Wanted: step by step radius rod modification information

YouTube · Post by **El_Freddo** » Thu Mar 03, 2011 12:26 pm

Ok - after searching the forum for the answer to longer/adjustable radius rods all I've come up with is that the falcon X something rods can be modified to do the job. Disco says they're crap not worth looking at - and I'm not keen to have anything ford on my subaru

Has anyone out there got pics and details of their setup? I'm after a step by step guide as to what exactly I need and how to do it.

Aim is to push my front wheels forward back to the factory position or a little further forward. I think the lift kit has pulled the wheels towards the rear as it is a 3 inch lift with 2 inch blocks on the radius rod plate - to keep the wheel in the same position with this setup the radius rod needs to be longer...

If anyone can help with this it would be greatly appreciated.

Cheers

Bennie

Post by **Alex** » Thu Mar 03, 2011 12:44 pm

although i dont have a guide for you i looked into this years ago, a custom set would be easy enough to make and a very viable option.

heard about the falcons as well i think it was a XC will fit. Also something rings a bell about a silvia or something will fit.

while youre at it, go for an upgrade, the day will come when you bend a radius rod. (RX turbo run a thicker radius rod)

this is what happened when i bent mine...i just replaced it with the standard jobby, but i do remember discussing making a custom set up. Not sure if its documented on here though.

spike · Post by **spike** » Thu Mar 03, 2011 3:07 pm

i only just saw the other thread
and well as a bit of a revival would anyone be interested in designing some chromolly ones??

im happy to give it a shot making them

YouTube · Post by **El_Freddo** » Thu Mar 03, 2011 4:09 pm

Yeah Alex I've seen the result of hitting stuff hard - just not on my L

Hopefully I won't be in that situation.

That is one seriously bent radius rod and control arm! I realise you went hard but that's a real bad hit to the wheel!

Cheers

Bennie

isnowi · Post by **isnowi** » Thu Mar 03, 2011 5:33 pm

Silvia/200sx use a tension rod setup, they're not designed to work in compression as the subaru ones are. One setup that i was looking at relplicating was the mk1 escort compression strut kits. The use a universal type joint at the bottom arm, and a rose joint onto the chassis rail.

The universal goes through the bottom arm on an escort.
A setup like this would allow for a lot more articulation as the compression rod can change it's angle to bot the chassis and the bottom arm more easily.

I was looking at making a rod with rose joints both ends, a new bracket for the chassis end, and another bracket for the bottom arm using the existing holes in the arm to mount to.

steptoe · Post by **steptoe** » Thu Mar 03, 2011 11:01 pm

I think Bluesteel in tassie was making them up for $100 a pair some long time ago. XR 1967 uo late 1987 XF used much the same if not same castor bar

Matt · Post by **Matt** » Thu Mar 03, 2011 11:19 pm

Brumby Boy and i designed up and made some not that long ago for me and him... Wait for his reply here....

But they would not be ADR approved, strictly for offroad use. Disclaimer complete!

But are fantastic rods and have no chance of bending... lol! Trust me i have tried a few times, lol! However it may break the mount instead eventually

discopotato03 · Post by **discopotato03** » Fri Mar 04, 2011 11:17 am

I can tell you exactly who can get them made up in NSW . I'd ring Stewart Wilkins Motorsport or or is it Rallying .

They get things fabricated for Rally car suspension all the time and they get radius rods made up often enough . I can't quote the grade of steel they use but they call it "60 tonne steel" from memory .

Really in an L Series you need to make changes both the radius rods and the control arms . The control arms particularly have quite small diameter inner end bushes and they don't take kindly to being moved too far backwards or forewards .

We cheated with my radius rods by packing up the steel washer behind the foreward or body mount ends and making up a bush to go over the rear of the threaded section for the outer washer to crush up against . I have modified Nissan Bluebird urethane bushes (modified by having heated cherry red bar put through them to get the bore size up to Subaru spec) hey 5 min job and cheaper than buying new since I owned the Nissan ones !
Anyway the idea was to use the full length of the OE rods because normally they have something like 15-18mm of thread in front of the jamb nut .

The control arms sit 15mm further forward (where they bolt the radius rod on) and change the caster from negative towards positive - positive direction literally . I had my control arms remanufactured (one set made of two) to make them longer and angle more forward at the bush junction to take the radial load off these bushes .
DON'T get too greedy with length because there is a limited amount of plunge depth in the DOJs and if you go too far they can pull out and smash around underneath . XT6 shafts are the next increment longer in the L platform family and 1st gen Lib after that . Always wanted XT6 front shafts ...
The result is the first L Series I've EVER seen with static negative camber though the caster change is the greatest improvement .
I'm really sorry now I didn't find ways to get more positive caster and rather than custom rods I'd have first looked at mods to the body mount brackets to see if they could be altered to sit forward a little positioning the rods and arms further forward .

Whatever you do be VERY sure of the people doing ANY alterations and fabrication because failures here can kill you and others very easily .
I trust AJ unconditionally because he's Rally'd was he's made over a lifetime and likes living too .

A .

stenno · Post by **stenno** » Fri Mar 04, 2011 3:16 pm

Anyone know if Toyota AE86 tension rods are suitable? they look like the "right" shaped ends.

picture and for sale here :
justjap.com

very vague dimensions here:
megan racing

I might suck it up and find out in the next few months

isnowi · Post by **isnowi** » Fri Mar 04, 2011 7:01 pm

stenno wrote:Anyone know if Toyota AE86 tension rods are suitable? they look like the "right" shaped ends.

picture and for sale here :
justjap.com

very vague dimensions here:
megan racing

I might suck it up and find out in the next few months

Remember they are designed to work in tension, may not stand up to the compression loads that subaru suspension generates.

Post by **yarney** » Fri Mar 04, 2011 7:49 pm

The only thing about having heaver radius rods is if you hit something hard they wont bend but something else major under the car will

Jan

RSR 555 · Post by **RSR 555** » Sat Mar 05, 2011 10:54 am

stenno wrote:Anyone know if Toyota AE86 tension rods are suitable? they look like the "right" shaped ends.

picture and for sale here :
justjap.com

very vague dimensions here:
megan racing

I might suck it up and find out in the next few months

I'd take the Subaru one down to your local Toyota wrecker and put the side-by-side and see what it looks like.

yarney wrote:The only thing about having heaver radius rods is if you hit something hard they wont bend but something else major under the car will

Jan

Yeah true.. I would be interested in it for the alignment properties

Post by **TOONGA** » Sat Mar 05, 2011 11:21 am

You may even look at the radius rods from a Honda oddesy

having pulled one to bits on thursday I did notice the radius rods are longer than the L series or brumby ones

I was going to get photos but the left overs were wisked off to the scrap bin before I had a chance too

one side would be good to use the other side looked very strange but Im sure you could get two of one side to make a matched pair

TOONGA

2coupedup · Post by **2coupedup** » Sat Mar 05, 2011 12:19 pm

hey, Done a radius rod and control arm mod on an MY series, made my own radius rod to get pos. castor, everybody says they are sure to bend because they are longer and therefor weaker but 2 years of quite abusive driving and the only thing to go so far is the crappy stock rubber bushes...

check it out here 4x4 conversion coupe plus

maybe some ideas can be taken for L-series...

YouTube · Post by **El_Freddo** » Sat Mar 05, 2011 5:11 pm

Thanks guys for all of your input. Jeff is going to email me a some pics of how to sort one out...

Thanks 2couped, I've read your thread quite a number of times, I'm just not keen on the "joiner" near the end, I'm sure its all good but I want something that works and looks factory enough for a cop not to take a second look at it.

Jules, what year odyssey were you looking at? I've not seen any in the parts yards that I "frequent" yet... Might be something to look into though.

I'd rather be using a compression radius rod than a tension one only to be on the safe side...

Cheers

Bennie

2coupedup · Post by **2coupedup** » Sun Mar 06, 2011 6:25 am

maybe some 20mm round bar with the end flattened out and the other machined down and an 18mm or so thread turned onto it??? thats my next adventure (along with more adjustability and travel, also expanding and lengthening the rear lol) should be fun...

but it realy would be nice to get ball or eye joints either end to allow for a "free er" easier articulation of the arm without flexing the bushes at the same time... hmmm if only i had some $$$

discopotato03 · Post by **discopotato03** » Sun Mar 06, 2011 1:26 pm

What you have to remember is that these compression struts don't rise and fall as far as the outer ends of the control arms do .

Again your calls but I would not use spherical joints on them because they have NO compliance whatsoever and as always they transmit a lot of noise and vibration into the body shell/cabin area .
They also get crud in them and wear/rattle frustratingly .

There is only one safe effective way to have them made and thats in the right dimensions and grade of steel .

The way we did it maximised the use of factory parts so it looks virtually std and works better than std . It could have been better and cost more but you have to stop somewhere .

A .

Post by **TOONGA** » Sun Mar 06, 2011 1:41 pm

here's how Phizinza made his modified radius rods

http://offroadingsubarus.com/83sedan_radiusrods.html

TOONGA

discopotato03 · Post by **discopotato03** » Sun Mar 06, 2011 6:21 pm

As people who know early Subaru front geometry will tell you from the factory they have significant negative caster and positive camber , both are really the wrong way around .
What moving the lower or foot end of the strut forward does is give dynamic camber change meaning both steering wheels will lean their tops towards the corners apex and keeping more of the total width of BOTH tyres on the road .
What moving the caster settings in the positive direction also does is increase the steering effort even on cars with power steering . Really power steer becomes essential with this and many early Soobs don't have it .

Best case scenerio , in my book anyway , is moving caster in the positive direction , avoid static negative camber , keep wheel offsets as CLOSE to standard as possible .

You have to take into account things like squat under heavy braking because when the nose dives the geometry changes and not always for the better . Subarus also want to stand the front end up in the air like a bloody preying mantis if they have reasonable or added grunt . This also changes the front end geometry and often causes all sorts of front traction issues .
With a std height MY/L the front control arms angle downwards laterally , so , if the nose dives they level out pushing the strut feet and wheels outwards as well . They do the reverse when the front reaches for the sky . The result is negatively biased camber change going down and positive going up .
With body roll they go in opposite directions .

Now some disagree but part of the sollution with my 86 RX Sedan was to fit one off made larger diameter anti roll bars back and front . Big difference because less body roll means less diabolical geometry but it doesn't stop understeer if the camber is positive and caster negative . It just understeers less because of the greatly reduced roll camber change in the wrong direction .
Step 2 was to pack the compression struts as far as possible which gives about 13-15mm difference in comp' strut length .
Step 3 was modified front control arms to get the static camber from grosley positive to neutral or a hair negative .
Optional step 4 was to fit Noltek urethane suspended adjustable strut tops to push the positive caster situation as far as possible from the TOP of the strut .
I don't know about MY's but L's are a bastard because the front strut towers place the strut tops too far forward and it would require metal fabrication along with small diameter springs and hats to get the struts ideally where you want them . Tis ALWAYS better to change strut angles from the top because the control arm and the struts pivot axis through the ball joint remain almost std , so do the wheels positions in their wells .

It is far from impossible to make an L or MY front end work properly but you have to look at all aspects of the system and change all of them to suit . You can't really overlook things like lack of power steer/non standard wheel offsets/heavier wheels/tyres/drive shaft angles/lengths because they all play their part in the overall system . Its rare to be able to change one thing and get an advantage without have to change other things around it .

Also be VERY carefull using tension rods in the place of compression rods because most steels are much stronger in tension than compression so if you reverse the stresses theres no guarantee they'll survive compressive loads reliably .
You life may well hinge on these rods NOT failing so its one area you do NOT want to underengineer . If properly made compression struts owe you $250-$300 its a small price to pay for piece of mind . What price do you place on your life ?

A .

stenno · Post by **stenno** » Sun Aug 21, 2011 2:30 pm

bumping this up again

Disco, what are your thoughts on using these compression rods for a L series armed brumby. already used in compression from the factory but the radius rod mounting hole may have to be clearanced a little to get them to fit.

from this model van