3 link vs radius arms

[JeepFreak21]

if i remember correctly, he had a massive failure (I think the upper link broke) and it bent the lowers up. rather than re-making the links he added the plate to regain some strength

Yup.
Billy

 

[Jes]

if i remember correctly, he had a massive failure (I think the upper link broke) and it bent the lowers up. rather than re-making the links he added the plate to regain some strength

That is totally retarded.

 

[XJZ]

That is totally retarded.

Hard braking + curved lower arms = SNAP!!

How could you not see that coming?

Gussets seem like such a Band-Aid. Wouldn't it just be easier to cut the joints off and get some new tube?

 

[Jeff 98XJ WI]

In my opinion, Wandering Willys setup used bent arms to clear the "frame" and allow the arms to bolt to the crossmember closer to the frame as compared to the URF design which uses straight arms, but mounts them closer to the middle of the Jeep to clear the frame. Matt also is using the stock lca mounts for his upper wishbone, so the lower arms must clear the stock lca mounts. The arms were also bent for ground clearance. I'm not sure why he added the plate, but I imagine he ended up with some bending of the lower links, so he reinforced them with plate. Jeff

 

[Jes]

So, bend the arms to gain ground clearance then add the plate to lose ground clearance.
Dumb.

 

[tealcherokee]

typically when you're talking about an XJ with a 3-link front, that means 3 basically parallel links and a panhard bar, since there are very, very few people running full-hydro on XJs. That picture is a wishbone, triangulated 3 link. If you're going to have a steering box and draglink, the best suspension you can run is a 3 link with panhard, the URF version is superb, search for that.

thank you!!!! i hate when ppl confuse 3 links w/ other suspension links

 

[cyrus]

Please excuse my questions and statements here and correct or in form me otherwise if I am not relizing something. I do understand the concept of radially twisting the axle under extreme flex using a radius arm or "hard arm" style control arm. But if you were to remove, or at least remove one end of one of the two short "arms" on connecting the upper axle mount to the lower cotrol arm or radius arm. Would that not result in basiclly the same manerisms, as far as flex goes, as a true three link? Keepinf in mind this probably wouldnt be wise to run on the road, nut as a trail only rig, this should work, right?

 

[hackedxj]

Please excuse my questions and statements here and correct or in form me otherwise if I am not relizing something. I do understand the concept of radially twisting the axle under extreme flex using a radius arm or "hard arm" style control arm. But if you were to remove, or at least remove one end of one of the two short "arms" on connecting the upper axle mount to the lower cotrol arm or radius arm. Would that not result in basiclly the same manerisms, as far as flex goes, as a true three link? Keepinf in mind this probably wouldnt be wise to run on the road, nut as a trail only rig, this should work, right?

I've driven both and they definately don't have the same manerisms. Someone here can probably explain why better than I can.

 

[cyrus]

I've driven both and they definately don't have the same manerisms. Someone here can probably explain why better than I can.

What drove differnent about them?
I am in the middle of a long radius-arm build and can and will change my direction if I am convinced that the way I am going is wrong and/or not safe. I am looking for insite, and opinions on both the three link and radius arm. I have found plenty of opinions here, which is good, but not any real discriptive reasons. I can still switch to the three link if needed, but I want to know driving caracteristics.

 

[zith]

Figured I'd tack on a question of my own since I'm considering building a longarm setup and trying to decide which route to go.

A friend in my club swears by his 3-link, and I'll admit it flexes like mad. What's been confusing me is link separation at the frame side. He has all 3 arms pivot on the same line, making sure that the pinion angle is always pointing to the TC. Wouldn't this behave almost exactly like a radius arm, except have not have that bind (more flex)?

 

[BrettM]

What drove differnent about them?
I am in the middle of a long radius-arm build and can and will change my direction if I am convinced that the way I am going is wrong and/or not safe. I am looking for insite, and opinions on both the three link and radius arm. I have found plenty of opinions here, which is good, but not any real discriptive reasons. I can still switch to the three link if needed, but I want to know driving caracteristics.

I would much rather have radius arms on both sides than on one side and the other with a single lower. The small loss in flex would be worth having even suspension characteristics. When you run only one upper (or wristed arms for Ford radius arms) all the anti-dive properties are transferred to only one side of the vehicle, meaning the suspension and traction will behave very differently with one side stuffed vs. the other side stuffed.

Better is a parallel 3 link (w/ panhard). Make the uppers roughly 75% of the lowers length, and the seperation at the frame roughly 75% of the seperation at the axle and it will function pretty well. If you want to get more complicated you can use the 4 link calculator (found on the Pirate board in Triaged's sig) and figure out the exact anti-dive.

 

[BrettM]

Figured I'd tack on a question of my own since I'm considering building a longarm setup and trying to decide which route to go.

A friend in my club swears by his 3-link, and I'll admit it flexes like mad. What's been confusing me is link separation at the frame side. He has all 3 arms pivot on the same line, making sure that the pinion angle is always pointing to the TC. Wouldn't this behave almost exactly like a radius arm, except have not have that bind (more flex)?

if the uppers and lowers are very parallel (same seperation at frame and axle) then it will be fairly neutral (100%) in anti-dive.

if the uppers and lowers have little to no seperation at the frame side they will have the same anti-dive characteristics of a radius arm.

 

[cyrus]

I would much rather have radius arms on both sides than on one side and the other with a single lower. The small loss in flex would be worth having even suspension characteristics. When you run only one upper (or wristed arms for Ford radius arms) all the anti-dive properties are transferred to only one side of the vehicle, meaning the suspension and traction will behave very differently with one side stuffed vs. the other side stuffed.

Better is a parallel 3 link (w/ panhard). Make the uppers roughly 75% of the lowers length, and the seperation at the frame roughly 75% of the seperation at the axle and it will function pretty well. If you want to get more complicated you can use the 4 link calculator (found on the Pirate board in Triaged's sig) and figure out the exact anti-dive.

Thanks for the insite, that is the best explination I have gotten yet.

 

[XJoachim]

I would much rather have radius arms on both sides than on one side and the other with a single lower. The small loss in flex would be worth having even suspension characteristics. When you run only one upper (or wristed arms for Ford radius arms) all the anti-dive properties are transferred to only one side of the vehicle, meaning the suspension and traction will behave very differently with one side stuffed vs. the other side stuffed.

I run this setup and i'm really happy with it. The downside with 2 upper arms connected if you have a 60 in front with 1/2" tubes is that you will have a big amount of bind in your suspension because this axle will not flex like a D30. One thing has to give and it will not be the axle. You will break control arms, rip off mounts or you limit flex with limiting straps.

It's simply not possible to run a 4-link with panhard bar and a stout axle like a built 60 without breaking anything if you're achieving full flex of your suspension. Had to learn it the hard way myself, broke 3 control arms and ripped off 2 mounts until i chose to ditch 1 upper arm. Since then no more problems. :wave:

 

[bj-666]

I run this setup and i'm really happy with it. The downside with 2 upper arms connected if you have a 60 in front with 1/2" tubes is that you will have a big amount of bind in your suspension because this axle will not flex like a D30. One thing has to give and it will not be the axle. You will break control arms, rip off mounts or you limit flex with limiting straps.

It's simply not possible to run a 4-link with panhard bar and a stout axle like a built 60 without breaking anything if you're achieving full flex of your suspension. Had to learn it the hard way myself, broke 3 control arms and ripped off 2 mounts until i chose to ditch 1 upper arm. Since then no more problems. :wave:

i don't agree there has to be something on every axle that limits the droop of the axle to say that with a 60 you will break more mounts is kinda a dumb truth if you have no bind and nothing to hold the axle up to the vehicle it will droop till it is back by the rear wheels. that is the reason for limiting straps to stop the axle from drooping so far that is hurts parts of the suspension in my mind everyone should be running straps because if it isn't a strap limiting droop it is brakelines shocks etc. all are pieces of the suspension that should not have to handle that load. (this only applys to linked suspension)

 

[BrettM]

I run this setup and i'm really happy with it. The downside with 2 upper arms connected if you have a 60 in front with 1/2" tubes is that you will have a big amount of bind in your suspension because this axle will not flex like a D30. One thing has to give and it will not be the axle. You will break control arms, rip off mounts or you limit flex with limiting straps.

It's simply not possible to run a 4-link with panhard bar and a stout axle like a built 60 without breaking anything if you're achieving full flex of your suspension. Had to learn it the hard way myself, broke 3 control arms and ripped off 2 mounts until i chose to ditch 1 upper arm. Since then no more problems. :wave:

yes, with 2 radius arms, something has to give, that's what bushings are for. if you're going to the hassle of putting a 60 in the front of an XJ though, I can't imagine why not spend the small amount of extra work to do a 3 link w/ panhard rather than running a single radius arm.

 

[XJoachim]

With the second upper arm connected and running rubber bushings on all control arms i had a slight wobble on the front. Since every thing else was new i started replacing the rubber bushings with RE joints on the frame side and since the axle side bushings were destroyed i replaced them too. The uppers remained unchanged and the wobble was still there.

The next time out i heard a big bang and the drivers side upper mount was ripped off the pumpkin so i simply removed it. On the way home i noticed that there was no wobble any more. Since i went to hydro assist i don't even run a steering stabilizer any more.

I replaced the bushings of the remaining upper with polys to limit axle movement and i will in the future replace them with RE joints too.

BTW, i see no advantage to have a 3-link (1 upper arm connected to the frame) instead of running a radius style long arm on one side and a single lower long arm on the other side.

 

[BrettM]

BTW, i see no advantage to have a 3-link (1 upper arm connected to the frame) instead of running a radius style long arm on one side and a single lower long arm on the other side.

that's because you know nothing about suspension geometry

 

[XJoachim]

Why don't you teach me? :worship: I can not see any advantage, caster change doesn't affect me off road but my pinion angle doesn't change like in a 3-link configuration. I'm already at the limits of my driveshaft angles and any dive of the pinion would result in driveshaft breakage.

 

[BrettM]

so you would have to turn the knuckles if you wanted to run a superior suspension, not that big of a deal in the grand scheme of things.

radius arms have very little control of anti-dive (like anti-squat, but for the front) and generally have far too much. a 3 link w/ panhard allows a huge breadth of anti-dive possibilities.

of course the few pictures I remember seeing of your rig aren't on steep rock climbs, which is where good anti-dive numbers are most beneficial.