Did I screw up by installing Johnny Joints with radius arm setup?

Brent T

New member
Here's the scoop. I installed a TNT radius arm setup about a year ago. Did not replace the 15 year old stock UCA bushings at that time. Noticed a couple months ago they were shot so I thought I'd upgrade to Johnny Joints instead. Seemed like a no brainer. I have not wheeled it yet, but ran across some info where it sounds like this is not a good setup to run with radius arms due to the JJ's not having any "give" when the suspension binds.

The TNT setup is a hard joint at the frame end with rubber bushings at the axle end upper and lower. Now I have hard joints at the frame end, rubber at the LCA and JJ's at the UCA's.

It drives great on the street. Am I gonna break stuff if I don't change the UCA's back to rubber or poly bushings?


NAXJA Member
NAXJA Member
You'll be fine, the lowers still have plenty of give. I modified my re radius arms to run heim joints at the upper axle mounts when I swapped in the hp44 2 years ago with no problems.


New member
You'll be fine.

You may wear out the LCA rubber bushings faster, but I wouldn't worry about breaking anything.

The more rubber bushings you have, the more points you have to absorb the binding. Focus it all on one bushing on an arm, and you're just accelerating the wear on it.



NAXJA Member
NAXJA Member
I had great success for a few years with the following setup:

Driver UCA, axle end: Johnny joint, 1/2" bolt
Driver UCA, LCA end: Rubicon Express small flex joint, 1/2" bolt
Both LCAs, axle end: rubber bushing
Both LCAs, frame end: Rubicon Express large flex joint
Passenger UCA: removed

Olympus Off Road

New member
I'd run it. If you are still running the stock passenger uca tower I would just keep an eye on that. That would be the next source of deflection and they are pretty known to bend and eventually crack off with radius arm setups as is. If you have the Currie weld-on tower disregard this message.