Need Pic's of Homemade Ext. Radius Arms

[dieselbronco]

You didn't actually use electrical or plumbing pipe instead of DOM tubing, did you?

What i really did was box in some pvc pipe with 20 gage sheet metal

 

[broncoitis]

What i really did was box in some pvc pipe with 20 gage sheet metal

That should be more than strong enough! LOL!!!

 

[DanWheeler]

I've said this before and I know there are those who disagree with me but in my opinion, extended arms are a waste of time. I built these and ran them for about a year before I decided they were just as useless as stock arms.

The genius of the Duff or Cage design is the second set of bushings that allow them to flex more. I personally believe the amount of leverage added by extended arms is negligible.

I think the $700 for arms that actually flex would be worth it.

 

[DanWheeler]

oh I just read that you are putting this on an 89ish Dana 60 with the short driver's tube. I'm running that axle and I would say there's no way you're going to get wedges on that side. If you do, you'll be welding to cast to steel tube and cast wedge to cast housing and inner C. It would not be fun.

not a lot of room for a cast wedge between the inner C and the housing:

 

[dieselbronco]

i agree that theres not a lot of room but it is doable. i had to trim my housing a little and trim the C's a little but not extremely.



on the other note i have been running my extended arms for several years and i think they work great over the stock arms. i have not ever used the duff/cage arms but do like the design just not the price (over $700) and I'm the build it yourself kinda guy. i like the challange.

 

[dieselbronco]

here is what i did to make room

 

[Tedster100]

These aren't homemade radius arms but here's how you mount them if you are Build A Bronco.com. http://classicbroncos.com/forums/showthread.php?t=200635

According to them you sould be comfortable putting your wife, kids & dog in a rig with these mounts. I'm just sayin'.....

 

[1sicbronconut]

When you weld at the Cast wedge...are you useing Nickle rod..and doing the pre and post heating process?...I have a little experience welding cast pieces...but most all my welding experience has been Mig...very basic I guess..These look like they would be solid and I agree with the rubber C bushings...I would like to (try) johnny joints...alittle expensive for a trial run...

Those wedges are forged not cast and as stated I hope nobody is using pipe because pipe is for poop;D not fab work.

 

[ntsqd]

The leverage increase is easy math. Clearly you haven't done it or you would know that it does increase the leverage significantly.
What may or may not change much with their installation is how much flex is increased. There are too many variables involved to single out just that one and blame it.
And since any sort of wristed arm introduces a degree of freedom to the suspension that a long arm does not have, they can not be directly compared for a valid conclusion.
I really don't care what people decide to run - each option has it's own set of pluses and minuses, but don't slight the other camp with slander.

..... I personally believe the amount of leverage added by extended arms is negligible.

 

[DonaldDouchebag]

These aren't homemade radius arms but here's how you mount them if you are Build A Bronco.com. http://classicbroncos.com/forums/showthread.php?t=200635

According to them you sould be comfortable putting your wife, kids & dog in a rig with these mounts. I'm just sayin'.....

Uggggghhhhhhhhh.

 

[23firefly]

So the way I understand it goes like this:


Run extended stock arms and get a mild manored rig with some possible modest flex on the trail.


Run some form of 3 or 4 link and get maximum amount of trail flex but run the risk of messing with engineered geometry of your rig which can change streetability.

So..........why haven't vendors engineered a 3 or 4 link front Bronco system with a good "disconnectable" anti sway bar? Seems like you would appeal to both camps by combining good trail and street performance.

Not to bring up the Devil but......isn't that the way new jeeps are made?

I mean, if radius arms have flaws then why are we settling? People have built some very innovative radius arms but the bushing seem to be the limiting factor to some extent.

Seems like a 3 or 4 link with a anti sway bar would be the gold standard. If it was well designed and improved the ride over radius arms.

 

[DanWheeler]

The leverage increase is easy math. Clearly you haven't done it or you would know that it does increase the leverage significantly.

I have not done the math. Please enlighten me and show me the math since you claim it is easy and are implying that you have already done it. (with numbers and stuff - I want to see actual math)

Then maybe you can explain why your math makes one side of my axle float even with extended radius arms:

 

[toddz69]

I have not done the math. Please enlighten me and show me the math since you claim it is easy and are implying that you have already done it. (with numbers and stuff - I want to see actual math)

Then maybe you can explain why your math makes one side of my axle float even with extended radius arms:

.

I'm not Thom, but I'll assume with the word leverage that he's refering to a moment being applied to the axle housing by the radius arm by a force acting at the frame connection when the front axle is articulating. That's simply the force x distance. I'm not at home at the moment to measure the length of a stock radius arm but for illustrative purposes, let's assume it's 30" long. With a 6" longer radius arm, that's a 20% increase in the moment (or torque) over stock. With 12" arms, that's a 40% increase in the torque applied to the housing - all other factors being equal.

As to why your axle is floating with the extended radius arms (I'm assuming that side of the frame is on a jackstand), the weight of the axle is not enough to overcome the myriad of forces acting on it to restrain it in that location. If it did drop appreciably in that configuration, you've got much bigger problems.

Todd Z.

 

[DanWheeler]

The whole lever argument would work except for the fact that nobody is pulling on the ends of the radius arms like we pull on a wrench connected to a pipe. The longer the wrench, the more leverage applied but a longer wrench doesn't do you much good when you've got your hands on the pipe itself. While I dont disagree that more leverage is being applied with longer radius arms, I don't think its an accurate comparison. It's all about the twisting of the axle and the C-bushings. The added force means nothing without some calculation of the resistance from the C-bushings.

To the OP - do me a favor: Take some flex measurements before and after your homemade extended radius arms. Backing up an RTI ramp does NOT count. Put your driver's side up on a 1-2' rock and measure distance from tire to flare on both sides. Then re-measure after your extended arms.

 

[HGM]

Just thinking out loud and I'm not a rock crawler, so I have a different perspective.. But, the point behind the extended radius arms (IMO) is to flatten the arc. When the vehicle is moving, as one wheel (or both for that matter) moves, the caster angle will change much less dramatically with extended arms than with stock. So, I relate them more to ride quality and control than "leverage" whatever that has to do with anything.. Also, as for the axle not dropping, your axle and radius arms are acting as a swaybar. The only way to fix that would be to loosen it up somehow, heim's maybe??

 

[toddz69]

Just thinking out loud and I'm not a rock crawler, so I have a different perspective.. But, the point behind the extended radius arms (IMO) is to flatten the arc. When the vehicle is moving, as one wheel (or both for that matter) moves, the caster angle will change much less dramatically with extended arms than with stock. So, I relate them more to ride quality and control than "leverage" whatever that has to do with anything.. /QUOTE]

Bingo. You get it. Less caster change for a given rate of travel. Flatter "angle of attack" to bumps (force vector has smaller vertical component), which helps ride quality, and depending on the style and construction of your arms, you may also gain a bit of caster (my Lars bars give me +1 deg. positive caster.

Todd Z.

 

[6daze]

So the way I understand it goes like this:


Run extended stock arms and get a mild manored rig with some possible modest flex on the trail.


Run some form of 3 or 4 link and get maximum amount of trail flex but run the risk of messing with engineered geometry of your rig which can change streetability.

So..........why haven't vendors engineered a 3 or 4 link front Bronco system with a good "disconnectable" anti sway bar? Seems like you would appeal to both camps by combining good trail and street performance.

Not to bring up the Devil but......isn't that the way new jeeps are made?

I mean, if radius arms have flaws then why are we settling? People have built some very innovative radius arms but the bushing seem to be the limiting factor to some extent.

Seems like a 3 or 4 link with a anti sway bar would be the gold standard. If it was well designed and improved the ride over radius arms.

I went with extended radius arms for simplicity.

The only thing the extended arms required was to add a new mount on the frame.

I was able to use my existing front axle with no mods.

A four/five link would require a lot of mods to my axle or maybe a different one.

I don't need a sway bar. (although I could probably use one, it's not required like a link suspension)

I think it would be difficult for a vendor to develop a kit with the correct steering geometry, accommodate a variety of front axles and 40 year old frames. Then allow for coils or coil over shocks and make it affordable.

Now how many are you going to sell? Not enough to make a profit after that R&D.

Extended arms are simple and work for a lot of people. They will not get you as much travel as a properly set up link suspension.

At least that's my take.

Mark

 

[toddz69]

Run some form of 3 or 4 link and get maximum amount of trail flex but run the risk of messing with engineered geometry of your rig which can change streetability.

So..........why haven't vendors engineered a 3 or 4 link front Bronco system with a good "disconnectable" anti sway bar? Seems like you would appeal to both camps by combining good trail and street performance.

Seems like a 3 or 4 link with a anti sway bar would be the gold standard. If it was well designed and improved the ride over radius arms.

Several reasons: cost, relative market size, and difficulty of installation being three top factors. I was involved with the design and engineering of a 4 link (with panhard bar) system on a friend's early Bronco in the late 90s (I've posted pics in other threads previously). It took a lot of work but we got it to work very well. It flexed like mad and gave up very little in terms of body roll and handling compared to a stock setup. We used King coilovers to suspend the truck. However, the amount of work to install such a system and the cost would be prohibitive to bring it to market.

Todd Z.

 

[gumbydood]

And I believe the wristed axle housing mod eliminates the twisting forces applied by the c-bushings from the radius arms...

 

[ntsqd]

The whole lever argument would work except for the fact that nobody is pulling on the ends of the radius arms like we pull on a wrench connected to a pipe. The longer the wrench, the more leverage applied but a longer wrench doesn't do you much good when you've got your hands on the pipe itself. While I dont disagree that more leverage is being applied with longer radius arms, I don't think its an accurate comparison. It's all about the twisting of the axle and the C-bushings. The added force means nothing without some calculation of the resistance from the C-bushings.

The reason that your long arm picture shows what it does is because there is no force there. The axle housing is a torsion bar and the radius arms are levers. For the levers to twist the housing there has to be an articulating force, which isn't present in your picture. You say it yourself with "except for the fact that nobody is pulling on the ends of the radius arms." Lift on the LH knuckle with a floor jack or fork lift and watch what happens. Now you've got an articulating force present.

Look at this picture and tell me which extreme of the setting range will yield the softest sway bar and which will yield the stiffest sway bar:

The radius arms and axle housing are no different, but just like the sway bar there has to a be force present to do anything.

Some might say "yeah, but do that same thing with a wristed arm or rotating housing and that side will droop a little more." It might, that is the degree of freedom that I was talking about. This is not a valid comparison since a hinge has been introduced into the system. They are apples and oranges and can't be directly compared.

If wheel travel and handling at speed is your goal then long arms are the better choice. If articulation is your goal then a wristed/rotating approach is the better choice.