I have a 2011 JK, 4 Door, Automatic, with a TF 2.5 coil lift and 33" Duratracs (measured height of 32"). 90% of my driving is highway. Flow of traffic is 75-78 mph. I seriously doubt I will ever go to 35s. I like the look as is, and for a DD it works for me.

So that being said, I ordered my gears today after saving up for quite some time now. I ordered the 5.13s after much debate. Now I am not so sure I made the right call. I can probably catch Northridge before they ship, so did I make the right call? Are the 5.13s with 33s (32" mounted) going to be WAY overkill? I do not do any towing, we have small rolling hills here, nothing steep, but not sea level either.

I am currently getting an average MPG of 14.03 MPG with 33s and 3.73 gears. The highest MPG I have ever gotten post mods is 15.97. If I could get 16 MPG all the time I would be happy. I plan to get an AEV Procal when I install the gears (Superchips not available for the 2011s, and they don't forsee it being ready any time in the next 6-8 months).

 

Yeah, 488 sounds more like it.

 

Based on your description you want to change the order to 4.88's. I'm 5.13's on 35's and they're perfect except when I'm climbing mountains on highways with my jumping jack trailer.

 

Too much! Get the 4.88's

 

On the chart it is only about 150 RPM difference. Does it really hurt to go 5.13?

 

I agree I would do 4:88's unless your planning on 35's eventually.

 

I have the same setup on a 2-door with stock 32" tires that measure just under 32". On the highway at 60 MPH the engine turns about 16-1700 and returns a solid 22-23 MPG. I don't have any 75 MPH traffic to run with where I live.

The factory setup with 3.73 and tires just short of 32" seems about perfect for a DD. I'd be looking for gears that increase the final drive ratio by the same percentage as the increase in tire circumference. In other words, if the distance around your Duratracs is 10% greater than the stock tires, then you want gears that are 10% lower. 3.73 X 110% happens to be almost exactly 4.10. It is only about 4% further around a 33 than a 32, so even 4.10s will gear you lower than a stock 32" tire on 3.73s.

If you want the Jeep to be geared a whole lot lower for some reason, go for the 5.13 or 4.88 or whatever. If you want a DD, I'd try to find some 4.10s. 5.13s will increase your engine speed about 37%, so what was 2000 RPM would become about 2740.

Anybody wanna check my math?

 

x2 if you think you will go to 35's, if not go with the 4:88's.

 

Seems like from the chart in the FAQ that 5.13s and 33s would put my rpms about the same as a stock 6 speed Rubi with stock tires. That is why I ordered them, as I know the stock 6 speed Rubi performs well. I was expecting mixed answers, seems I was wrong...

 

Keep the gearing and get 35s