I am putting money aside to do a tire + suspension upgrade on my 2015 rubicon when my stick tires get a little closer to their end of life.
I know this is a popular topic but I haven been able to answer all my questions. This is a daily driver, frequently on the highway, however I would really like to get my ground clearance to 12".
Here are my questions.
What do you mean by 12"? The bottom of the pumpkin is just under 9" from the ground on a stock rubi. These are 32" tires. You cant change that with suspension, only tire. Since you need 3.2 inches, the OD of your tire must be 6.4" bigger than your stock set up. 38.5" should do.
If you are talking frame rail to ground, that is already over 12 from factory. 15.4". So please clarify.
1. What size tires can I get to without sacrificing driveline performance. (4:10 gears)
Any tire heavier than what you have will hurt driveline performance. Going bigger, they get heavier. You can get 33s on without doing anything to the suspension. 2.5" lift will get you 35s.
2. I'm currently thinking 33s would be about right. What is the minimum suspension lift i need to avoid unwanted contact while wheeling?
Dont need one at all. Depending on the width of the tire you will either want wheels with less back space or (not recommending) a spacer.
3. What else do I need to do this right? I would like to keep a similar caster angle.
Then get 33s and dont lift it. Or get lower control arms with the front on whatever kit you decide on. There are a bunch of these types of threads since there are 9 years of guys with JKs asking the same questions. Keep searching. The answer to everything is "It depends".