Have an 08 JKU that's a DD with a pro comp 2.5 lift with 295/75/16 BFG KO's. Ever since I added the lift he ride had been a lot stiffer than stock. If I change out my shocks would that make my ride smoother or would I need to replace the springs as well? I know it's a jeep and it will never ride like a luxury SUV but here recently it's riding like a log wagon.

 

What PSI are you running in your tires?

 

Yes

Maybe.

I had this same lift on an old LJ of mine and I actually liked how it stiffened things up but I also had Metalcloak fenders front and rear, bumpers, sliders rear corners etc.. so was fairly heavy.

If you have not had the lift on very long give it a couple weeks and see how you feel, you will probably not even notice after spending some time with it.

 

Shocks make a huge improvement in ride quality. What shocks are you running right now? Are they the stock shocks with extensions? Are they the Pro Comp Shocks? A quality shock will help smooth out your ride.

Also as OH9JK asked what is your tire pressure? What size are our tires now?

A lot of people will upgrade the tires and still run the factory pressure. This alone will make our ride more harsh. You will want to perform the chalk test to find what tire pressure is right for you. Not only will you improve your ride quality but you will also improve your tire wear by running the correct pressure.

If you want to discuss anything in more detail feel free to PM us or E-mail us. We are always willing to talk Jeep and help our fellow Jeepers.

 

16" so I'm assuming the tires are D or E rated?
Chalk test them for optimal psi. Shocks are your best bet

I'm running E rated handkooks with Rancho 7000 shocks, but Check out the adjustable 9000's. Soft like a pillow or very firm.

 

Have you verified the caster angle and alignment is correct after the lift? If front axle caster is off by 2 or 3 degrees it makes a big difference in the handling and ride over bumps in roads and things like expansion joints in bridges. Also makes the front end dive when you hit the brakes.

You can check the caster quickly by putting a magnetic dial indicator on the front diff. Just place it vertically over one of the two round flat holes located on the axle housing just either side of the front diff cover. If your alignment is close to factory spec ( 4.2 degrees +/- 0.5) then this round flat spot will be straight up and down on the dial indicator. Just be sure the jeep is parked on level ground when you do this, otherwise measure the slope of the ground and correct what you read on the dial indicator by that same amount.

magnetic dial indicators are $5 at harbor freight or $9 at Lowe's tool dept.

 

Hmm ^ I always thought the circles were Perpendicular to pinion angle. Stock pinion is around 2* so the circles would read 2* or 88* ?

Right now I'm reading 1.5*. That would be mine caster is 3*-3.3*?

 

I not thinking about the pinion WRT caster as much as the ball joint orientation. Mostly I'm thinking about the geometry of the upper ball joints in relation to the lower ball joints. Basically you want the upper ball joint about 4.2 ( perhaps closer to 5 degrees if you have 37s) behind the lower ball joints.
When you lift the jeep the front axle housing rotates forward and the upper ball joint moves forward, closer to being directly over the lower joint. You can remedy this two ways.1) Install longer lower control arms to push the lower ball joint forward or 2) install shorter upper control arms to move the upper ball joints back toward the firewall.
When those circular spots on the axle housing are straight up and down ( vertical, 90 degrees on the dial indicator) the ball joints (and caster) are in good alignment.
If you run big tires the handling can be improved by adding slightly more caster, I.e. putting the upper ball joint even farther behind the lower joint, but this will increase the pinion operating angle to the driveshaft so be careful if you try this. It's a balancing act of what works best for your rig.

 

Aware of all that but good info for somebody learning.
For quick reference those flat circles --from what I read-- are a good spot to gauge pinion angle. With 6* separation you get Caster

I see it explained 2 ways. I want to pass on the correct info and that's why I asked.

 

Fwiw. The two flat circles are perpendicular to the output shaft.
0* measured here would mean caster is at 6*

Stock is 1.8 +/- and I measure 1.5* (caster 4.5*)