making your own suspension components?

**c.h.i.e.f** · 7th April 2012, 09:56 PM

recently i have pulled my rear trailing arms out of my county as i have bent them due to lift and to much flex on the standard arms

so like everything else i have pulled apart at the moment i thought it would be usefull to look into options for trailing arms and a few other components.

well with the trailing arms i looked into QT rose jointed ones as i believe they will give the maximum articulation as possible but after looking at them i thought why cant i make them myself

so i started looking at chromoly tube (4130/4140) heim joints (rose joints) and making some myself for half the cost and probably stronger and also the same for the panhard rod so then everything is adjustable,capable and strong BUT when i started looking into it theres some problems

when i started investigating further as i wanted to be able to get it engineered for road use the big problems started

1. heim joints transmit vibration due to no rubber etc etc and hence do not progressivley wear like rubber does which is the first strike against them.

2. trying to find an engineer let alone one that wanted to talk about it was a mission as most of them are very arrogant and did not wish to help at all

3. once i found a few that would talk they said that the problem being is trying to prove if the homemade ones are as strong as standard which i then said "if you look at the standard ones and how easy they bend a piece of polly pipe would be stronger" so using thick walled 4130 tube with top quality heim joints or mar joints from marlin crawler offroad would would effinately be stronger did not have a valid point as the engineer then said he would need to sit there and do calculations on metals used and there qualitys and at $200 an hour he siad its a costly exercise

4. the engineer then said although if i can find a component that is designed for my vehicle such as a kit it would be easy to get engineered compared to making my own which brings me onto number 5.

5.i came across some joints called "jonny joints" made by some fella in america by his company called currie industries... as these joints have great flex and also incorporate urathane bush inside i believe they would be perfect but with further investigation i found that giglepin make a set of tailing arms that are 300mm longer and incorporate jonny joints either end but what i want to know has anyone used them? done the mod? has anyone made there own? anyone suggest good engineers around the nsw area?
or any ideas at all would be good to hear.

regards
mathew

**chazza** · 8th April 2012, 07:19 AM

I haven't done any suspension mods Mathew but like you I like to make things and I have recently been studying the licencing regulations both nationally and locally. Check out the DOTAR website, which mentions rose-joints.

Your engineers are quite correct that they must do the calculations for each part and this will cost big money, which is probably why suppliers charge a seemingly large price for their parts.

For myself, I stay clear of modifying suspension; steering and braking systems because they are safety sytems and the result of failure may lead to killing another motorist and being legally liable for any lesser damage

Maybe it is better to buy a part; provided the seller can guarantee its legality/fit-for-purpose status,

Cheers Charlie

addendum - here is the link which describes everything legal about modifying suspension http://www.infrastructure.gov.au/roa..._2011%20v3.pdf

**c.h.i.e.f** · 8th April 2012, 09:12 AM

thanks for that chazza you think i could find that info anywhere

its annoying that the strength of "stuff" that can be made by ourselves is way stronger than factory stuff but still cannot be allowed..

**CraigE** · 8th April 2012, 09:34 AM

I think there are still some posts on here from when I replaced mine. From memory the rose joints are an illegal mod. Hence whay I was directed away from them.

**chazza** · 8th April 2012, 10:42 AM

The pdf does mention that rose joints - having no give - can stress the suspension mountings, causing failure at the body; whereas rubber and plastic don't have that problem,

Cheers Charlie

**uninformed** · 8th April 2012, 10:42 AM

at what point do you need rose joints? thats one of the many questions you should ask yourself

**c.h.i.e.f** · 8th April 2012, 12:02 PM

Hahaha the point of bending standard arms and trying to keep everything together with the rediculous amount of torque of the Isuzu hence longer arms I was considering ... I am thinking of just buying the gigglepin ones getting them engineered and then be done with it...

**uninformed** · 8th April 2012, 12:45 PM

wy dont you email Gigglepin and ask if they can make them with the standard pin at the chassis end. BTW it is not the bush design that is the downfall of your links.

You may also want to check the relation between the length of the Gigglepin arms and the length of the A frame. Pinion angles are going to change over stock during bump and droop. Im not sure about your rig, but on mine, if I lengthen the TA by 300mm I would have to design a new body outrigger to allow for the TA to pass under it ...or make a new one with the TA mount incorperated in it. Then of coarse your engineer has to be happy with all this.

Your rear end is the least of your problems IMO. its trailing not leading......

**c.h.i.e.f** · 9th April 2012, 08:45 AM

Originally Posted by uninformed

wy dont you email Gigglepin and ask if they can make them with the standard pin at the chassis end. BTW it is not the bush design that is the downfall of your links.

You may also want to check the relation between the length of the Gigglepin arms and the length of the A frame. Pinion angles are going to change over stock during bump and droop. Im not sure about your rig, but on mine, if I lengthen the TA by 300mm I would have to design a new body outrigger to allow for the TA to pass under it ...or make a new one with the TA mount incorperated in it. Then of coarse your engineer has to be happy with all this.

Your rear end is the least of your problems IMO. its trailing not leading......

yeah in an instruction manual for the gigglepin trailing arms it demonstrates how to mount the new chassis mount 300mm further up the chassis...as we both know the limiting factors in the rear end is the trailing arms length/construction and the aframe ball joint bind.. unfortunately i dont know if there is enough room between the chassis rails to get the recommended 45deg angle to get rid of the aframe and replace with a triangulated setup

i could easily make some trailing arms the same as gigglepin ones but the problem then will be getting them engineered

as for the front i personally cannot see how it can be made any better and still be able to be legally driven on the road..if i didnt want to drive it on road i would make it a parallel 4 link front and triangulated 3 link rear with coilovers but i doubt that would be engineereable...

**uninformed** · 9th April 2012, 09:02 AM

the thing is most of the trucks that have had Giggle pin arms fitted to are 90's and some of these extended out to 100inch WB. So the outriggers are different to begin with, and secondly, the ones with 100in WB have a A frame extendtion. This means they are using the stock A frame arms and chassis mounts and moving the rear axle rearward. This makes the A Frame 7 inches longer (92.9 Vs 100) or 175mm, which means the new 300mm longer TA are not so much of a length difference to the A frame and have less pinion change.

The A frame ball joint while it does limit out at 21 degrees or so, its not the problem. Many have used it with ALOT of travel. Its all in the link design and geometry. If you are going custom you have to start thinking outside the box to make it fit in the box....for exampl if you want a longer A frame but are worried about keeping 45 degrees of angularity, mount the ends on the chassis rather than inbetween, you will have a bend in the arms to clear....that will require some good material and design. This is why anything and everything needs a mech engineerer.

The front can be made better by making longer RA. There are non rover guys making longer RA for rigs that are getting engineered in QLd. If it can be done here, it definietly can be done in NSW, that is for sure

Im very interested in suspension links etc and would have done all this by now, all legal and engineered designed, if it not for $$$. I have done some asking around, but you only get so much time for free....understandably.

Find non rover guys doing what you want, speak to them and find out their engineers plating their rigs. This may give you more options in your area

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