13.1mpg best I can get with 35’s. Questions inside…..

[VBDiesel]

I've got the same wheels but 20s, 3 inch lift, 35 Toyo AT3s, winch and bumper. I get 21.3ish with Diesel. That was quite a drop from stock.

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[AP Double]

No, no crowning and these are my second set of 37 12.5 17 tires I've had on them. I was running Goodyear Kevlar MTRs before. Got about 4,000 miles on the Kanati's and they are wearing evenly so far and look like they are brand new still. I run 33lbs of pressure in them which seems to be the sweat spot and was the same pressure I ran in the Goodyear MTRs as well. I'm pretty sure the stock steel wheels weigh right at 26lbs a piece.

Thank you! This is great; I’m going to keep those wheels then! Really appreciate it. I’ll chime in and report back on my MPG. I’m planning on changing from the 33” Wildpeak AT to the 35” Wildpeak AT. It might be interesting to see what that does to MPG - without changing anything else. Thanks again!

 

[Mac]

This is super helpful. Do you know what those stock wheels weigh? I’m pretty sure that these are the wheels coming on my JT (on order). I was thinking about putting 35’s on them but also wondering if it’s okay to put a 12.5” wide tire on these stock wheels, which I think are 7.5” wide. Have you had any issues with that? Any crowning at full highway air pressure?

Best to check the specific tire manufacturer’s site for wheel size range for tire size you are interested in.

 

[Wilkerbeast]

Try dropping down a gear on the highway. Just an idea. I put 34s on my sport Manual Trans and in sixth gear I get worse mpg because it runs below the power band. At 70 mph I get 17ish mpg. Might work the same on the auto.

 

[InvertedLogic]

I have a similar setup, and just averaged about 18mpg driving from Moab, UT to Denver, UT with speed between 70-85mph.

A couple of things though which might contribute to the difference:

1. I have my tire size calibrated via Tazer
2. I was mindful to pick one of the lightest 35" ATs I could find (Toyo ATIII, 35x11.50x17)
3. I kept my factory alloy wheels (22lb/wheel)
4. Aluminum bed rack (something like 50lb total)
5. RTT looks big, but its pretty low profile when closed, and only weighs about 85lbs.
   

 

[ShadowsPapa]

I have a similar setup, and just averaged about 18mpg driving from Moab, UT to Denver, UT with speed between 70-85mph.

A couple of things though which might contribute to the difference:

1. I have my tire size calibrated via Tazer
2. I was mindful to pick one of the lightest 35" ATs I could find (Toyo ATIII, 35x11.50x17)
3. I kept my factory alloy wheels (22lb/wheel)
4. Aluminum bed rack (something like 50lb total)
5. RTT looks big, but its pretty low profile when closed, and only weighs about 85lbs.
   

So 4 and 5 together weigh less than a typical American adult male........ not bad at all!

 

[Deleted member 28696]

It’s been just over 4k miles so far and mpg just seems to keep dropping. I even baby the S out this thing when driving it. I have a rack and roof top tent so I figured that’s killing it the most. I took it off about a week ago and still getting 13.1 with city/hwy mix. Everyone on this board is posting like 15-20 and many have more mods and bigger tires. So trying to figure out wtf I can do to get more range out of this thing.

I’m wondering if maybe the tazer could be causing an issue somehow. Going to take that off and test this week.

21 rubicon
35” Baja atz with 17” fuel zephyr wheels (kinda heavy wheels).
RR arcus stubby bumper
Taser mini- updated about 2 months ago to fix issues it had.
4h auto ( I wonder if this also drops mpg
I run regular fuel, so 87/89 normally.

Thoughts on stuff to try? I read the thread with the pulsar but that won’t work on the 21 I guess.

After changing to 37x20 Nitto Trail grappler M/T tires my MPG dropped to around 13 MPG due to the weight of the tires and wheels. What fixed it was regearing from 4.10s to 5.13's revolution gears. Now I get around 15-16.5 depending on what type of driving I do. The Gearing also restored the power so it's not sluggish and shifts correctly. Also make sure that you've measured your tires from the top of the tire to the ground using a level and program those results into your vehicle using a Tazer JL Mini or similar device. The printed measurement on the tires are not true to their actual size in most cases. If you change gears you will have to program those in as well. This will have a bearing on your MPG's if it's not programmed correctly. I had my gearing and lift done at Trail Jeeps in Golden Co.

 

[Zissou]

It's a dollar cheaper than 93 here.

In the corn belt it's super cheap.

E-85 gives great power, smoothness, and runs cooler.

People cannot wrap their heads around this lol

The corn juice did some amazing things for the V8 mustangs when tuned for it. Mustang6g.com loves e85. Worse mpg, but huge power gains. Like 100 hp from that corn-tune

 

[InvertedLogic]

So 4 and 5 together weigh less than a typical American adult male........ not bad at all!

Indeed. It's a pretty light n fast setup! Not the most feature packed or extravagant, but great for tossing on the truck and jetting out for the weekend.

 

[ShadowsPapa]

Also make sure that you've measured your tires from the top of the tire to the ground using a level and program those results into your vehicle using a Tazer JL Mini or similar device.

That's a starting point. When checked in detail, it may be "ok" or may be off. I started there, then checked ODOMETER against GPS and phone program and found it still was off. So I used jscan to set the tire size again - this time ignoring what I measured and the next time it was perfect.
The physical measurement should be a starting point only - not always a "put it in and it will be fine" stopping point.


For lurkers -
Any software like jscan or AlfaOBD, or a tazer type device can do the plugging in of the tire size, but if one stops with the first number put in assuming it's right because that's what they measured - it may not be correct and could be the reason things are off.

ALWAYS double-check your odometer against a real dedicated GPS and/or phone with GPS software that measures distance in tenths of miles driven.
IF you go by speedometer only you may still be very off because the Jeep speedometer only gives round numbers. That means it could be way off in a distance of 100 miles throwing even manual mpg calculations into the toilet.

 

[ShadowsPapa]

People cannot wrap their heads around this lol

The corn juice did some amazing things for the V8 mustangs when tuned for it. Mustang6g.com loves e85. Worse mpg, but huge power gains. Like 100 hp from that corn-tune

Even a "from the factory" flex fuel LS engine gained something like 15-20 hp just going to E85.
I've known a couple of guys who built their old-skool engines to run on E85 (boosting compression, different cam, totally re-jetting the carburetors) and gained crazy power.

 

[WAOverlandJT]

Update from today. I found the tazer was not keeping my changes after I had set the tires. I also found that my screws were not tightened down on my air filter box. While I doubt the screws had an impact it was something I fixed.

Now that the tazer is fixed and tire setting is saving, it’s hunting gears less and mpg climbing according to the trip computer. I verified the tire setting with a gps app also. I will check manually next fill up.

The bad…. Wife filled the Jeep up with premium gas. So that is also in the changes above and will have an impact.

 

[ShadowsPapa]

Update from today. I found the tazer was not keeping my changes after I had set the tires. I also found that my screws were not tightened down on my air filter box. While I doubt the screws had an impact it was something I fixed.

Now that the tazer is fixed and tire setting is saving, it’s hunting gears less and mpg climbing according to the trip computer. I verified the tire setting with a gps app also. I will check manually next fill up.

The bad…. Wife filled the Jeep up with premium gas. So that is also in the changes above and will have an impact.

It takes a while for the change in gas to have an impact. It won't be immediate, may not even notice it much in the first tank.

 

[shrinkhead]

Rubicon 35 trail grapplers on Mopar lift I got 13.5 mixed city/interstate with the V6 gasser. Only way to improve that was to not drive in city and not go over 60MPH. some stuff you see here for MPGs are either specific to those folks areas or not true.

 

[ShadowsPapa]

Air temperature, speed, terrain, all make big differences. The driver's foot is also one very big part of the equation.
My wife and I have both noticed drops in mpg as the weather has cooled. And on every trip we've made, including today going to Overland Park KS and back, speed was a huge factor. 73 mph sucked mpg-wise, but going down to 65 I could see a difference. Then when we got into traffic near Des Moines with even lower limits- mpg climbed even more.

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