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Unread 07-27-2010, 09:47 AM   #31
mrblaine
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Originally Posted by Peterpsc View Post
I'll enjoy this thread.
Maybe, maybe not. I'm not posting any more updates or pictures until someone tells me about radius rod front suspensions.

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Unread 07-27-2010, 09:57 AM   #32
Robert J. yates
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LOL Blaine..... I guess the title was not enough on it's own to incite some difference of opinion.

As for the tank.... Some of you should cruise the for sale boards more often. I gave someone a smoking deal on it to get it out of my hair.
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Unread 07-27-2010, 10:03 AM   #33
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From my limited research, radius rod suspensions are similar to radius arm setups but don't rely on such a large bind factor at the wrist. There is one link mounting point on the frame and two on the axle (upper and lower).

That's all I know. I could go into the why's but I'm not sure I'd be right. As to why it would be a good thing on a tall TJ......uuuhhh, it allows for a flatter link angle? That's assuming it's a GOOD thing. From my research with radius arms, it's not.
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Last edited by Imped; 07-27-2010 at 10:16 AM..
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Unread 07-27-2010, 10:12 AM   #34
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Originally Posted by mrblaine View Post
Maybe, maybe not. I'm not posting any more updates or pictures until someone tells me about radius rod front suspensions.
There is no upper mount to the frame, so they would unload horribly on any kind of incline, and a lifted TJ, with its center of gravity higher than most, it would make the problem worse... Those were just my findings

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Unread 07-27-2010, 10:15 AM   #35
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Why does the name Robert Yates sound so familiar?
Brock Yates was the Editor of Car & Driver for a long time and was a pit reporter for CBS back in the Dale Sr. heydays of the '80s. Maybe Robert is related?
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Unread 07-27-2010, 10:16 AM   #36
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Originally Posted by mrblaine View Post
Maybe, maybe not. I'm not posting any more updates or pictures until someone tells me about radius rod front suspensions.
Am I understanding correctly that its part "swaybar" - part "trac-bar"? In this case, would it be used for further stability on your TJ?
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Unread 07-27-2010, 10:18 AM   #37
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Originally Posted by RikatyJeep View Post
There is no upper mount to the frame, so they would unload horribly on any kind of incline, and a lifted TJ, with its center of gravity higher than most, it would make the problem worse... Those were just my findings
Not only does it unload pretty badly, but they are very difficult to adjust given that the front axle on a TJ has mild triangulation between the upper and lower arms.

A radius rod in it's pure form has no ability to change the angle at the chassis pivot, so as you adjust caster or wheelbase slightly, the links have to be distorted to line up with the mounts.
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Unread 07-27-2010, 10:22 AM   #38
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Am I understanding correctly that its part "swaybar" - part "trac-bar"? In this case, would it be used for further stability on your TJ?
No, go to the link and arrow down to the front radius rod section to give an idea of what it mostly looks like and the concept.

Zig's Street Rod - Suspension - Front Components
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Unread 07-27-2010, 10:23 AM   #39
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Originally Posted by mrblaine View Post
Here's your challenge for the day. Learn what radius rod suspension is and why it would or would not be a good thing on the front of an over height TJ.
why do I get picked on today

I'm assuming you're refering to radius arm suspension, like some aftermarket's like to run, or the old F150/Broncos.

Well, on a tall TJ, I would expect weird pinion/caster changes during flex & suspension travel since the housing remains fixed. so instead of the pinion moving with the two unequal radii, you'd get one radius. i suspect that would lead to rather interesting dive/anti-dive properties in the front end...making uphill climbing on rocks result in major unloading without a suckdown winch.

how close am I?

EDIT: ***aww you already answered as I was typing***
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Unread 07-27-2010, 10:25 AM   #40
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Well damn. I put way too much thought into something once again. I already knew the answer.
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Unread 07-27-2010, 10:26 AM   #41
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Originally Posted by Unlimited04 View Post
why do I get picked on today

I'm assuming you're refering to radius arm suspension, like some aftermarket's like to run, or the old F150/Broncos.

Well, on a tall TJ, I would expect weird pinion/caster changes during flex & suspension travel since the housing remains fixed. so instead of the pinion moving with the two unequal radii, you'd get one radii. i suspect that would lead to rather interesting dive/anti-dive properties in the front end...making uphill climbing on rocks result in major unloading without a suckdown winch.

how close am I?
Go to the link I posted and get a clarified view of what we're dealing with. It's an adjustable radius rod, not radius arm. Only make the links adjustable at both ends and now you have a triangle that has offset planes.
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Unread 07-27-2010, 10:28 AM   #42
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Originally Posted by mrblaine View Post
Not only does it unload pretty badly, but they are very difficult to adjust given that the front axle on a TJ has mild triangulation between the upper and lower arms.

A radius rod in it's pure form has no ability to change the angle at the chassis pivot, so as you adjust caster or wheelbase slightly, the links have to be distorted to line up with the mounts.
Four Wheeler did an install on an 07 JK, and they seem to like it, maybe this is different that what you're talking about. Maybe with a longer wheel based JK it may not be so bad.

2007 Jeep Wrangler Rubicon Suspension - Four Wheeler Magazine

**EDIT** Wrong type, more of a radius arm like Unlimited04 was talking about
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Unread 07-27-2010, 10:32 AM   #43
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Originally Posted by mrblaine View Post
Go to the link I posted and get a clarified view of what we're dealing with. It's an adjustable radius rod, not radius arm. Only make the links adjustable at both ends and now you have a triangle that has offset planes.
ohhh i think i see now...two arms of near equal length that are fixed to each other at one end, which mounts to the frame, and two adjustable ends at the axle? vs the radius arm, which has one long arm and one short arm, with the short arm mounted to the axle and center of the long arm...or i guess a "wristed" radius arm?
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Unread 07-27-2010, 10:35 AM   #44
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ohhh i think i see now...two arms of near equal length that are fixed to each other at one end, which mounts to the frame, and two adjustable ends at the axle? vs the radius arm, which has one long arm and one short arm, with the short arm mounted to the axle and center of the long arm...or i guess a "wristed" radius arm?


Yes, radius rod, not wristed radius arm, which by the way, the article fairly well screwed the pooch on their reasons to install one.
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Unread 07-27-2010, 10:40 AM   #45
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Originally Posted by mrblaine View Post
Yes, radius rod, not wristed radius arm, which by the way, the article fairly well screwed the pooch on their reasons to install one.
on that ford roadster example, i could see lots of torsional effects since the upper and lower mounts want to change planes under flex with the radii the axle housing travels in (with respect to each other - three mounting points wouldn't remain in the same plane). i could see how it would work on a roadster where the I-beam doesn't have a lot of travel, but the torsion of off-road suspension would place lots of stress on the union between the two arms and the axle mounts.

How close was that?
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