I had my 2018 Rubicon lifted 3 1/2 inckes (Rough Country) and 35 inch wheels with Toyo Open Country tires. Even after 3 alignments the Jeep was flighty at most speed on 2 lane roads.
I had shocks changed to Fox BDS and a Fox BDS steering stabilizer installed. There was improvement but still too unstable on bumpy roads.

Any suggestions on how to improve?

 

Get rid of the Rough Country suspension and go 2-1/2" MetalCloak Dual Rate or similar quality. Did you change the track bars and install adjustable Control Arms (at least either of the top or bottom arms) to reset the caster? For 35" tires you went way too high unless you are planning even bigger tires. 2.5" and trimmed or aftermarket fenders will allow 37" tires then your wallet starts to groan because you are chasing gearing changes etc. What I would surmise is happening with your present setup is the Jeep is soft and leans with road undulations which requires constant steering inputs - is that a close assumption?

 

Rough country uses poor suspension design to keep its costs down to suck people into buying their lifts. The biggest issue with their geometry is the drop pitman arm and the drop brackets that they use on the track bar. This lowers your roll center and makes the jeep more unstable with increased body roll. I believe their coils are a bit softer which is good for off road crawling but on road can cause some handling issues. At 3.5"+ of lift a high steer kit or drag link flip should be used to flatten the steering links up front and a raised track bar bracket on the axle should be used. This will minimize the wander and bump steer you get from the extreme angles of those links. For 35" tires 3.5" of lift is a bit much and a good 2" kit would be better for you with fewer components needed for a good on road ride. You can throw an incomplete crap lift on a jeep and it will perform decent off road but for on road performance you really need to spend the extra time and money to make sure it is set up right, after all you don't want issues when you are driving 70 mph.

 

Sixty4x4 you hit the nail on the head.
Obviously I would like to minimize future mods, is there any options to keep Fox shocks and achieve some stability?

 

Depends on the length of the shocks, as lowering would help. If you want to maintain the height you have now remove the drop pitman arm and reinstall the factory arm, install the high steer drag link flip with raised axle track bar bracket, remove the rear frame side track bar drop bracket, and raise the rear lower track bar bracket

 

I should start keeping a running list of these RC threads so when someone brings up RC as an option I can just say "here's a list of threads to read through". It's the same problem. Every. Single. Time.

 

Hey Peterbately - Dirtman gave you some good advice. I would think the fox shocks would still work based on the advice provided. Independent shops on your area can usually offer good unbiased advice.

 

before throwing the bath out with the baby water... what are the alignment specs?

 

Thanks for the help. The front high steer kit improved the instability 100 per cent. Still thinking of dropping the bracket in the rear.