Link lengths,is this long enough?

[georgey]

Thinking about buying some 880mm long chromo trailing arms for a dual tri 4 link.
Will 880mm be long enough?
The arms in question are for sale in the classifieds section on here.
I've heard of people using 1100 uppers and 1300 lowers so I'm thinking 880 wouldn't be enough for a duel cab lux,wheelbase us around 125" atm

[91Mav]

880mm is longer than Patrol lowers and they flex good - just with a bit of rear steer and anti squat.

Figure out what sort of lift you plan on running, where the lower links will bolt to the diff housing and then on what angle the controls arms will be on. Up to 10 degrees and they should be fine.

[5inchgq]

Figure out what you want the truck to do then use the four link calculator to get the lengths that will work.

[AFeral]

Depends on how much suspension travel your going to have, the length of your upper arms and the other 1000 variables involved with suspension set up. So long and short of it, yes lower links of this length can be made to work well. If links of this length will work for you, depends on your driving stile and the rest of your setup.
Also worth noting the long the the links the easyer they are to bend.

[georgey]

I looked at the link calculator once....and I don't understand how to use it nor am I going to try,so no calculator for me.

Good point about long links bending easier Aferal.
I think 880 should be long enough for the lowers.
Patrols don't flex too bad and their links are fairly short.

Setup will be 40" tyres,16" coilovers in rear 18" airs in front until I buy 16" coilovers.
Hoping dual tri front and rear,if the sump is in the road I may do a 5link,
What other options for front link setups would you recommend?

Thanks

[5inchgq]

I looked at the link calculator once....and I don't understand how to use it nor am I going to try,so no calculator for me.

Why not try and understand it ??

Just trying to understand why you don't want more knowledge of mods if thats what you are trying to do for a living Justin ??

[NICK]

mine are 1480, hope this helps


NICK

[80's_delirious]

80 series lower links are approx 880mm long, and are not triangulated at all. if you are going to triangulate links, I think they will need to be longer, having them on an angle effectively reduces the length.

I have bent laminated 80series lower links

[georgey]

I looked at the link calculator once....and I don't understand how to use it nor am I going to try,so no calculator for me.

Why not try and understand it ??

Just trying to understand why you don't want more knowledge of mods if thats what you are trying to do for a living Justin ??

Ive sat there for around an hour and couldnt understand where to find all the measurements and figures the calculator requires,and noone that i know knows how to use it properly either.
Everyone ive spoken to including a few TT competitors and builders have told me not to worry about the calculator and just to keep everything symetrical and and parralell.
Tack the mounts in,cycle suspension and change as required.

Not really looking to do mods for a living either im quite happy with what im doing at the moment,im rather doing mods and stuff for a bit of extra coin and the experience.


i might give the 880mm arms a pass then as i think they may be too short for my liking.
They are for sale for $400,but for the price i think i can buy some heavy walled seamless and make all my links and have money left over.

cheers for all the responses and if anyone wants to show me a guide to the 4 link calc it would be much appreciated.

cheers

[Jcas24]

look in the co-ordinate tab on the link calculator and it gives you the X Y Z measuring points.

X- is the distance forward from axle centreline
Y- is the distance out from vehicle centreline (horizontal seperation)
Z- is the distance from the ground to the mounting point.

I've being doing one for my rear 3-link and it does my head in, but I got something to work off for building it. I want to know the anti squat, but seen as I have no triangulation I know my roll axis is up to s#!t. It will most likely handle like a dog but I can't do alot about it with the setup I want. Im just trying to keep things as flat and low as possible. Its not a DD

[MogLux]

My lowers are about 1100 long uppers about 900 from memory... link separation with the mogs will be about 12inches at the diff and about 2-4 inches at the chassis...
Iv got a calcualtor i downloaded but never really sat there to work it out... as previously stated most will have info tabs if you wave the icon over them..

[91Mav]

Hi mate,

Have a read of this tech article on Petersen's site: http://www.4wheeloffroad.com/techarticl ... index.html" onclick="window.open(this.href);return false;.

[georgey]

cheers matty,those lengths sound a bit better.I want to go good on the ramp but also want it to be stable and perform well.

Im going to try and make the links as flat as possible and maybe try and run the top arms flat with the chassis and raise the mounts on the diff if thats possible.

Ill have another crack at the calculator this afternoon.
Which calc are you using jase? theres a few different ones.


Cheers for that 91mav,i read it while i was trying to work it out last time,will have another read soon.

thanks guys

[georgey]

In regards to the link calculator-

If your tire size and track width changes will the links need to be changed?
i have 36'' swampers for now but will be buying 39.5 iroks or 40'' treps.

Also if the the wheelbase changes will the links need to be redone again?
ill be doing the front first and then doing the rear after.so the wheelbase may change slightly.Or should i do it all at the same time?

[91Mav]

The separation of the uppers and lowers at the diff will need to increase with larger tyres. The separation should be at least 1/4 of the tyre diameter. Eg. 36" tyres = 9" separation, 40" tyres = 10" separation. I would go 10" and you can run up to 40". This can get a little tight if you try and keep the car real low.

[AFeral]

Understanding what is involved with suspension is not easy have a read of this for a good starting point

http://hstrial-4wheelundergr.intuitwebs ... n-411.html" onclick="window.open(this.href);return false;

[georgey]

Cheers for that link Aferal,was a very good read!!

[DUDELUX]

Send Dex(V840) a PM about using the link calculators, Ive seen the info he had written down after using one of them, quite alot of pages with tech looking drawings and info.

He might be able to shed some light for you Justin.

[georgey]

thanks tony,pm replied to also

[v840]

I think the link calculator is an invaluable tool, however I reckon it should be more seen as a guide rather than an exact measurement. The fact that most of the results (squat, RA etc.) are based on the vehicle's centre of gravity and most people will just estimate where this point is renders a lot of the supposed readings a bit null and void.

I still think it's great for getting a baseline idea of where everything's going to be sitting but it's by no means exact without knowing your specific CoG.

Justin, sit down with a book of graph paper, a compass, a pencil, a tape and print out the Petersens article. Go through it. You'll end up taking around three hours most of which will be spent on your back under your truck working out where everything will go but it'll be worth it. You'll also end up with about thirty pages of notes. Trust me, you'll learn heaps and if you're interested at all by suspension will find the whole process rewarding.

http://www.orcfab.com/tech/4link1.html" onclick="window.open(this.href);return false; Just in case you missed 91Mav's post Combined with AFeral's link you should be able to work out exactly what you want. Doing it next to your truck makes it a whole lot easier to understand IME.

Mind you, many people have had great success with their links by simply keeping them flat as possible, as long as will fit, as vertically seperated as practical, and as angled as they can make them. Given that you're not going to be road driving your bus I almost wouldn't worry about the specifics.

Good luck with it dude.

[georgey]

thanks heaps for the advice dex.

i will be ordering link material this friday,my transfer adaptor also comes this friday,ill do the adaptor this weekend and the link material should be here through next week

Is it worth going solid bar or just some heavy wall seamless tube.

Also thinking 5 link or A frame front to clear the sump,AFAIK the calculator only works for 4links?correct?

are there other calculators?

Thanks alot for the answers guys,been a great help

[v840]

Have you thought about a 3-link + panhard for the front? There is a calculator for this as a front setup by the same guy off Pirate, Triaged.

It's essentially the same thing with a few minor diffrences (anti-dive as opposed to anti-squat etc.) and again, is a great way to work out roughly where everything should be.

I'd be a bit wary of a 5-link. They often bind up under flex if not designed properly. A dude I know had one on the front of his 80 and he went through bushes pretty much every wheeling trip...
3-link +phard takes up less room, requires fewer bushes/joints, is cheaper to buy parts for and works just as well if not better.

[TWISTY]

Also thinking 5 link or A frame front to clear the sump,AFAIK the calculator only works for 4links?correct?

For the front and sump clearance, triangulate the lowers and run parellel uppers. Will help with sump clearance. Seen a few setup on Pirate this way.

[joshy]

ive sort of done what twisty said, i the front my lowers have most of the triangulation and the uppers while still angled are less. Seems to work for me. Pete A runs his the same.

[brooksy]

Exactly what I am doing with current build & my own 40 ........when I get around to it ... lol

I have the front set-up with uppers parallel'ish & lowers triangulated merging closer at chassis. Having links wide at the housing gives better support & control. Rear will be reversed with triangulated uppers (merging at housing) & parallel'ish lowers.
This set-up is widely used in Ultra4's & other KOH rigs.
As far as squat goes have your uppers adjustable at the chassis mounts with at least 3 holes (front) & 4 holes (rear) set at 25-30mm apart. Roll axis can be a little more difficult but comes down to how high you can set-up the links to eleviate excessive upper roll response to suspension geometry.




brooksy

[Micka]

Exactly what I am doing with current build & my own 40 ........when I get around to it ... lol

I have the front set-up with uppers parallel'ish & lowers triangulated merging closer at chassis. Having links wide at the housing gives better support & control. Rear will be reversed with triangulated uppers (merging at housing) & parallel'ish lowers.
This set-up is widely used in Ultra4's & other KOH rigs.
As far as squat goes have your uppers adjustable at the chassis mounts with at least 3 holes (front) & 4 holes (rear) set at 25-30mm apart. Roll axis can be a little more difficult but comes down to how high you can set-up the links to eleviate excessive upper roll response to suspension geometry.




brooksy

Same same on my Rangie/Series Truggy. Except I'm going for a double tri rear. The front with the parallelish uppers and tri lowers merging at the chassis is the only way I could keep it as low as possible...well as low as portals and 40s allow anyway.

Micka

[georgey]

Thanks heaps guys.
Think i will do what brooksey said and tri the lowers and slightly angle the uppers around the sump.


Would solid bar or thick wall seamless be better?
Im thinking solid but it is alot more weight over tube,Also what is a good size.
i will be running heim joints all round.

thanks again

[lukethedork]

I think the link calculator is an invaluable tool, however I reckon it should be more seen as a guide rather than an exact measurement. The fact that most of the results (squat, RA etc.) are based on the vehicle's centre of gravity and most people will just estimate where this point is renders a lot of the supposed readings a bit null and void.

My understanding is that the calculator also assumes 100% weight transfer. Maybe correct on steep climbs, but then your COG has effectively changed anyway....

Also thinking 5 link or A frame front to clear the sump,AFAIK the calculator only works for 4links?correct?

are there other calculators?

The 4link calculator will work on A frame suspensions. To create an A-arm, just place the two control arms at the same 'XYZ' where they converge.

My lowers and uppers are both triangulated. Lowers about 10* and uppers approx 16* if I recall correctly...

Luke.

[ISUZUROVER]

Would solid bar or thick wall seamless be better?
Im thinking solid but it is alot more weight over tube,Also what is a good size.

Weight for weight, round bar will be stronger than solid, because it will have a larger diameter - which is the important issue.

So basically, to get the strongest link, you want to use the largest diameter you can, with sufficient wall thickness so it doesn't dint/bend when impacted from the side offroad.

Solid bar just adds weight without any extra strength.

Personally I would use at least 32NB.

[georgey]

sweet ive already got some 32nb here so i can start making them