Flipped Radius arms

[Graham Stirling]

Can someone please point me to some info and pics showing flipped radius arms. I've been searching for a couple of days but can't find what i'm after.

I'm about to fit 5 inch coils to my 80 and want to know how hard it is to flip the arms and is it worth it.

Cheers, G

[Struth]

Researching this myself ATM with 80s arms on 60s diffs.

It wouldn't be real hard if you can fabricate, providing it doesn't interfere with stearing parts.

Apparently (read according to this months 4WDnoaction) it places the radius arm and bushes in a more neutral position when sitting level (pre travel up or down) which makes sense to me for the chassis end bush but not really for the diff end bushes which I think would remain the same re neutrality.

Cheers

[Graham Stirling]

Cheers, fabricating isn't a problem. I'm looking to gain some clearance under the axle and i want to save the cost of castor plates.

I assume that it's just a matter of cutting off the mounts and fabricating new mounts on top of the axle. But, what i'm wondering is how to measure the castor to make sure that the axle sits at the right angle.

[Weiner]

Cheers, fabricating isn't a problem. I'm looking to gain some clearance under the axle and i want to save the cost of castor plates.

I assume that it's just a matter of cutting off the mounts and fabricating new mounts on top of the axle. But, what i'm wondering is how to measure the castor to make sure that the axle sits at the right angle.

Can't you use an angle finder on the top of the swivel hub and get it at the same angle when you put the new mounts on?

[lokka]

Cheers, fabricating isn't a problem. I'm looking to gain some clearance under the axle and i want to save the cost of castor plates.

I assume that it's just a matter of cutting off the mounts and fabricating new mounts on top of the axle. But, what i'm wondering is how to measure the castor to make sure that the axle sits at the right angle.

Can't you use an angle finder on the top of the swivel hub and get it at the same angle when you put the new mounts on?

Thats the best way to do it with the angle finder tho id like to see pics of how this mod is done as on the short side there wouldent be much room for both the arm and the coil to mount up neatly

[Graham Stirling]

Cheers lads.

Once i get the axle off and cleaned up i'll look at how it will all fit together. I'll post some pics when it's done. G

[MUD80D]

like this one








and flex like this

[lokka]

great pics man looks like a good mod to get them low slung arms up out of the way
Its a tight fit in there tho looks like a fairly simple mod did you do a cut and rotate of the swivels at the same time

[MUD80D]

swivels are not cut and caster is +3

[pinkfloyddsotm]

[Struth]

I like the idea of that transmission/radius arm mount in one, will investigate that further.

Good photos thanks.

[pinkfloyddsotm]

I like the idea of that transmission/radius arm mount in one, will investigate that further.

Good photos thanks.

yer the radius arms dont line up within the 75 chassis so i made them to suit under a new crossmember, and to "graham stirling" yea its a PITA to flip the arms and get the castor right and cut the bracket to suit, i had one person eitherside of the diff hold the castor in place while i welded the brackets in good,like no spot tacks otherwise soon as you let go it just rolls back so yer..and also you might have to make new brackets if its easier,just use 5mm plate.you will also have to raise the diff end panhard rod mount up 70mm or so to clear the front part of the radius arm, if you need pics just ask. good luck.

[Evil 73]

I did a radius arm flip on my 75 series with 80 diffs, i just bought a set of castor correction plates bolted them to the arms set the castor and pinion angle and welded them to the diff, i was able to use the old leaf spring hangers on the chassi end and bolt the arms straight in with a small spacer.

I also incorporated the coilover mounts into the castor correction plates for more torsional/sideways rigidity, and then the diff gussetting on the other side, so i short plenty of meat to weld to.

Ben

[pinkfloyddsotm]

I did a radius arm flip on my 75 series with 80 diffs, i just bought a set of castor correction plates bolted them to the arms set the castor and pinion angle and welded them to the diff, i was able to use the old leaf spring hangers on the chassi end and bolt the arms straight in with a small spacer.

I also incorporated the coilover mounts into the castor correction plates for more torsional/sideways rigidity, and then the diff gussetting on the other side, so i short plenty of meat to weld to.

Ben

yer thats another good idea, but its hard when you live in perth and everything comes from over east which is a two week wait..
got any pics of your 75 man ?

[Graham Stirling]

yea its a PITA to flip the arms and get the castor right and cut the bracket to suit, i had one person eitherside of the diff hold the castor in place while i welded the brackets in good,like no spot tacks otherwise soon as you let go it just rolls back so yer..and also you might have to make new brackets if its easier,just use 5mm plate.you will also have to raise the diff end panhard rod mount up 70mm or so to clear the front part of the radius arm, if you need pics just ask. good luck.

Thanks for that lot, pics would be great cheers. If there's room i might try drilling the plates after they are welded in rather than trying to trim drilled plates to suite the axle.

[RV80]

yea its a PITA to flip the arms and get the castor right and cut the bracket to suit, i had one person eitherside of the diff hold the castor in place while i welded the brackets in good,like no spot tacks otherwise soon as you let go it just rolls back so yer..and also you might have to make new brackets if its easier,just use 5mm plate.you will also have to raise the diff end panhard rod mount up 70mm or so to clear the front part of the radius arm, if you need pics just ask. good luck.

Thanks for that lot, pics would be great cheers. If there's room i might try drilling the plates after they are welded in rather than trying to trim drilled plates to suite the axle.

Overkill Engineering makes the plates to do the arm flip. Give Sam a call to see if they still do them.

[Graham Stirling]

Cheers bud but i'm in Scotland so not so much available off the shelf unless it's Landrover. If i struggle to fabricate something i'll see if i can import a kit.

[1MadEngineer]

so what is the advantage of flipped arms? apart from a little bit of clearance? surely you would be far better off shaving the bottom off the diff..... (also quicker and easier). I just find it weird that you go to all that effort for no extra flex, but a slight gain in clearance waaaay out near the tire which has good clearance when driving obstacles. Yet not 1 in those pics has shaved or plated the bottom of the diff!! for clearance where you need it most...... sorry i must be missing something, but i just don't get it.

[bj on roids]

so what is the advantage of flipped arms? apart from a little bit of clearance? surely you would be far better off shaving the bottom off the diff..... (also quicker and easier). I just find it weird that you go to all that effort for no extra flex, but a slight gain in clearance waaaay out near the tire which has good clearance when driving obstacles. Yet not 1 in those pics has shaved or plated the bottom of the diff!! for clearance where you need it most...... sorry i must be missing something, but i just don't get it.

When you have big lift, it allows you to run stock arms and bushes and have stock caster (Biggest advantage I can see)

Additional leverage on the arms would probably increase the flex a small amount too...

[RV80]

One advantage of the flipped arm is the added clearance of the tie rod, standard arms hit when underneath with a big lift.

Grant

[MUD80D]

before i done the arm flip i was bending the arm with an 7.5"lift the arm sat at about the 45 deg angle so when you hit a log or rock in comp or winching instead of the diff moving up it wanted to go back because of the angle of the arms using my cruiser in comps i was bending the arms each event and was a pain in the ass so now putting the arms on top of the diff they become level as if they were back to standard and since the arms have been on top NO arms have been bent last year i competed in the toperi challenge and powering up a hill and hit a large rock if the arms were on the bottom i would have bent them good but now there on the top no problems even thow i hit this rock thet hard running 38.5"tires and broke my Longfield axel (not the CV) from the tire hitting a 3 foot step but with my arms on top i had to raise the panhard rod any way to suit my high steer.

[Graham Stirling]

It'll save me roughly £250 (Aus $550) on the cost of castor plates and should push the axle forward back to where is should be.

[Struth]

That sounds like two pretty good reasons to fip the arms to me, coupled with the relatively small gains a diff shave offers, then flipped arms should work well as far as getting as much as possible out of harms way goes.

Cheers

[1MadEngineer]

before i done the arm flip i was bending the arm with an 7.5"lift the arm sat at about the 45 deg angle so when you hit a log or rock in comp or winching instead of the diff moving up it wanted to go back because of the angle of the arms using my cruiser in comps i was bending the arms each event and was a pain in the ass so now putting the arms on top of the diff they become level as if they were back to standard and since the arms have been on top NO arms have been bent last year i competed in the toperi challenge and powering up a hill and hit a large rock if the arms were on the bottom i would have bent them good but now there on the top no problems even thow i hit this rock thet hard running 38.5"tires and broke my Longfield axel (not the CV) from the tire hitting a 3 foot step but with my arms on top i had to raise the panhard rod any way to suit my high steer.

sorry, but i don't get this? I do understand the bending bit, big lifts induce more of a bending force into the resultant which causes the arm to bend/twist in the wristed area (common problem in any radius arm coupled with a big lift). the bit i don't get is the anti-squat change???? it can't change, if all the mounting/pivot points are still in the same spot! In a RadArm setup AS is a function of contact patch - diff axle CL - mounting point on chassis. The only way to change AS on a radius arm (same tire dia) is to change the pivot point position on the chassis!!! changing the mounting on the diff will make no difference at all. EG: use the 3-link calculator on pirate and have a play. The only thing you will find is that it adjusts the RollAxis somewhat but that is more to do with articulation and handling.
as for the arms bending, once you go for a GOOD after market radius arm then thst should fix the problem.

Sorry for all the Q's but i am trying to learn more about cruisers and what is needed to make them better, and also peoples perceptions of what is the best way to go....

[lukethedork]

the bit i don't get is the anti-squat change???? it can't change.

I don't think this is correct.
I believe on a radius arm setup such as these, the AS % will increase dramatically as the angle of the links increases in steepness.

if all the mounting/pivot points are still in the same spot! In a RadArm setup AS is a function of contact patch - diff axle CL - mounting point on chassis. The only way to change AS on a radius arm (same tire dia) is to change the pivot point position on the chassis!!! changing the mounting on the diff will make no difference at all.

Again I believe this to be wrong.
I believe a change in the angle of the suspension links will change AS %.

Luke.

[1MadEngineer]

the bit i don't get is the anti-squat change???? it can't change.

I don't think this is correct.
I believe on a radius arm setup such as these, the AS % will increase dramatically as the angle of the links increases in steepness.

if all the mounting/pivot points are still in the same spot! In a RadArm setup AS is a function of contact patch - diff axle CL - mounting point on chassis. The only way to change AS on a radius arm (same tire dia) is to change the pivot point position on the chassis!!! changing the mounting on the diff will make no difference at all.

Again I believe this to be wrong.
I believe a change in the angle of the suspension links will change AS %.

Luke.

i don't wont to sound rude but please look at the link or the calculator.
You will quickly see the 'line of AS' runs from the contact patch through the pivot point/mount on the chassis. the angle of the arm has no influence on AS in a RA setup as they are almost deemed a solid fixture, more akin to a torque arm.

please read
http://www.pirate4x4.com/forum/showthread.php?t=204893
and enjoy

[lukethedork]

i don't wont to sound rude but please look at the link or the calculator.
You will quickly see the 'line of AS' runs from the contact patch through the pivot point/mount on the chassis. the angle of the arm has no influence on AS in a RA setup as they are almost deemed a solid fixture, more akin to a torque arm.

please read
http://www.pirate4x4.com/forum/showthread.php?t=204893
and enjoy

Took a proper look and I see that I am wrong.
You don't sound at all rude and I'm always happy to be corrected.

Thanks,
Luke.

[v840]

before i done the arm flip i was bending the arm with an 7.5"lift the arm sat at about the 45 deg angle so when you hit a log or rock in comp or winching instead of the diff moving up it wanted to go back because of the angle of the arms using my cruiser in comps i was bending the arms each event and was a pain in the ass so now putting the arms on top of the diff they become level as if they were back to standard and since the arms have been on top NO arms have been bent last year i competed in the toperi challenge and powering up a hill and hit a large rock if the arms were on the bottom i would have bent them good but now there on the top no problems even thow i hit this rock thet hard running 38.5"tires and broke my Longfield axel (not the CV) from the tire hitting a 3 foot step but with my arms on top i had to raise the panhard rod any way to suit my high steer.

sorry, but i don't get this? I do understand the bending bit, big lifts induce more of a bending force into the resultant which causes the arm to bend/twist in the wristed area (common problem in any radius arm coupled with a big lift). the bit i don't get is the anti-squat change???? it can't change, if all the mounting/pivot points are still in the same spot! In a RadArm setup AS is a function of contact patch - diff axle CL - mounting point on chassis. The only way to change AS on a radius arm (same tire dia) is to change the pivot point position on the chassis!!! changing the mounting on the diff will make no difference at all. EG: use the 3-link calculator on pirate and have a play. The only thing you will find is that it adjusts the RollAxis somewhat but that is more to do with articulation and handling.
as for the arms bending, once you go for a GOOD after market radius arm then thst should fix the problem.

Sorry for all the Q's but i am trying to learn more about cruisers and what is needed to make them better, and also peoples perceptions of what is the best way to go....

I'm not sure if he's saying he got any change in his AS%, I think he's just saying that having his arms on an increased angle, they hit more stuff and instead of wanting to slide over, because of the harsh angle, they would just get caught and try to push the diff back.

Leveling the arms out by flipping them put them back to a more acute angle and helped them slide over obstacles rather than hook up.

At least, that's how I read it?





P.s Lukethedork, good on you for having a great attitude mate! I wish more people were like you on this board!

[80's_delirious]

advantages I see of the flipped arms is:
- it returns the arm to a more horizontal position,
- moves the diff housing forward (spring lift will make the housing move rearward slightly as the downward angle on the radius arm increases with lift),
- allows caster correction to be done at the same time (or rotate knuckles as well to correct caster and pinion angles)
- gives a little improvement in ground clearance
- eliminates issues with tie rod hitting radius arms (as when caster plates are fitted)
- can be done for far less $$$ compared to buying dropped arms ( a few bucks in steel and some fab vs $12-1300 for drop arms)

disadvantages?

I would love to know what they are coz I have thought about doing arm flip on mine.

[80's_delirious]

before i done the arm flip i was bending the arm with an 7.5"lift the arm sat at about the 45 deg angle so when you hit a log or rock in comp or winching instead of the diff moving up it wanted to go back because of the angle of the arms using my cruiser in comps i was bending the arms each event and was a pain in the ass so now putting the arms on top of the diff they become level as if they were back to standard and since the arms have been on top NO arms have been bent last year i competed in the toperi challenge and powering up a hill and hit a large rock if the arms were on the bottom i would have bent them good but now there on the top no problems even thow i hit this rock thet hard running 38.5"tires and broke my Longfield axel (not the CV) from the tire hitting a 3 foot step but with my arms on top i had to raise the panhard rod any way to suit my high steer.

sorry, but i don't get this? I do understand the bending bit, big lifts induce more of a bending force into the resultant which causes the arm to bend/twist in the wristed area (common problem in any radius arm coupled with a big lift). the bit i don't get is the anti-squat change???? it can't change, if all the mounting/pivot points are still in the same spot! In a RadArm setup AS is a function of contact patch - diff axle CL - mounting point on chassis. The only way to change AS on a radius arm (same tire dia) is to change the pivot point position on the chassis!!! changing the mounting on the diff will make no difference at all. EG: use the 3-link calculator on pirate and have a play. The only thing you will find is that it adjusts the RollAxis somewhat but that is more to do with articulation and handling.
as for the arms bending, once you go for a GOOD after market radius arm then thst should fix the problem.

Sorry for all the Q's but i am trying to learn more about cruisers and what is needed to make them better, and also peoples perceptions of what is the best way to go....

I'm not sure if he's saying he got any change in his AS%, I think he's just saying that having his arms on an increased angle, they hit more stuff and instead of wanting to slide over, because of the harsh angle, they would just get caught and try to push the diff back.

Leveling the arms out by flipping them put them back to a more acute angle and helped them slide over obstacles rather than hook up.

At least, that's how I read it?





P.s Lukethedork, good on you for having a great attitude mate! I wish more people were like you on this board!

I think what mud80d is trying to say is that spring lift makes the radius arms run downward to the diff instread of nearly horizontal.
When you hit a rock, the impact tends to want to push the diff housing backwards, because of the downward angle of the radius arm in a lifted rig, the force is directed down and back instead of directly backward (or back and up compressing the springs)through the arm to the chassis mount.
I think is more the issue then the arm itself hitting rocks.