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Discussion Starter · #1 ·
I'm gonna make the traditional Y shaped radius arms. Looking at 36" long for the lower, will 20" be too long for the uppers with approximately 8" of vertical seperation at the axle? I've searched and only found mention of the importance of vertical seperation and running with only one upper. Nothing about the effects of a longer than normal upper. Plan on running uppers on both arms if it means anything. Thanks.
 

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Running 2 uppers will be fine if you only want the axle to go up and down. If you had planed on it articulating as well it will only articulate by deflecting something.

Time to do a search and start over....

Try searching for degree of freedom, torque lean, etc...
 

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Triaged said:
Running 2 uppers will be fine if you only want the axle to go up and down. If you had planed on it articulating as well it will only articulate by deflecting something.

Time to do a search and start over....

Try searching for degree of freedom, torque lean, etc...

blah blah blah radius arms don't flex blah blah blah..... thats pretty much what this post adds up guys reply adds up to and its in uneducated comment anyway.

On topic the longer the upper are the better in my point of view. A longer upper arm means less of an angle between the upper and lower. This means the upper will be applying less bending force into the lower.

p.s. radius arms setups can flex well look at fords and Rubicon Express Long Arm kits....
 

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Discussion Starter · #4 ·
Yes, I know that removing one of the uppers will allow more flex, should be on the non-pumpkin side to retain pinion angle, and will dive to the side where the upper is removed. I plan on 2 uppers and maybe removing the passenger upper, drivers diff, if I need more flex offroad. I thought the flex is everything craze was over? I never saw this issue covered and all the pics I've seen, i.e. RE longarm, were shorter uppers than I'm gonna run. I figured it would distribute force better, but was wondering about the twisting. Thanks for the responces guys.
 

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Jamus2 said:
I'm gonna make the traditional Y shaped radius arms. Looking at 36" long for the lower, will 20" be too long for the uppers with approximately 8" of vertical seperation at the axle? I've searched and only found mention of the importance of vertical seperation and running with only one upper. QUOTE]

How much vertical seperation is required on a standard radius arm set up?(assuming someone uses the same Y shaped arm on each side)
Seems to me from the looks of it ford radius arms don't have that much seperation on them. :confused:
 

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The closer you can get the fork of a Y link the stronger it will be. Bending is the weakist way to load something. The shorter the Y is the more the bending. If you make it into a V link (both sided the same length) the only bending will be in the rod end (also a bad way to load a rod end).
 

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Triaged said:
The closer you can get the fork of a Y link the stronger it will be. Bending is the weakist way to load something. The shorter the Y is the more the bending. If you make it into a V link (both sided the same length) the only bending will be in the rod end (also a bad way to load a rod end).
I think your mistaken the lesser angle on the arms will better align the rod ends with the rotational forces of the differential.

ANyways I don't think you need to over think this, it seems alot of times its better to just overbuild for a trail rig then try to over engineer.
 

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NE-RokToy said:
Your first mistake :flipoff2:

NE-RokToy said:
the lesser angle on the arms will better align the rod ends with the rotational forces of the differential.
Moving around the back end of the bars won't change the load in the rod ends one bit unless you are talking about making the whole thing longer (that will lower the load on the rod end and allow for more flex). More seperation at the axle will lead to less load on the forward bushings and less flex.

NE-RokToy said:
ANyways I don't think you need to over think this, it seems alot of times its better to just overbuild for a trail rig then try to over engineer.
Maybe easier to overbuild but almost never better.
 

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a better idea would be to copy a LandRover radius arm design
the bushings do not fight "articulation"/roll as much
 

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Triaged said:
Moving around the back end of the bars won't change the load in the rod ends one bit unless you are talking about making the whole thing longer (that will lower the load on the rod end and allow for more flex). More seperation at the axle will lead to less load on the forward bushings and less flex.
I was talking about the angle of the upper and how a flatter angle will place the load inline with the rod end/bushing which I think is a better way to load something.

ANd as far as my overbuilding concept the reason I've mentioned it is radius arms are fairly common and reliable so you don't need to over think the design, just insure you build them very sturdy.
 
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