new adjustable radius arm design for those with D44

[351wExplorer]

i came up with this after looking at a buddies traction bar on his camaro.... i adapted that design to fit me application..
I think it would be very beneficial to be able to adjust the castor with somthing different then the c bushings. This model i came up with is very heavy duty, but keep in mind this is purely a prototype... I mean i dont know how well this would really work so i would like all of you fabrication and suspension geometry gurus to help me perfect this.

feel free to comment or ask any questions


I just realized that it isnt a circle in the middle, but it is a wedge, i want to keep the stock coil bucket up front and still use the c-bushings so this will just bolt into place

 

[gijoecam]

i came up with this after looking at a buddies traction bar on his camaro.... i adapted that design to fit me application..
I think it would be very beneficial to be able to adjust the castor with somthing different then the c bushings. This model i came up with is very heavy duty, but keep in mind this is purely a prototype... I mean i dont know how well this would really work so i would like all of you fabrication and suspension geometry gurus to help me perfect this.

feel free to comment or ask any questions


I just realized that it isnt a circle in the middle, but it is a wedge, i want to keep the stock coil bucket up front and still use the c-bushings so this will just bolt into place

That should work to stabilize the axle fore and aft, but what type of lateral stabilizer will you be using?

-Joe

 

[351wExplorer]

what do you mean lateral stabalizer... i already have a track bar on my d44, these would just replace the radius arms, everything else is done

 

[gijoecam]

Gotcha.... something to stabilize the axle side-to-side. A trac bar certainly fills the bill. I wasn't sure what you had in place already, that's all.

It's a good idea (the arms). Make sure the heim joints are heavy duty. Also, I'm not quite sure from the sketch what you're looking at on the axle end for being able to adjust them.... If you're thinking eccentric heads on the bolts (like they use on the aftermarket control arms to adjust the caster) I'd avoid it. But, if you're looking at using heim joints on both ends, adjustment becomes a piece of cake! Remove two bolts, swing the arm down, spin two rod ends out or in as necessary, swing the arm up and put the two bolts back in. (of course the frame has to be supported to stop the axle from squirting out the front end)

The only thing that always worries me about using heim joints or any spherical bearing is that they're only designed to take tensile and compressive loads. They don't like shear loads. In ordinary operation, they shouldn't see any shear loads, but if you happen to land on one of the arms, with the weight of the vehicle on the front end, the rod ends end up in shear, their weakest direction. Always carry a few spares if you can.

So, in short, if you use 'em, over-size the snot out of 'em and you should be good to go.

-Joe

 

[gijoecam]

Just another thought.... the piece you show as being machined from steel could also be done (and be just as strong) if made from a weldment. 1/4" plate stock cut and ground to the proper shape and properly welded wouldn't be too difficult to do, and could be lighter and trail-fix-able should it ever get mangled, where the machined piece could be a little more difficult to get back together.

Just a thought....

-Joe

 

[351wExplorer]

my brother can machinge it... he works in a machine shop... but im not dead set on having the machined, i might have somthing welded up. The adjustments on the axle end of the arm would be, well i cant think what they are called. The are like hiems joints, but the dont flex side to side, they are just flat and threaded..

 

[Josh]

Why not just chop the end of the radius arm off and use it in conjuction with the rear part of your design? I have been trying to come up with a design for the TTB radius arms. I was thinking in the top tube of the radius arm you could have a section with threaded sleaves on both ends, a stud coming out of the part that connects to the axle maybe welded to a housing for a pivot bushing and another stud coming out of the rearpart of the upper tubing. The lower tube would just go straight to the barcket on the axle with a pivot bushing as well. Does that seem logical?

 

[Josh]

Below is a rough idea on what I was thinking for TTB.

 

[351wExplorer]

you had to get all fancy with the ruler didnt you...haha looks good. Im not sure but i think it is essentially the same as what i was thinking but with much more adjustment

 

[351wExplorer]

after looking at it again, dont you think the threaded rod would be the weakest point?

 

[Josh]

Yes your drawing inspired me, but I would think if you used 1" studs you would be OK. The only reason I thought of this was you would not have to remove/unbolt the radius arm to adjust the castor, simply twist the section between the studs. The drawing is out of proportion, I don't think you need a whole lot of adjustment. I used a ruler(Actualy a CD case) because I can't draw worth a crap. I would have strated this already, but my buddy talked me into throwing away my old radius arms while cleaning the garage one day. If I ever do this you can bet I will take it out and punish it.

 

[410Fortune]

Looks REALLY similar to a rubicon express Jeep arm

 

[gijoecam]

Below is a rough idea on what I was thinking for TTB.

That would work, but should you happen to take a rock hit upwards right there in the middle of the radius arm (not uncommon around large rocks) the lower tube can bend right in the middle. The advantage to reinforcing the center with a web of some sort is that you get infinitely more rigid tubes.

Another way to think of it.... Look at a new engineered floor joist.... 2x4 on top and bottom with the OSB in the middle shaped like an I-beam. Take the 'web' out of the middle (the OSB) and the top and bottom board are very flexible (relatively speaking). Stick the web in the middle and they become 100 times stronger.

The same principle can be applied here.... stick a web in the middle and yes, adjusting the caster becomes a bit more difficult, but you gain TONS of strength. I would do it that way for two reasons: First, the shear strength increases dramatically. Second, you'll likely only ever need to adjust the caster once. Once it's set, barring a major catastrophic failure, there shouldn't be much need to adjust it again, so having it 'convenient' to change isn't a big necessity in my book.

Good idea still....

-Joe

 

[gijoecam]

Another thought: The arm will be significantly stronger in compression too.... think about the tire bumping up against a parking block (or log, or boulder, high curb, etc). When you bump it, the force of the vehicle pushing against the wheel puts the radius arm in compression. If you have any trail damage (kink or dent in the tube) the tube can collapse very easily. The flat plate between the two tubes will prevent this in a MAJOR way.

-Joe

 

[Josh]

That would work, but should you happen to take a rock hit upwards right there in the middle of the radius arm (not uncommon around large rocks) the lower tube can bend right in the middle. The advantage to reinforcing the center with a web of some sort is that you get infinitely more rigid tubes.

OK OK here comes the common sense. LOL. I do not have a lot of hardcore trail experience like some of you guys, but I am a dreamer. Better to learn the lessons on paper then on the trail. Its good to have this forum to keep things in perspective.

yes, adjusting the caster becomes a bit more difficult, but you gain TONS of strength. I would do it that way for two reasons: First, the shear strength increases dramatically. Second, you'll likely only ever need to adjust the caster once.

Point well taken I guess there wouldn't be a need to adjust it but once or twice in the vehicles lifetime. I wish I had a welder, plasma cutter and some other goddies, I would prbably never leave the garage.

 

[Josh]

Looks REALLY similar to a rubicon express Jeep arm

It is the same concept. I was just trying to keep all the work in the radius arm and not have to worry about welding a bracket to the axle beam. Not only am I a dreamer but I'm lazy.

 

[Josh]

Well back to the subject of strength. Will a MIG welder produce strong enough welds to do something like this? If so, are there any benifits between using flux core or gas. My buddy told me that stick is the stronger than MIG, but I think MIG is a little easier to use.

 

[rookieshooter]

Josh on my RA I used a 220 stick. My 120 Hobart could not penetrate as well as the stick. I've used both flux core and non flux. Majority of the time I'm outside and don't have a wind shild to keep the argon gas around the weld anyway so i use flux core a lot. I just clean up the splatter. There are better welders them me on this site and they might answere also.

I love my mig and it is very easy to use. Where as the stick you have to constantly feed the rod to the work. I really think that you need both if your going to get serious about all this.

 

[james t]

My buddy told me that stick is the stronger than MIG, but I think MIG is a little easier to use.

Too general of a statement- one is not "stronger" than the other. If its getting decent penetration, its all the same. If the part is designed right, fitted right, and then welded right, the part itself will break before the weld will.

 

[Josh]

So how do you know if you are getting good penetration? That just sounds dirty

Rookie,
Your welds lok pretty good to me