What gas milage are you getting?

[Jeeperjamie]

Yes, set to actual size. I rarely see 8th. And around town is a lot of stop and go, short trips. And I don’t baby it.

It does seem a little low though, especially since my 03 suburban 2500 with 33s and an 8.1 gets 11-12 avg

I get 18+ on 35 BFg KO2s, a guy I know in the area with a JT on 37 BFG KO2s is getting 17.6 out of his average. He said he has gotten up to 19 on a trip to Florida. I'm not sure what the weigh difference is between a KM2 and a Ko2 but I would imagine not enough to make that kind of impact.

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[Uparms]

17 mph combined, 20-21 on the big highway, 35X12.5 with 4.10s and 8 speed.

Was 24 mph on stock wheels on highway, 75mph.

 

[ShadowsPapa]

I get 18+ on 35 BFg KO2s, a guy I know in the area with a JT on 37 BFG KO2s is getting 17.6 out of his average. He said he has gotten up to 19 on a trip to Florida. I'm not sure what the weigh difference is between a KM2 and a Ko2 but I would imagine not enough to make that kind of impact.

Can't compare only vehicles, it may be the DRIVER that's making the difference. HUGE difference in how I drive. After my PCM update and reset, I've not been as nice with it and I've dropped the mpg substantially. I know the PCM update accounts for some of it, but I can tell just with my "take-offs" how much I'm impacting my mileage.

 

[Jeeperjamie]

Can't compare only vehicles, it may be the DRIVER that's making the difference. HUGE difference in how I drive. After my PCM update and reset, I've not been as nice with it and I've dropped the mpg substantially. I know the PCM update accounts for some of it, but I can tell just with my "take-offs" how much I'm impacting my mileage.

True, I tend to be lighter on the skinny pedal the older I get. I guess about 18 speeding tickets in my first 6yrs of driving and about $620 a month for car insurance when me and my wife first got married broke me of that. Haven't had a ticket in over 10yrs now.

 

[ShadowsPapa]

True, I tend to be lighter on the skinny pedal the older I get. I guess about 18 speeding tickets in my first 6yrs of driving and about $620 a month for car insurance when me and my wife first got married broke me of that. Haven't had a ticket in over 10yrs now.

Man that sounds familiar! The local magistrate knew me on sight and by name........ one of the local highway patrolmen - the same. He'd say "hello, again, Bill".
Been years since a ticket - thankfully, as they are crazy expensive here now!
I was lucky I still had a license, one time it was so bad my insurance agent wanted to have a chat with me.

 

[Jeeperjamie]

Man that sounds familiar! The local magistrate knew me on sight and by name........ one of the local highway patrolmen - the same. He'd say "hello, again, Bill".
Been years since a ticket - thankfully, as they are crazy expensive here now!
I was lucky I still had a license, one time it was so bad my insurance agent wanted to have a chat with me.

Yep, court cost alone will get you these days, in my county $198 for just court cost. A speeding ticket can easily cost you $400. I lost my license a few times, once for a year and I'm lucky not for longer, 152 in a 65 in my old mustang. That one could of gotten ugly.

 

[livewire_3020]

i averaged 19-20 when i first got it. 4.10 gears. average 16ish now with 6 inch lift and 37s.
alot of 70-80mph highway driving

 

[hjdca]

Curious as to the MPG folks are getting and with what models and options.

I'm averaging about 20 MPG now after 3200 miles. JT Rubicon.
Milage was pretty bad at first averaging around 16 till about 1500 miles. Really started improving after that. My avg includes towing a boat, long drives into a headwind and driving with a payload in back.

MPG takes a nose dive big time above 65 mph, towing and strong headwinds. Driving over 45 with the top and doors off causes a significant drop in MPG too.

The gas mileage that the computer gives you is not correct unless the tire size is set exactly right, not approximately. My Rubicon JT came with 33" Falken M/Ts (285/70/17) and the computer was set to 33.08 tire size, however, the tire spec. size for these exact tires from Falken is 32.8. Once this parameter was set properly in my JT computer, my gas mileage when up by 1 or 2 mpg. The dealer or a device like a Tazer is the only way to change the tire setting size.

 

[ShadowsPapa]

The gas mileage that the computer gives you is not correct unless the tire size is set exactly right, not approximately. My Rubicon JT came with 33" Falken M/Ts (285/70/17) and the computer was set to 33.08 tire size, however, the tire spec. size for these exact tires from Falken is 32.8. Once this parameter was set properly in my JT computer, my gas mileage when up by 1 or 2 mpg. The dealer or a device like a Tazer is the only way to change the tire setting size.

Rolling diameter is the only real way to be accurate. Don't use the tire maker's diameter number. It won't be exact, either.
Anyone who doesn't believe that varies - I ask, how do EU cars figure tire pressure without TPMS devices in the tires, eh? ROLLING diameter based on the speed that tire is turning compared to the others. Rolling diameter varies with tire pressure AND tire size so the speed the tire spins will vary, too. Many vehicles there use ITPM - indirect tire pressure monitoring.

Mine is set exactly right from the factory (for my tire pressure)
I compared two other devices to my odometer and speedometer.
So unless someone has changed tire sizes, there's a great chance the JT is giving accurate info.
Mine was - after 13.5 miles my odometer (trip A) lined up EXACTLY with my Garmin GPS and my phone (not connected to the truck, stand-alone.

It's good to double-check, but at least in my case, the bit where at least some "Jeep people" claim: "all Jeep speedometers are off" - is BS.
Mine is proven extremely accurate.
And the mpg on the cluster lines up with my figuring as well.

You can't necessarily take the factory tire size specs and plug them in either - as the rolling diameter can be off. The A/T says "32.8" but they aren't really exacfly that either so if you plug in 32.8" for the Falken A/T tires, you are likely to be off. There's several threads where people here say use that as a staring point only, not the absolute truth.

Over and over here in this forum it's been shown use the factory specified tire size as a starting point only, adjust until the speedometer/odometer matches an independent GPS.

I have yet to plug in my jscan to see what the factory setting on my JT is, but whatever it is, it's a perfect match.

 

[DeezJT]

So far I’m at 13.5mpg on my 35.75” (37x12.5r17) nitto ridge grapplers ALL STREET MILES on my first week since lifting/bigger tires. I do have the max tow package and I’m adding my Zeon winch/PS bumper tomorrow so I’m pretty sure it’ll go down some.

 

[DaleG]

Yes, set to actual size. I rarely see 8th. And around town is a lot of stop and go, short trips. And I don’t baby it.

It does seem a little low though, especially since my 03 suburban 2500 with 33s and an 8.1 gets 11-12 avg

I had a 03 2500 4wd suburban with the 8.1......it got 11-12 when it wasn’t running.....it would pass everything but a gas station!

 

[hjdca]

Rolling diameter is the only real way to be accurate. Don't use the tire maker's diameter number. It won't be exact, either.
Anyone who doesn't believe that varies - I ask, how do EU cars figure tire pressure without TPMS devices in the tires, eh? ROLLING diameter based on the speed that tire is turning compared to the others. Rolling diameter varies with tire pressure AND tire size so the speed the tire spins will vary, too. Many vehicles there use ITPM - indirect tire pressure monitoring.

Mine is set exactly right from the factory (for my tire pressure)
I compared two other devices to my odometer and speedometer.
So unless someone has changed tire sizes, there's a great chance the JT is giving accurate info.
Mine was - after 13.5 miles my odometer (trip A) lined up EXACTLY with my Garmin GPS and my phone (not connected to the truck, stand-alone.

It's good to double-check, but at least in my case, the bit where at least some "Jeep people" claim: "all Jeep speedometers are off" - is BS.
Mine is proven extremely accurate.
And the mpg on the cluster lines up with my figuring as well.

You can't necessarily take the factory tire size specs and plug them in either - as the rolling diameter can be off. The A/T says "32.8" but they aren't really exacfly that either so if you plug in 32.8" for the Falken A/T tires, you are likely to be off. There's several threads where people here say use that as a staring point only, not the absolute truth.

Over and over here in this forum it's been shown use the factory specified tire size as a starting point only, adjust until the speedometer/odometer matches an independent GPS.

I have yet to plug in my jscan to see what the factory setting on my JT is, but whatever it is, it's a perfect match.

Factory Specs --- the 285/70R17 Falken Wildpeak M/T has a diameter of 32.8", a width of 11", mounts on a 17" rim and has 634 revolutions per mile.

One mile is 63360 inches. Divide 634 into that and you get 99.93 inches per revolution for circumference - Divide 99.93 by 3.14 and you get - 31.8 inches for the diameter -- which seems way off I guess.... one whole inch less than stated diameter...

 

[ShadowsPapa]

Factory Specs --- the 285/70R17 Falken Wildpeak M/T has a diameter of 32.8", a width of 11", mounts on a 17" rim and has 634 revolutions per mile.

One mile is 63360 inches. Divide 634 into that and you get 99.93 inches per revolution for circumference - Divide 99.93 by 3.14 and you get - 31.8 inches for the diameter -- which seems way off I guess.... one whole inch less than stated diameter...

You are going by measured, not rolling diameter. That's different and varies with inflation.
You are also rounding.
Have you read all of the other posts - dozens of them -stating the factory number is a starting point? Search, there's a lot of them, and a lot of folks who used that "factory number" and still had to tweak it.
That's because that's just a "stated number" and not always fact, plus again, rolling diameter is different.
I've seen countless posts here stating, once again, that number is a starting point, not a hard/fast rule.
Look for 'em.....
If it works for you, great, I'm happy for you - but then you are discounting the countless people here who could not go by that number.

 

[hjdca]

You are going by measured, not rolling diameter. That's different and varies with inflation.
You are also rounding.
Have you read all of the other posts - dozens of them -stating the factory number is a starting point? Search, there's a lot of them, and a lot of folks who used that "factory number" and still had to tweak it.
That's because that's just a "stated number" and not always fact, plus again, rolling diameter is different.
I've seen countless posts here stating, once again, that number is a starting point, not a hard/fast rule.
Look for 'em.....
If it works for you, great, I'm happy for you - but then you are discounting the countless people here who could not go by that number.

ok, thanks. I will take your advice and check against GPS and the factory settings. I agree the 33.08 factory computer setting is probably correct.

 

[Blade1668]

Well my "JT" MPG reads that I get around 23 + MPG normally, but I know that the speed is off 1 mile faster than actual speed. I'm on a short trip with my trailer and 4wheeler mpg took a big hit I-State speed pulling it down to about 16.2 MPG not factoring in odometer /speedometer being off a mile. Not quite as bad as some here just lifting and larger tire. I didn't take that much of MPG loss with my 4.0 Jeeps pulling a trailer unless it was close to max load.
A strange thing is the odometer reading normally about dead on with GPS distance just the speed reads faster than actual speed.

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