Stiff Suspension

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RubiconMan

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Joined
Jun 17, 2017
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Location
Peoria, AZ, United States
I used to have a 2" OME lift on my 2004 Rubicon. I swapped out the OME shocks for Rancho 5000X (Part Numbers RS55239 and RS55241) for TJ's with a
2-3" lift a smoother ride. Prior to adding 35" tires, I added a 2.5" coil spacer for a total lift of 4.5" but I still am running the same Rancho shocks. My question is
do I need to replace the Rancho Shocks with Rancho Shocks that support a 4-5" lift for a smoother ride?
 
Your suspension isn't stiff. Nor are your shocks. Your shocks are now too short and are running out of down travel, which is yanking the axle off the ground.

Get longer shocks.
 
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RubiconMan said:
Do I need to have my control arms adjusted due to the 4.5" lift?
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Yes.

And you need to adjust the track bars

And…

do you want to do these one at a time?
 
RubiconMan said:
At least I have adjustable track bars and control arms. Can most jeep shops do this?
Click to expand...

Most Jeep shops should have no problem putting the right sized shocks on and adjusting your adjustable track bars and control arms.

What you want to watch out for is any shop that wants to correct your problems with what they sell even if everything you have is OK and just some quick easy adjusting would do the trick.

FWIW, I bet they'll try to sell you new springs as soon as they see the 2.5" coil spacers. which might not be the worst part of what they say you need to buy.
 
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RubiconMan said:
Do I need to have my control arms adjusted due to the 4.5" lift?
Click to expand...
Adjusting your control arms is not the real answer for the rear pinion angle. With the stock rear driveshaft the rear pinion angle still needs to be parallel to the tcase output shaft angle and now, due to your 4.5" lift, the driveshaft u-joints are nearing their angular operating limits. For a 4.5" lift you really need to install a SYE kit into the transfer case and replace the factory driveshaft with a DC (double-cardan) driveshaft. 4" is the usual time for that to be done.

This is how the rear pinion angle needs to look with the factory single-cardan driveshaft which is how the factory adjusted it.
2joint_angle.jpg
 
Jerry Bransford said:
Adjusting your control arms is not the real answer for the rear pinion angle. With the stock rear driveshaft the rear pinion angle still needs to be parallel to the tcase output shaft angle and now, due to your 4.5" lift, the driveshaft u-joints are nearing their angular operating limits. For a 4.5" lift you really need to install a SYE kit into the transfer case and replace the factory driveshaft with a DC (double-cardan) driveshaft. 4" is the usual time for that to be done.

This is how the rear pinion angle needs to look with the factory single-cardan driveshaft which is how the factory adjusted it.
View attachment 311357
Click to expand...
Hi Jerry,

Thanks for you reply, I have a 2004 TJ Rubicon with a Tom Woods Driveshaft and double cardan ujoint.

John
 
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JEEPCJTJ said:
Most Jeep shops should have no problem putting the right sized shocks on and adjusting your adjustable track bars and control arms.

What you want to watch out for is any shop that wants to correct your problems with what they sell even if everything you have is OK and just some quick easy adjusting would do the trick.

FWIW, I bet they'll try to sell you new springs as soon as they see the 2.5" coil spacers. which might not be the worst part of what they say you need to buy.
Click to expand...
Should I get rid of the coil spacers and just purchase coil springs for a 4" lift?
 
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From a ride quality standpoint, I wouldn’t think so, but you could also unseat a spacer under flex that may not seat back properly. 2.5 is a pretty big spacer imo.
 
RubiconMan said:
Should I get rid of the coil spacers and just purchase coil springs for a 4" lift?
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This is still about the best deal for 4 inch springs. I'm running them on my LJ and have no complaints. Sell your current springs and spacers and you will probably make enough money to pick up a body lift so you can clear your 35's properly.

https://www.summitracing.com/parts/ran-rs66113b-3
 
RubiconMan said:
Is there a disadvantage to using coil spacers vs just a coil spring for a 4" lift?
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If and when it matters, relying too much on spacers can reduce up travel due to excessive bump stop requirements and they can reduce the otherwise useable free length of the spring.
 
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