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I think MommyMallCrawler used a 2.5 RK lift kit and flat fenders and ran 37s without issues. Try it without the body lift. I've had 35s on a 1.5 RK lift for years with chopped fender flares
 

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We also ran 37" tires with a 2.5" lift and flat fenders. No issues.
I would try it and see before adding the body lift, unless you just like the look of a body lift.
 

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One way to correct the caster problem with JK axles.
4462784
 

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I started asking questions about Rancho Geo brackets in another thread, but then I discovered this one. So yesterday I finally added them and just couldn't believe the difference. Night and day. My 2-dr JK has a 2-inch lift and it is getting up there in miles. It is on (and will stay on) 285/70r17s and I need it to last.

My main complaint was feeling every bump in my teeth and wandering at highway speeds. So far the Ranchos have my jeep driving like a sedan. From 1 mph to 80 mph there is zero vibration.

Pre Rancho -
Front LT Caster: 3.1
Front RT Caster: 3.0

Post Rancho -
Front LT Caster: 5.0
Front RT Caster: 4.9

Next question I have is, am I done? Is there any value to be gained by replacing my 2-in lift with a 2.5-lift to possibly improve the Pinion?

Thanks!
 

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Front pinion angle and caster work together. You change one the other changes. You can change one the Geo bracket bolt hole to change the pinion angle but with only a 2” lift you may already be at the lowest setting. If you have no shakes or vibes I’d leave it as is


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2013 Jeep Wrangler Rubicon 10th Anniversary Edition
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wow, a lot of posts! I just did Metalcloak 2.5" lift and thought I needed 6* caster but reading here it sounds like I should have the shop set it at 5.5" instead? is that right?

35" tires, 2.5" Metalcloak True Dual Rate lift with adjustable upper control arms.

gains right about 2 inches of lift on my 2913 JK Rubi 10A.

help?
 

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wow, a lot of posts! I just did Metalcloak 2.5" lift and thought I needed 6* caster but reading here it sounds like I should have the shop set it at 5.5" instead? is that right?

35" tires, 2.5" Metalcloak True Dual Rate lift with adjustable upper control arms.

gains right about 2 inches of lift on my 2913 JK Rubi 10A.

help?
Typically you want around 5 degrees of caster, give or take a half a degree. But it also depends on things like tire size and how you like your Jeep to drive. More caster is more stability, but there is always a price. More caster can make the steering slower.
Also, you often have to compromise between caster and pinion angle. Sometimes you would want more caster but it may cause pinion angle issues. So you compromise.
 

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Could you get vibrations in the front driving in 2wd with too much caster and too little pinion angle? Saw 5* caster vs 4.5*?

I'm thinking my telling them 6* was too much but trying to decide if I should have them set it closer to 4.5* to see if that eliminates the minimal vibration I felt at 40mph -- though that may have been caused by other issues (track bar length off, steering out of wack, toe etc etc...

Maybe have them set to 5* and complete alignment and then see what happens?
 

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Could you get vibrations in the front driving in 2wd with too much caster and too little pinion angle? Saw 5* caster vs 4.5*?

I'm thinking my telling them 6* was too much but trying to decide if I should have them set it closer to 4.5* to see if that eliminates the minimal vibration I felt at 40mph -- though that may have been caused by other issues (track bar length off, steering out of wack, toe etc etc...

Maybe have them set to 5* and complete alignment and then see what happens?
If your pinion angle for the front axle is off, it can cause vibrations whether you are in 2WD or 4WD. The drive shaft is always spinning, so the potential for driveline vibrations is always there.
If you have the MetalCloak with adjustable upper front arms I would just keep adding a half a turn at a time until the vibration is gone. You might want to go with a full turn the first adjustment, but after that you could do it in half turns. You should be able to do that in your driveway.
A simple test to see if it is the front drive shaft causing the vibration is to remove the front shaft and drive it. It is a pass / fail test, if the vibration is still there the vibration is not caused by the front pinion angle. But if it is gone, it is.
 

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Thanks -- I can do that, though these have only one adjustable end so I'd have to remove that end, rotate, put back on and then do the other one etc. I can do that.

Should I just have them set the caster at 4.5* or 5* with the alignment instead of the 6* I was originally thinking? Just looking for the best start point.
 

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Thanks -- I can do that, though these have only one adjustable end so I'd have to remove that end, rotate, put back on and then do the other one etc. I can do that.

Should I just have them set the caster at 4.5* or 5* with the alignment instead of the 6* I was originally thinking? Just looking for the best start point.
If no driveline vibrations then leave it. Assuming you have the stock driveshaft? Its a little more lenient with pinion angle.
 

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Stock driveshaft, a little vibrations with the caster at 5* from my measurements. Hence my contemplating what I should have them set it at. We did discuss setting it at 6* then driving and seeing how it did but I'm thinking it may be better to set at 4.5* (stock I think) and then driving it to see what happens.
 
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