Thanks for posting the charts.
I actually have no clue what engine or transmission Wayoflife was referencing when he addressed the question.
Your chart makes me think that 4:88 is the top of the scale for my application. My only concern now is,does your chart take into account the transfer case gearing in my 2017 JKUR? If so, I agree that I don’t want to go with 5:13s.

The plot thickens,and questions continue.
Thanks so much for the effort you’re putting into my project.

Cheers

 

Y, 99.9% sure what you were reading was for the 3.8L engine.....which you indeed HAD to gear that low to get any guts back. Again, note that those gear charts are off the actual tire measurements. None of these tires will actually measure what is stamp on em when installed and aired to the PSI you'll run. They also vary fairly widely based on brand. Nittos and Toyos are closer to what's stamped on em, but again, air pressure. For example, my 37" Nitto Trail Grapplers with 30k miles inflated to 28psi measure just a tad over 35" right now. You're not gonna run a tire like that pumped up to 40psi.

Your Rubi TC is only coming in to play in 4Lo. in 2wd and 4Hi, you're 1:1 like the rest of us, so it's not going to affect your on road gearing, but that is also what I was pointing out earlier....another reason you don't have to go so low. Someone like me who doesn't have the Rubi TC has to gear a little lower the ideal, sacrificing on road high end fuel economy to get a little more low end offroad benefit. 4.88s would lean on the aggressive side with 35s on the road (pretty much like where I'm at), but would be perfect once you make the jump to 37. You don't want to do that job twice, so if you REALLY think you'll eventually end up on 37s, you need to select gearing that will be acceptable with both sized of tires. If you were NOT going to consider 37s, then you'd be looking more at 4.56.

Do you have 3.73 or 4.10 factory gearing? I will say you can make it for a little while with 35s on the factory gearing. It's not perfect, but doable. You don't have to have it done immediately, so really consider your build and be honest with yourself.

Also, don't forget to budget for steering components. Those bigger tires add a lot of stress. You'll get a new track bar with the suspension parts, but Tie Rod, drag link (probably a high steer) if not included, and ball joints. If you're going 37s, you need to be thinking about Rare Parts ball joints....and their ~$600'ish. You can research that up, but plan on those wearing out. Rear driveshafts will last a while....much less important than the fronts when it comes to replacing....just be sure to skooch your evap skid over a bit or better yet, relocate it....you can search up the Teraflex vid on evap skid, or look at relocation kits.