved the diff back

The actual problem is that as everything has drooped down when you lifted it you have altered the pinion angle of the rear drive shaft and diff. Because the diff is attached to the car by the trailing arms it has rolled forward as you lifted too and there is "Almost at design limit" of angle at the pinion now because the car is near designed max droop. You need to adjust that angle for sure to somewhere within tolerance.

Let the lower trailing arms (lower Control arms) Control how the rear diff is aligned to the car and the suspension for the full travel of the suspension up and down.

Let adjustable upper arms control how the rear diff is aligned to the drive train, the drive shaft. Adjustable uppers will let you roll the diff back slightly again to correct the pinion angle a little to within tolerance and also take some of the bend out of the rear springs as a bonus.

With this setup you car will be basically at standard Factory geometry specs and that cant be bad.

My 2c, Hope it helps mate.
 

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Let adjustable upper arms control how the rear diff is aligned to the drive train, the drive shaft. Adjustable uppers will let you roll the diff back slightly again to correct the pinion angle a little to within tolerance and also take some of the bend out of the rear springs as a bonus.
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The problem with this statement is you need to shorten the upper arms to take the bow out of the springs & you are rolling the diff forward same as fitting longer lower arms.
Shorter uppers or longer lowers is effectively the same thing as pinion angles go.
The main object is to take the bow out of the coils as coils are not designed to be bent
With longer lowers you also get stronger lower arms.
The only drawback with longer lowers is if you run super big tyres on a GQ the can rub on the rear mudflap area.
Each to his own. But i will always recommend longer lowers first.
Ideally iiif you could afford the cost is to use both 15mm longer lower arms & adjustable uppers & then the diff is close to factory specifications & the coils will be straight.
Think about it.
Cheers
 

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my 33s almost hit the back of the rear guard. so if i had 35s and longer lower arms well i may as well leave her in the shed cause i wont be going anywhere soon as that wheel starts to come into compression of the spring.
how close are your 35s now to rubbing the back guards. id imagine pretty close as a 35 only just fits inside a gq guard as it is. now imagine that 16mm further back. its almost inside the car.
imho go udjustable uppers and just heavy duty standard lowers and all shall be sweet.
 

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i went fixed lower and adj upper and i managed to get the pinion angle pretty much spot on.

cheers

phil
 

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ADVICE:
If you have a Ute or a Wagon that you are willing to cut guards then fit longer lower trailing arms.
If you have a Wagon that you don't want to cut the guards get upper adjustable trailing arms and also std length lower trailing arms. You can sometimes tweak the lowers to be a bit longer but check your clearances when at full compression.

For the die hard technically correct gurus who ask what is technically correct. I say to you, leave it at stock height, however the shorter upper arms effects the vehicle less then longer lowers. If you fit drop boxes to the rear lower trailing arms at the chassis then you are getting closer to correcting geometry in the rear.

TAIL SHAFT:
If you fit longer lowers then your tail shaft will pull apart a bit more. This however is not a problem. The uppers have a very minor influence on the tailshaft.

WHEEL BASE:
As you lift it, the wheel base will get a bit shorter at ride height however when the wheels are compressed into the guard then your wheel base will then be exactly the same as stock. Fix your wheelbase, stuff your guards, pull apart your tail shaft a bit.

LOWER ADJUSTABLE TRAILING ARMS: Don't do it unless you absolutely have to. They bend much easier because the solid thread bends.

I hope this clears things up.
Cheers
 

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ADVICE:
If you have a Ute or a Wagon that you are willing to cut guards ---- ON A UTE ????

You can sometimes tweak the lowers to be a bit longer---- MAYBE 15MM ????

If you fit drop boxes to the rear lower trailing arms at the chassis --- WTF ????

You fit longer lowers then your tail shaft will pull apart a bit more.This however is not a problem.- CORRECT

I hope this clears things up.-- NOT REALLY
Cheers
 

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i have 4 inch lift with snake racing adjustable lowers and factory uppers on a gq ute, no problems whatsoever with the setup pushes diff back to factory position can also line axle up properly and factory lowers get damaged easily, if your on a budget can save 300+ by doing lowers only. at full flex with 6 inch shocks my tail shaft doesnt slip off the spline has about 20mm before it does. heard the thread bends on the adjustable lowers but its solid metal too and even though its the weakest point in the arms haven.t had a problem and had mine for 2 yrs and im not gentle on them have dings and scratches on underside of the arms and no bends yet.

*maybe if i had enough money i would have went with rear lower drop boxes :p would give more clearance too

Cheers
 

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Eric the Vigilante
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Think outside the box Zordo, every piece of advice you're questioning makes sense.

"A ute... or a wagon you are willing to cut guards."

"You can sometimes tweak the lowers to be a bit longer" 15mm is still movement/tweakage

and drop boxes on trailing arms are not exactly unheard of, though they aren't a mass produced bolt on item, they wouldn't be too hard to manufacture.
 

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heres some pics of my wagon with shorter upper arms.. the diff was pulled forward a bit and the pinion angle has been corrected. but there is a tinnny bend in the springs. i think if i wouldve got longer lower arms i wouldve run into troubles with tyre rubbing the guard. however if i got a ute i would definatly just get longer lower arms for the extra strength.. but my lower arms were already braced when i got it... :D

CIMG41271.jpg
upper arms
CIMG41301.jpg
CIMG41321.jpg
lower arms
CIMG41311.jpg
 

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Zordo,

1. You questioned my statement, "If you have a Ute or a Wagon that you are willing to cut guards then fit longer lower trailing arms." Bananaman answered this for me but to clarify this a bit further for others. If you are not willing to remove mud flaps and guards on a wagon then please measure before you request +15mm lowers - I will talk more about this below.

2. I made the statement that for a GQ wagon you can sometimes tweak the lowers a bit longer. In my experience, unless you are willing to chop stuff or at the very least, get rid of your mud flaps, you nearly never get away with +15mm lower trailing arms on a wagon that has 33" tyres. +5mm and maybe +10mm but not +15mm. If you don't believe me, give Superior Engineering a call, they explained this to me years ago and it has served me well in the 1000s of kits that I have set up for people. I often ask the customer to flex it up until the tyre is fully compressed into the guard and measure the clearance to your mud flap. Often people already have no clearance so going any longer in lower trailing arms is going to cause problems. It is also interesting to note that not all Patrols came out with the same length lower trailing arms. Yes generally GU's are 10mm longer then GQ's but there are differences from time to time. When ordering lower trailing arms it is always best to measure yours then ask for how much longer you want.

3. The bit about the drop boxes on your lower trailing arms. I will quote myself so we can read my whole statement so you can get it, but I will highlight some words so when you read it again you should understand me better. I apologise, I should have added that this isn't a modification that we offer.
QUOTE OF MYSELF:
"For the DIE HARD TECHNICALLY CORRECT GURUS who ask what is TECHNICALLY CORRECT. I say to you, leave it at stock height, however the shorter upper arms effects the vehicle less then longer lowers. If you fit drop boxes to the rear lower trailing arms at the chassis then you are GETTING CLOSER TO CORRECTING THE GEOMETRY in the rear." Hopefully this clears it up, but if not I will go on.
If you look at the above picture, you will notice the trailing arms on quite a severe angle. Whenever the tyre hits a bump and compresses upwards, the arm has to travel in an arc instead of just vertically up the coils and shocks. If you TECHNICALLY WANT TO CORRECT THE GEOMETRY you would need to level out your lower trailing arms. The way to fix this geometry problem best however is to fit a long arm kit moving your trailing arm mounts forward 300mm on the chassis. This also helps prevent rear steer.

On another note when tyring to correct geometry, it is best if you can level out your panhard rods and drag link. Before you phone me up, no I don't sell a bolt on kit for this. It would stop all that jerking when driving up gutters etc. Landrover got around this by fitting an A-Frame so they can ditch the panhard rod. You can also triangulate your links to achieve the same thing.

Cheers
Shane
 

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i have 4 inch lift with snake racing adjustable lowers and factory uppers on a gq ute, no problems whatsoever with the setup pushes diff back to factory position can also line axle up properly and factory lowers get damaged easily, if your on a budget can save 300+ by doing lowers only. at full flex with 6 inch shocks my tail shaft doesnt slip off the spline has about 20mm before it does. heard the thread bends on the adjustable lowers but its solid metal too and even though its the weakest point in the arms haven.t had a problem and had mine for 2 yrs and im not gentle on them have dings and scratches on underside of the arms and no bends yet.

*maybe if i had enough money i would have went with rear lower drop boxes :p would give more clearance too

Cheers
I agree, for a Ute, longer lowers really is the best option unless you have worn upper bushes already.

About lower adjustable arms. I am sure 95% of the time, most will never have a problem however some years ago, I posted on the Outerlimits forum suggesting that the Snake adjustable arms are strong and won't bend, I was immediately shot down by examples of this happening. I am not bagging the Snake product here. They make it as strong as they can, Superior has the same problem with their adjustable lower trailing arms. If I had a set on my vehicle I wouldn't worry too much though, I just wouldn't be recommending it as THE BEST option.

Shane
 

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hey shane, agree with you on the idea of not best option and alot of the time flaming products is from a bad experience or just because others stand by a particular product i find these arms great not had a problem yet others may not but like you said if its an issue keep it stock and you wont have to worry about it at all
 

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Part of the furniture
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DAYMNNN battle of the suspension guru's!


from reading this,
im a happy to sit in the back of Zoro's buses anydays :)

just my opinion anyways.
 

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wow what a thread! this has helped me alot in sorting out my rear end for my gq for when i put 3" looks like adjustable lower and upper control arms! that should sort out both issues!

cheers finchy
 

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Except the adjustable lowers won't be as strong as the non adjustable type. I tried heading down this path but unless someone starts making the thread out of 4140 chrome molly then it can't be as strong. Of course they would cost a lot more. I am sure it wouldn't be cheap to thread it.

Shane
 

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DAYMNNN battle of the suspension guru's!


from reading this,
im a happy to sit in the back of Zoro's buses anydays :)

just my opinion anyways.
"Zoro" hey. :) I like your new nick name John.

At the end of the day +15mm lower trailing arms are going to work great in a Wagon as long as the customer is aware that they might need to trim guards or at the very least, remove mud flaps depending on tyre size (33" on GQ and 35" on GU are both pushing your luck). Zordo does say in his first post about the longer lowers causing super big tyres to hit the mud flap. I would be interested to know what tyre size, Zordo was talking about. For a 4" lift + I would class a 33" tyre as average for a GQ. Rim offset and the flex (angle the tyre goes into the guard) are also factors.

I also disagree about the point of fitting upper adjustable arms as well as +15mm lowers. Unless your bushes are worn on your old uppers, then I would be spending any more money on the uppers. (If you had a SWB then adjustable uppers are always recommended unless you need a bent upper arm to clear an after market fuel tank. In this case, lower adjustable arms are the best solution)

The tyre is going to sit 15mm further back when the tyre is compressed up into the guard. Everybody can take some measurements themselves to easily see what I am saying next time you go bush and flex it up.

A few years ago now, a customer of Superior Engineering couldn't wait for the standard length trailing arms so they fitted only what Superior had in stock, the +15mm arms. They went wheeling that weekend with the near new GU and the tyre smashed their guard doing a lot of panel damage as it crushed the guard up.

I am not trying to be smart here. This information could save someone a lot of money especially if they have a brand new Patrol.

Shane
 
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