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Why not run a 4 link up front?

Depending on your intended use... none at all
A four link has some inherent "bind" in its design: the control arms fight each other when the suspension tries to flex past a certain point. The factory rubber bushings do a good job of distorting to keep good flex, ride quality and durability.
The harder the joint, the less "squish" you get, the more binding you may experience. Of course, other factors can come in to play before the arms cause bind at all.
A 3 link doesn't have as much inherent bind, though some will say that it is weaker than a 4 link and not as well suited to go-fast applications. Many rock crawlers seem to prefer the 3 link setup.
Does that clarify?
 
running a long arm kit, wether a 3 link or 4 link or radius arm, adds flex. If you choose to keep the stock control arm locations it will still do ok, just not great for serious rock crawling. It'll be great on normal mountain trails and such.
 
Quite well actually. I know I'll be running a 4 link in the rear. The other issue that I neglected to mention is that I'm worried that a 3 link may not be strong enough.
 
A properly built 3 link is more than strong enough.
 
VAhasnoWAVES said:
the problem with building your own is typically a lack of space.
Click to expand...

with a parallel 4 link? theres plenty of space. but it does "bind" but every setup typically run in the front of an XJ does save for a 3 link.

the space issue comes up when trying to run/design a triangulated link setup.

ShortBusProdo said:
Well here comes there kicker. There will be unimog 404 portal axles in the near future.
Click to expand...

good luck fitting those without running an obscene amount of lift.
 
93XJLI said:
with a parallel 4 link? theres plenty of space. but it does "bind" but every setup typically run in the front of an XJ does save for a 3 link.

the space issue comes up when trying to run/design a triangulated link setup.



good luck fitting those without running an obscene amount of lift.
Click to expand...

The lifting won't be an issue, I only need 4'' tops to achieve my desired wheel height. Considering the portals give me a 6'' drop without lift. The main issue is the weight of the axles themselves and I'm worried a 3 link my not pack the desired punch.
 
ShortBusProdo said:
The lifting won't be an issue, I only need 4'' tops to achieve my desired wheel height. Considering the portals give me a 6'' drop without lift. The main issue is the weight of the axles themselves and I'm worried a 3 link my not pack the desired punch.
Click to expand...

lift is an issue. you need to clear the oil pan and that pumpkin is huge and you're moving it up 5". my buddy sam (ktmracer419) had oil pan clearance issue with a very small truss on a D44 running 2" on lifting when fully tucked, you're looking at at least 6" of lift, PLUS the 5-6" of lift the portals give you, so a total of almost a FOOT of lift.

the 404s weigh no more than a 1 ton D60, so weight isnt an issue.
 
93XJLI said:
lift is an issue. you need to clear the oil pan and that pumpkin is huge and you're moving it up 5".
Click to expand...
No, you aren't moving the pumpkin up 5". The axle is going to be mounted in same location as a regular non-unimog axle, you are just moving the axis the tires are rotating about 6" downward.
 
I understand there may be slight clearance issues with the pumpkin, but I've seen ways that people have made it work, just not with an XJ. I realize the pan is a lot lower than say a TJ or YJ. I feel 4'' should suffice, unless anyone has further input.
 
All cons have pretty much been stated so far except the bolt on kits that still utilize the stock uca 10mm bolts. Combine all the forces at work from bigger tires and low gearing and such with the bind of a 4 link in flexy situations, those bolts are easily sheered off. Especially on a radius arm setup, definitely go true 3 or 4 link. Now I dont know too much about portal axles but Im guessing what 93xjli was hinting on is that you have to take into account the lift the axles will give you, because THEY WILL add lift. If you want a final lift of 4", so you buy 4" or more likely 4.5" coils and throw then on a dana 30. Your final lift will be about 4". Then you'll throw portals under there and like you said, it will actually drop your tire center down about 6". So your current 4" lift coils will stay the same compressed length where they are sitting on top of the portals (just like that sat on top of the 30) but instead the distance from the bottom of the coil bucket to your tire center will be increased 6". There for, 12" of lift.
 
redrider2911 said:
All cons have pretty much been stated so far except the bolt on kits that still utilize the stock uca 10mm bolts. Combine all the forces at work from bigger tires and low gearing and such with the bind of a 4 link in flexy situations, those bolts are easily sheered off. Especially on a radius arm setup, definitely go true 3 or 4 link. Now I dont know too much about portal axles but Im guessing what 93xjli was hinting on is that you have to take into account the lift the axles will give you, because THEY WILL add lift. If you want a final lift of 4", so you buy 4" or more likely 4.5" coils and throw then on a dana 30. Your final lift will be about 4". Then you'll throw portals under there and like you said, it will actually drop your tire center down about 6". So your current 4" lift coils will stay the same compressed length where they are sitting on top of the portals (just like that sat on top of the 30) but instead the distance from the bottom of the coil bucket to your tire center will be increased 6". There for, 12" of lift.
Click to expand...

Thank You that helps. I understand the portal boxes give lift and to add it to my existing suspension lift for the overall. Do you think that a true 4 link would bind at all?
 
ANY 4 link does bind at some point, its why you need atleast 2 poly or rubber joints on the axle end of the setup just like yossarian said. They have to be able to squish, if I was going to run my 4 link I would run all poly bushings at the axle end. This is because all the needed squish would be spread across 4 joints vs 2 joints, the joints would last longer. A 3 link can be run with all solid joints, heims or johnny joints ect. This is because it doesnt have a 4th upper link fighting with the opposite upper link as well as the trackbar. The trackbar is a big cause of the binding in the big picture. Thats why when you go to a triangulated 4 link without a trackbar, you can run all solid joints. Now before you go off on that, remember you wouldnt want a triangulated 4 link up front. Your axle would move strait up and down through travel and not with a pivot point to the side like your drag link and track bar do. You would get a crazy amount of bumpsteer and probably wouldnt be able to turn at all at full flex. Therefor you would have to go full hydro steering. Not to mention find out how to a tri 4 link under the front of a XJ.
 
im running my own 4-link + tracbar. OEM bushings axle side, Johnny Joints frame side. i wouldnt run anything different. SUPER stable when climbing near vertical obstacles but my wheelbase helps with that too.
 
A properly built 4 link will not bind until you run out of suspension movement for other reasons like shock length etc. The longer the arms the more they flex before binding.
 
A triangulated front 4 link can fit. I love the way mine works, but I'm not sure it's worth the effort. There are plenty of 3 link w/ panhard designs to use for ideas.

-Jon
 
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