Gas mileage so far

[BillyHW]

Are you guys doing a manual calculation from the pump as well? How far is the trip computer off from the manual calculation?

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[captainjack]

Are you guys doing a manual calculation from the pump as well? How far is the trip computer off from the manual calculation?

Manual at the the pump. We are within .02.

 

[giangvann]

I have a 2015 JK Sahara and had stock tires before swapping to Rubicon tires/wheels. Mileage dropped from 18-20 mpg to about 15-18. I didn't imagine I'd lose THAT much since the Sahara and Rubicon share the same mileage ratings. Call me naive, but I'm surprised that's acceptable advertising.

 

[BillyHW]

I have a 2015 JK Sahara and had stock tires before swapping to Rubicon tires/wheels. Mileage dropped from 18-20 mpg to about 15-18. I didn't imagine I'd lose THAT much since the Sahara and Rubicon share the same mileage ratings. Call me naive, but I'm surprised that's acceptable advertising.

Did you recalibrate your odometer/speedometer/computer?

 

[giangvann]

Did you recalibrate your odometer/speedometer/computer?

Errrr. Are they not the same tire size? 32's? I figured I didn't need to.

 

[BillyHW]

Errrr. Are they not the same tire size? 32's? I figured I didn't need to.

You're right. I just checked and the diameter is the same even though rim size is different.

Then what could account for the difference? Is the rolling resistance that much different between the two tires?

 

[Dynomite1371]

I'll fill up tomorrow and know for sure, looks like 18 with a lot of highway @70mph..

 

[AZCrawl]

Around 18, with a mix.

 

[giangvann]

You're right. I just checked and the diameter is the same even though rim size is different.

Then what could account for the difference? Is the rolling resistance that much different between the two tires?

My driving hasn't changed, but I'd imagine the rolling resistance to play a huge factor between the A/T and M/T. I'll stick to A/T next time around.

Also, BillyHW, I read everything you're saying in the voice of a freaking out Fry... with the "Ahh!... Gas mileage!" lol.

 

[N2o2he]

First tank 18.2 mixed. Cruise @75 on Interstate. Second tank 16.7 mixed with some trail riding and getting stuck in a mud bog. I’ll take it.

 

[FrenchSSGTMike]

I never thought anybody would actually believe in what they put on window stickers...lol
Pretty sure it’s taken measured downhill, at 40mph, full to the roof, and on bicycle wheels...lol

 

[se7en]

I never thought anybody would actually believe in what they put on window stickers.

USEPA forced the manufacturers to put more realistic numbers on the window stickers a few years back, so we should be able to trust them. My '16 Tacoma was close...actually was lower than what I actually experienced. I'm a little disappointed with my results on the Rubicon based on the 1st tank, mind you. I'm a good 1.5 - 2 MPG lower.

 

[captainjack]

I have a 2015 JK Sahara and had stock tires before swapping to Rubicon tires/wheels. Mileage dropped from 18-20 mpg to about 15-18. I didn't imagine I'd lose THAT much since the Sahara and Rubicon share the same mileage ratings. Call me naive, but I'm surprised that's acceptable advertising.

Do you think that the rubicon wheels only made a difference on mine? I have a Sport and am using the stock tires that come with the limited slip the all terrain instead of the all season?

 

[StyleGuy]

If you’re using a gas/ethanol blend it’s going to have a negative effect on mileage. Around here 10% blend is everywhere and pure 100% gas harder to find. It’ll account for a couple of miles per gallon difference. What are you using?

 

[The Great Grape Ape]

Then what could account for the difference? Is the rolling resistance that much different between the two tires?

Yes. The Duellers are mild rolling-resistance AT tyres, the KMs have much higher resistance (which is typical for MTs). The JK Rubi KM tire combo (tyre+rim) are also slightly heavier too.

As for the rating, especially in the JK where you had 3 axle ratios, 3 trim weight classes, 2 different tops (3 in the JL), multiples tyre options (all before Special Editions), certifying for all combos is unrealistic.

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