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A 4 link I hadn't seen before

FloydXJ

NAXJA Forum User
NAXJA Member
Location
Salt Lake City
So here is a 4 link set up I had not seen before. My main objective is to see if anyone is running this kind of thing out there, and see what kind of undesireable side effects it mya cause aside from those listed. I was talking to a local guy recently that does a lot of work on XJ's. I was saying I wanted to modify my set up from radius arms as it is now to something with less binding. Most likely a 3 link. He showed me what he had done to his friend's jeep and I thought wtf? Both the upper control arms were moved back up to the frame, but not to stock position. It is pretty much like taking your radius arms and moving them direclty up to the bottom of the frame rail. The arms are about the same length as the radius's were, just attached to the frame instead of the lower arms. He said his intention was to get the uppers on the frame and as horizontal as possible - both at no angle. Plus, they end up triangulating a little bit. So, what do you think of this? My first thought was that the pinion angle during axle movement will always be forced downward, but he said it has not been an issue as far as maxing out joints or anything. When it comes down to it, this set up is easier on UCA axle bushings than radius arms, because when flexing, since both arms are level, they will both be pulling backwards similarly whether going up or down. So the difference between where each upper wants the pinion angle to be will be much smaller than that of radius arms. For my jeep, I will wait and do a true 3 link with a long upper, but I was still kind of interested. The guy whose jeep this was on was an admitted pavement pounder. Despite the 9" of lift and 35s, he said it rarely went off the road and has open diffs. Is this news to anyone else, or is this set up already known and I have been on Mars?:rof:
 
i think i've read some posts that have mentioned this set up a few times. They have said its not a ideel setup sense it changes the pinion angle as well as the caster or camber(can't remember which changes the front to back angle) angle and effects the steering.
 
Equal or near equal length arms are far more desirable for a number of reasons. If you do a 3 link be sure to make a very sturdy frame side mount for the upper arm and weld the axle tubes to the diff housing.
 
For sure - like I was saying, I am not really interested in doing the mod to mine, I was just checking it out. I am in the air for how exactly I will do the 3-link. The UCA mount on the axle is a TNT D44 truss, so I feel good about that mount. I was going to get under some XJ's at the fall fling and see what kind of frame mounts are working well for other 3 linked XJs. Maybe a reinforced RK 3 link mount?

The guy with the short uppers said it handled really well on the road when the upper arms were horizontal. When mall flexing on barriers and such, it flexes well, too. I still wouldn't run it though:roll:




Equal or near equal length arms are far more desirable for a number of reasons. If you do a 3 link be sure to make a very sturdy frame side mount for the upper arm and weld the axle tubes to the diff housing.
 
Aren't you describing a standard triangulated 4 link that you often see on rear suspensions?

Sort of, although I think the upper links are kept longer than this, and a track bar is still being used, as the triangulation is minimal - aka not enough to hold the axle in place
 
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