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Ok I brought my jeep to a specialist for alingmnets and a local jeep guy. My caster angle is 2.5 and I know stock it should be 4. First question is what does this effect for drivability. Does this cause flighty steering?

Second I'm debating now getting a adjustible arm kit as I plan to go to 3.5" lift shortly. Currie has a complete upper and lower set for 898 with free shipping. Now the concern is if I bring it to let's say 5 with my current 2.5" lift will this change the pinion angle enough to cause some problems with the driveshaft? I'm still learning but everything I've been told and read says I could be looking at more problems by adjusting back the caster and going higher. :skull:

OH almost forgot, My 35" tires are on the way!!! WAHOOOOOOO:usa:
 

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Ok I brought my jeep to a specialist for alingmnets and a local jeep guy. My caster angle is 2.5 and I know stock it should be 4. First question is what does this effect for drivability. Does this cause flighty steering?

Second I'm debating now getting a adjustible arm kit as I plan to go to 3.5" lift shortly. Currie has a complete upper and lower set for 898 with free shipping. Now the concern is if I bring it to let's say 5 with my current 2.5" lift will this change the pinion angle enough to cause some problems with the driveshaft? I'm still learning but everything I've been told and read says I could be looking at more problems by adjusting back the caster and going higher. :skull:

OH almost forgot, My 35" tires are on the way!!! WAHOOOOOOO:usa:
Yes, less caster will cause some flightiness. Hopefully PhilD or JimP will chime in for you. They seem to be the best at explaining this. There is already some good info on this if you search for it. I'll see if I can dig something up for you. If you're only running a 2-1/2" lift, you could probable get away with running 5 degrees of caster, but I would set it at about 4.5.
 

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How do you like the way it drives? If the steering feels fine to you then I wouldn't be overly concerned right now, but it is something you will need to address as you lift the vehicle more. Right now, adjustable control arms would allow you to dial in more caster without too much of an issue.

When you lift the vehicle more the caster/pinion angles will worsen and a lot depends on what driveshafts you use, if you use a double cardan type aftermarket shafts, pinion angle will take precedence over caster, so caster will be dictated by pinion angle. If you use factory driveshafts then you can pretty much set the caster to what you want, although you may run into some front driveshaft issues at some point and end up with an aftermarket one anyway.

Factory spec for caster is 4.2° ±0.5° (ie: 3.7° - 4.7°). I have found that 2.5° or so is as low as you want to go and still be comfortable. Anything much less and the steering starts feeling too squirrelly and light.

The higher you go on caster, the higher the pinion angle becomes. With a double cardan front shaft you will get vibration from too high a pinion angle leading to issues, so you have to compromise caster a little to maintain a usable pinion angle with no or minimum vibration.

With factory shafts pinion angle is not so critical, but the slip boot may catch on the auto tranny pan and get ripped, and the boot at the CV at the t-case end can become worn and split from the angle. Running at the low end of factory spec is going to be better for the driveshaft than running at the high end.

The more you lift the vehicle, the worse the relationship between pinion and caster becomes. Also as you lift the vehicle the axles move closer together, thus making the angles even worse. Adjustable control arms not only allow you to set the correct angles, they also allow you to move the axles where they should be.

I run 2.5° of caster and it is okay, not perfect but safe enough in terms of the steering which is not overly light. A little more caster would be nice, but in my case I start to get too much driveline vibration, so I live with it.
 
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