Adjustable front upper with new lower control arms?

[KwoodKing]

Howdy,
I installed the Rock Krawler Adventure Series 2.5 TT kit last week. I’m experiencing some poor steering over bumps and slow return to center when turning. I know it’s not the track bar and drag link geometry being off, as we got an adjustable track bar and lengthened the drag link to center the steering wheel. (The steering wheel dosent turn when I jump on the front bumper)
The kit came with new slightly longer front lower control arms so that makes sense how the caster is off. My problem is the caster being 7 degrees when Mopar and Rock Krawler suggest between about 4 and 6. Should I just get adjustable uppers or both adjustable uppers and lowers to push the axle forward and straighten it up?
JL 2.5 Adventure System Mid Arm

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[word302]

Howdy,
I installed the Rock Krawler Adventure Series 2.5 TT kit last week. I’m experiencing some poor steering over bumps and slow return to center when turning. I know it’s not the track bar and drag link geometry being off, as we got an adjustable track bar and lengthened the drag link to center the steering wheel. (The steering wheel dosent turn when I jump on the front bumper)
The kit came with new slightly longer front lower control arms so that makes sense how the caster is off. My problem is the caster being 7 degrees when Mopar and Rock Krawler suggest between about 4 and 6. Should I just get adjustable uppers or both adjustable uppers and lowers to push the axle forward and straighten it up?
JL 2.5 Adventure System Mid Arm

I’d start with adjustable upper. 7° isn’t horrible, you want to be around 6.5. Where is your toe set at? What tires/pressure are you running?

 

[KwoodKing]

I’d start with adjustable upper. 7° isn’t horrible, you want to be around 6.5. Where is your toe set at? What tires/pressure are you running?

PSI is 32 all around on the 31.5” Michelin ATS street tires.

here you can see the knuckle rolled back.

here you can see the drag link and track bar running near perfectly parallel (as good as it was stock)

here is the alignment stats from the dealership.

 

[word302]

PSI is 32 all around on the 31.5” Michelin ATS street tires.

here you can see the knuckle rolled back.

here you can see the drag link and track bar running near perfectly parallel (as good as it was stock)

here is the alignment stats from the dealership.

The first thing I’d do is try a little bit more toe in. Your caster is definitely on the high end, but not so much so that I’d expect a huge change. If playing with the toe doesn’t help then I’d definitely add adjustable uppers. 2.5” lift and 31.5” tires?

 

[KwoodKing]

The first thing I’d do is try a little bit more toe in. Your caster is definitely on the high end, but not so much so that I’d expect a huge change. If playing with the toe doesn’t help then I’d definitely add adjustable uppers. 2.5” lift and 31.5” tires?

Yes, you’re correct on the lift and tires. I’ll play around with the toe, nothing too scientific, and see what comes about. It does seem wonky that Rock Krawler and even Mopar sell incomplete kits. Sure wish I thought about this but I guess now I can pick and choose which parts fit the jeep - it stands for “Just Enough Essential Parts” for a reason!

 

[word302]

Yes, you’re correct on the lift and tires. I’ll play around with the toe, nothing too scientific, and see what comes about. It does seem wonky that Rock Krawler and even Mopar sell incomplete kits. Sure wish I thought about this but I guess now I can pick and choose which parts fit the jeep - it stands for “Just Enough Essential Parts” for a reason!

You have to realize you bought a kit with non-adjustable control arms. They’re going to give everyone a slightly different caster measurement. If you go to another alignment shop you’ll likely have a much different caster measurement. I wouldn’t call the lift you bought incomplete. It’s one of their lower end kits for a reason. If you want precise caster you have to buy adjustable components.

 

[KwoodKing]

You have to realize you bought a kit with non-adjustable control arms. They’re going to give everyone a slightly different caster measurement. If you go to another alignment shop you’ll likely have a much different caster measurement. I wouldn’t call the lift you bought incomplete. It’s one of their lower end kits for a reason. If you want precise caster you have to buy adjustable components.

I agree with you on the point about everybody reading a different caster, however, it dosent seem wrong necessarily to have fixed uppers or lowers, so long as the fixed one supplies a solid base for an adjustable other to dial in the rotation of the axel. Correct me if I’m wrong, I asked the question because I know enough to I don’t know enough. Thanks for helping figure this out with me, I appreciate it.

 

[word302]

Yeah those lowers are going to be a good length for you to add uppers and get things centered in the wheel well. The reality is the only way to dial things in perfectly is with adjustable uppers and lowers.​

 

[jaymz]

It’s not a rule set in stone, but adjustable lowers are typically best for adjusting wheelbase, and uppers for adjusting caster.

 

[marie]

Is it a 2 door and did you check your rear pinion angle?

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