Dan Wheeler's Radius Arm Build Thread

[DanWheeler]

Fine job Dan !! The only thing I see that could cause a problem is the shock mount being mounted off center as it could cause a twisting moment in the arm itself.

I have F250 shock mounts which extend out away from the frame so putting the shock mounts outside the arm a bit straightens the shock out vertically. Then when the axle at full droop on that side there will be less stress put on the shock bushings.

 

[bronko69er]

I have F250 shock mounts which extend out away from the frame so putting the shock mounts outside the arm a bit straightens the shock out vertically. Then when the axle at full droop on that side there will be less stress put on the shock bushings.

He's saying that the resistive force applied by the shock to the arm will tend to make the arm wan to twist since that force is not passing through the center of the arm.

I dont really see this as being a huge issue as I feel that C-bushing can handle that torque.

 

[67Stallion]

Good job! I would like to try that myself one of these days, i think i will go with 6 inches longer arms.

 

[DanWheeler]

He's saying that the resistive force applied by the shock to the arm will tend to make the arm wan to twist since that force is not passing through the center of the arm.

I dont really see this as being a huge issue as I feel that C-bushing can handle that torque.

oh, yeah i see. yeah i suppose its possible but i agree, the amount of leverage created by introducing a fulcrum 1.5" out is pretty small compared to the c-bushings

 

[broncow72]

I'm finally free!

Well i still have to actually install them but hopefully the hardwork is over. I dont know why it took so long to make these. They look simple.

You screwed the pooch there... you bent the arms the wrong way. The bends should go inward. Start all over now.;D

 

[carter2772]

The Duff long arms have the shock mount on the side as well, and you are able to run dual shocks in that same location. They are designed for the c bushings, so i dont think you will have any problem, pretty sure cage is the same way.

Nice work!

 

[DanWheeler]

The Duff long arms have the shock mount on the side as well, and you are able to run dual shocks in that same location. They are designed for the c bushings, so i dont think you will have any problem, pretty sure cage is the same way.

Nice work!

i notice the shock mounts on the duff arms are oriented 90 degrees to stock.

i thought about doing this and I still could with the square tube I would just need to drill perpendicular to the existing holes.

Anyone have thoughts about which direction is best? I would expect there to be more forward to backward movement of the axle due to it rotating in an arc around the radius arm pivot point.

how does that compare to the movement left to right caused by the panhard? which is more?

anyone have pictures of some shock mounts that rotate both direction? i've heard of people making shock mount u-joints that can flex both ways.

i'm not sure if this is much of a concern since I dont think the shocks bushings are really going to prevent articulation.

 

[broncow72]

i notice the shock mounts on the duff arms are oriented 90 degrees to stock.

i thought about doing this and I still could with the square tube I would just need to drill perpendicular to the existing holes.

Anyone have thoughts about which direction is best? I would expect there to be more forward to backward movement of the axle due to it rotating in an arc around the radius arm pivot point.

how does that compare to the movement left to right caused by the panhard? which is more?

anyone have pictures of some shock mounts that rotate both direction? i've heard of people making shock mount u-joints that can flex both ways.

i'm not sure if this is much of a concern since I dont think the shocks bushings are really going to prevent articulation.

The bushings won't limit articulation but when the shock eye and mount bracket make contact you may have an issue with bending the shock shafts. I think there may be a reason Duff's mounts are 90 degrees out.

 

[DanWheeler]

got things pretty much finished up tonight

no problem with the shock mount clearance:

shock alignment is perfect:

the new mounts are nice:

aaaaaaaaaaaaaand the new arms are pretty much the same as the old ones:

my tie-rod would normally be parallel with my bumper but after the new arms are installed you can see a very slight difference in angle between the tie-rod and the bumper.

My analysis:
Total waste of time.

Unless you incorporate some element of the cage or duff design with the second set of bushings, you simply have not solved the C-bushing bind problem.

so, it's on to the next thing which will probably be something like a single/simple link on the passenger side and a 2-point link on the driver's side. Or i'll just pony up for the cage arms.

 

[DanWheeler]

i know i'm probably going to get a lot of people saying give it a chance but here's my thinking. If I can't jack up one side of the front end a few inches without the entire truck leaning to one side then what good is it going to be on the trail on an incline when there is no weight to assist in twisting the C-bushings? When you're going up a hill, all your weight shifts towards the rear axle. Your front end becomes almost weightless like you're doing a wheelie. I've experienced this while at a 45 degree angle and I hit a rock on the passenger side and instead of that wheel absorbing the rock and flexing upwards into the wheel well, it caused the entire front end to go upwards with the driver's side tire completely in the air. The axle wouldn't flex because there wasn't enough weight up front to counteract the stiffness of the C-bushings. I have some video of my truck I may post to show this phenomenom.

Bottom line - the flex doesn't come easily enough with these c-bushings to be useful. Sure if I back up an incline ramp I might get some decent results because the weight transfer is towards the front but how often do you go backing up the trails?

 

[ken75ranger]

From your last post your starting to see the light.
I had to have the guys that designed my suspension showed me the same thing.
The natural bind of a radius arm is good and bad. Like you say once the weight is transferred back it's tough for the front end to droop. A rubber c-bushing would help flex but how long would they last on a wheeling rig?
That same stiffness is also acting as your sway bar. Lose that and you'll need a swaybar for highway driving.
Going by your fab skills in this thread your ready to bite the bullet and just 3 or 4 link it.

 

[Mark]

IMO the best flex setup is to use a WAH with BC's adjustable caster arms.

Longarms, while effective, simply provide more leverage on the C bushings.

 

[bronko69er]

i know i'm probably going to get a lot of people saying give it a chance but here's my thinking. If I can't jack up one side of the front end a few inches without the entire truck leaning to one side then what good is it going to be on the trail on an incline when there is no weight to assist in twisting the C-bushings? When you're going up a hill, all your weight shifts towards the rear axle. Your front end becomes almost weightless like you're doing a wheelie. I've experienced this while at a 45 degree angle and I hit a rock on the passenger side and instead of that wheel absorbing the rock and flexing upwards into the wheel well, it caused the entire front end to go upwards with the driver's side tire completely in the air. The axle wouldn't flex because there wasn't enough weight up front to counteract the stiffness of the C-bushings. I have some video of my truck I may post to show this phenomenom.

Bottom line - the flex doesn't come easily enough with these c-bushings to be useful. Sure if I back up an incline ramp I might get some decent results because the weight transfer is towards the front but how often do you go backing up the trails?

It seems like you are forgetting that there will always be springs that need to be compressed in order for "articulation" to occur. Even with a 4 link (and no articulation bind), when that end is uphill or virtually unweighted, there is little weight to compress the spring and induce "articulation". There is no way around this other than a suck down winch.

By making your arms longer you have reduced the bind effect of the C-bushings.


You're right, my comment: "Don't be so quick to shoot down your work."

Example of the difference in articulation based on weighting (same setup):

 

[bronko69er]

Longarms, while effective, simply provide more leverage on the C bushings.

Yes, but they also reduce the amount of induced flexure on the bushings to achieve the same articulation.

 

[DanWheeler]

if a basically stock J**P can do it, so can I... or at least I want to be able to.

I wont be satisfied until my passenger tire touches the top of the fender well and I can have a picnic on top of my driver side tire.

 

[HOJO]

Im the same way here is a pic of my tj crawler and I hope to get my bronco do do this someday

 

[blazinchuck]

i may have missed it somewhere..but what coils are you using? im using cage coils...and they have been the best ive used to date. my 77 has WH 5.5" rock crawler coils(soon installing the cage 3.5's)also has duff arms. and its not flexy half as mush as my FBG w/42's,ton,cage arms and coils. so the cage coils are going in next couple weeks.


also the pic ya posted of the TJ is not the same as you simply jack one side of yours up...there are other factors at play in that pic, just like Bronk69er is explaining

 

[HOJO]

Very true the will always be carry or rebound on the unweighted side ..unless like he said sucking the suspension down like they do in competetion to get the vehicle itself to work and not go up when you dont want it to...