I made the charts. The OP stated he has an auto with 3.73 gears. The chart shows what rpm his jeep will run at with those stock gears and and 33s.
The chart just shows what the rpm will be in 3rd and OD given the different gearing. It has nothing to do with what is recommended.

 

Humm thinking if I made charts Id hope that I have them accurate enough charts that were proven. Is your calculated by math or real time?
Is it specific by your tire diameter
Is that an actual 35 or what does it measure mounted on your jeep
Is you speed calibrated?
Canadian KM's or is KM calculated to mph

 

It's calculated with the formula shown on the image. I believe it to be the exact formula that the proven charts where created with.

The formula is:

Gear ratios for an auto is: 1st = 2.84, 2nd = 1.57, 3rd = 1, 4th = 0.69

rpm = (mph * R&PRatio * 336)/tire diameter * gear Ratio

So the RPM on 3.73s with a 33" tire driving 65mph in 3rd = (65 * 3.73 * 336)/33*1 = 2469

Exactly what the so called proven charts show.

 

Well given actual wind drag, weight of gear and inclines and declines of terrain what most people experienced and not calculated is 5.13 is great ratio to go with for 3.8 Auto
If this guy is not running terrain, flat land and mostly freeway riding I'd probably go with a 4.88 ratio with 35's

 

See my other post for the formula.

I notice you have an automatic rubicon with 38 inch tires and 5.38s.
Going 70 mph with 32" tires and stock 4.1 gears your rpm in OD should be about 2079
Put on a set of 38s without a gear change and your rpm will drop to 1751 to do the same speed.
then go and put in 5.38s and your RPM should be about 2298 in OD.

Here is a diagram showing you all the different rpms you would have had depending on what ring and pinion you go with:

 

True, the chart I uploaded only shows you rpm for 3rd and OD. If I was to recommend for 33s(and and auto) I would say 4.56 for better gas mileage but probably should go 4.88s. For 35s I would say 4.88 and 5.13s. Some say 5.13s are too small for a dana 30.

 

Actually that's off from my setup about 200 rpm!!!
But hey it's all calculated so it MUST be correct than real experience.
Just like mine with 4.10 and 35's MTRs
And mine with 4.10's and 35 toyos
And mine with 4.10's and 35 bfg's
And mine with 4.10's and 37 nittos
And mine with 4.88 and 37 nittos
And mine with 5.38 and 37 nittos
And mine with 5.38 and 38 geolanders
I'm not sure calculated but the inefficient Auto revs diff than a calculated stock setup

 

Learn by others lost of money

 

Oh for fuck sakes, take that formula I gave you and run it through any gear size and tire size and then compare the rpm with your proven charts and you will find its exact. That's all I claimed

I doubt your tires are exactly 38" and your speedo may not be accurate either.

 

Ok I never stated 38 or whatever your calculations were. Hostility man wow, just wheres the jeep fun loving attitude at?
I am stating that formulas do not take in consideration of the heat absorption the motor produces and HP loss.
That little motor it has and struggles.
When anyone goes above a 33 inch tire the mileage factor goes out the window
Yes I have seen mileage with 35's lightweight MTRs and even 4.10 ratio
And also 4.88's
That automatic transmission either way be worked by low rpm's or revving high
I can see if this jeep had more HP and torque I'd try to run it at lower RPM to get mileage.