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Radius arms in the rear?

chad

NAXJA Forum User
Location
lancaster, CA
Ok, I searched, but I did not find. It seems that since nobody's using a radius arm type suspension in the rear that it shouldn't be done. So I'm just wondering, why?
I know it's probably a dumb question, but I couldn't figure it out on my own, so I thought I'd ask.
Chad
 
It has been done, but you have to run a panhard or trackbar for side to side control. The beauty of a double trangulated 4-link is that you dont need one.
 
if you ran 2 radius arms in the rear, it will bind and not flex real great. If you ran one wristed, or one with a single upper, then you get the axle's rotational forces only applied to one side of the vehicle, resulting in odd handling.

also, in most instances the anti-squat percentage is much too high
 
Pajero's or Montero's to you I think. They ran them in the rear and what is I based my setup on but used Range Rover trailing arms to do it. Worked really well. They are different from the Ford type though as they connect in front and behind the axle the same as Patrol and Landcruiser 80 series on do at the front.
 
mad maXJ said:
if you ran 2 radius arms in the rear, it will bind and not flex real great.

Why? On my rig flex is only limited by my front shocks. My arms are lengthened, but not wristed & I'm using 14" travel shocks. I can't see why the rear would bind & not flex. The geometry of using single arms for the rear suspension is something I'll leave to those that have been there.

Matt
 
i'm sure you understand the natural bind in a radius arm suspension, imagine if the links were welded straight to the tubes, it wouldn't be able to flex at all. All your flex is coming by deflection in the bushings, and the more deflection the bushing allows for, the more slop in the system. This may not be a big deal in a front application, but one of the greatest things about linking the rear is eliminating axle-wrap, which you wouldn't be able to do with soft bushings on a radius arm rear.

now that said, I have, and I guess I still am, seriously considering trying them in the rear of my MJ. I would make the arms probably over 40" long and run fairly stiff bushings, this would probably allow for decent flex, but I know it would be less compared to a good 4-link.
 
I fully understand the dynamics of a radius arm suspension. The bind you talk about is present & acts like a sway bar generating force from one side tire to the other. To me this is the best of both worlds. Stability yet full range of motion. The axle hop you talk of would be no different than a linked suspension using poly or rubber ends. I highly doubt that you would ever feel it. I didn't mean to get into a huge debate over this, but I couldn't let your statement stand. You do not have to wrist one radius arm to have this setup flex just fine. In fact I've seen some pretty negative characteristics from wristed "C" bushing ford arms that would lead me to never recomend doing this. A good four link or a lengthened radius arm will still only be limited by your shock length. Most 4 link guys seem to be migrating over to installing antirock sway bars. The radius arms have them already built in. THe only difference is that the ford style arms can't be adjusted for roll stiffness except for installing stiffer poly bushings.

Matt
 
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