Big Tires vs MPG
JK Super Freak
Joined: Sep 2007
Posts: 1,623
Likes: 5
From: Lawrenceville, NJ
Is that with a re-calibrated speedometer/odometer?
Or did you just drive 13.5% slower than the speedometer said you were going, like, if you wanted to go 65 mph, did you drive at an indicated 56 mph?
When getting gas, did you add 14% to the odometer reading to correct back the 13.5% low it indicated?
Of did you drive at 74 mph, and use the lower odometer reading to calculate mpg...
....or just get the same combination of errors with the mpg gauge on the dash?
I ask, because I'm trying to collect percentages of how people calculated what mpg they got...the most common issue was driving a lot faster than they normally would...as its human nature to see a 65 mph speed limit sign, and if the speedometer SAYS they are going 65, or whatever they feel they want to get away with....they drive at that INDICATED speed....rather than do the math to drive the ACTUAL speed, etc.
So, be honest, this is for posterity.
Or did you just drive 13.5% slower than the speedometer said you were going, like, if you wanted to go 65 mph, did you drive at an indicated 56 mph?
When getting gas, did you add 14% to the odometer reading to correct back the 13.5% low it indicated?
Of did you drive at 74 mph, and use the lower odometer reading to calculate mpg...
....or just get the same combination of errors with the mpg gauge on the dash?
I ask, because I'm trying to collect percentages of how people calculated what mpg they got...the most common issue was driving a lot faster than they normally would...as its human nature to see a 65 mph speed limit sign, and if the speedometer SAYS they are going 65, or whatever they feel they want to get away with....they drive at that INDICATED speed....rather than do the math to drive the ACTUAL speed, etc.
So, be honest, this is for posterity.
JK Junkie
Joined: Oct 2007
Posts: 2,361
Likes: 0
From: Montana
Is that with a re-calibrated speedometer/odometer?
Or did you just drive 13.5% slower than the speedometer said you were going, like, if you wanted to go 65 mph, did you drive at an indicated 56 mph?
When getting gas, did you add 14% to the odometer reading to correct back the 13.5% low it indicated?
Of did you drive at 74 mph, and use the lower odometer reading to calculate mpg...
....or just get the same combination of errors with the mpg gauge on the dash?
I ask, because I'm trying to collect percentages of how people calculated what mpg they got...the most common issue was driving a lot faster than they normally would...as its human nature to see a 65 mph speed limit sign, and if the speedometer SAYS they are going 65, or whatever they feel they want to get away with....they drive at that INDICATED speed....rather than do the math to drive the ACTUAL speed, etc.
So, be honest, this is for posterity.
Or did you just drive 13.5% slower than the speedometer said you were going, like, if you wanted to go 65 mph, did you drive at an indicated 56 mph?
When getting gas, did you add 14% to the odometer reading to correct back the 13.5% low it indicated?
Of did you drive at 74 mph, and use the lower odometer reading to calculate mpg...
....or just get the same combination of errors with the mpg gauge on the dash?
I ask, because I'm trying to collect percentages of how people calculated what mpg they got...the most common issue was driving a lot faster than they normally would...as its human nature to see a 65 mph speed limit sign, and if the speedometer SAYS they are going 65, or whatever they feel they want to get away with....they drive at that INDICATED speed....rather than do the math to drive the ACTUAL speed, etc.
So, be honest, this is for posterity.
AEV recalibrated the speedo and its right on with my GPS.
JK Enthusiast
Joined: Feb 2007
Posts: 199
Likes: 0
Agreed!
I run 35" tires now.
My Jeep turned into a pig.
Well not a PIG but a goat.
IT'sA GOAT!
MPG dropped a lot from stock.
Also get up and go went bye bye.
I knew that before i done it tho so I wasn't shocked.
Just SAD that to have my fun I have to melt down the earth...
Still I average about 14mpg on most trail'n trips. Which I consider to be EXCELLENT and was pleasantly surprised. The comination of slower speeds and 4w drive seems to work out pretty well.
Where it kinda sucks is city driving as I don;t do any better than the same 14mpg. Fortunately it isn't my DD so that really isn't an issue for me.
Freeway milage is anywhere from 17 to 20mpg depending on conditions.
Uphill 17 (steeply uphill prolly 14 and very piggynessish)
Into a head wind 17
Flat and no wind 20
Flat and a nice strong tail wind 21 or 22 but thats so rare I only seen it once.
Before I put on the 35s I was getting 18/19 in the city and 23 on the freeway.
This is a 4spd automatic with the 4.1 gearing.
I run 35" tires now.
My Jeep turned into a pig.
Well not a PIG but a goat.
IT'sA GOAT!
MPG dropped a lot from stock.
Also get up and go went bye bye.
I knew that before i done it tho so I wasn't shocked.
Just SAD that to have my fun I have to melt down the earth...
Still I average about 14mpg on most trail'n trips. Which I consider to be EXCELLENT and was pleasantly surprised. The comination of slower speeds and 4w drive seems to work out pretty well.
Where it kinda sucks is city driving as I don;t do any better than the same 14mpg. Fortunately it isn't my DD so that really isn't an issue for me.
Freeway milage is anywhere from 17 to 20mpg depending on conditions.
Uphill 17 (steeply uphill prolly 14 and very piggynessish)
Into a head wind 17
Flat and no wind 20
Flat and a nice strong tail wind 21 or 22 but thats so rare I only seen it once.
Before I put on the 35s I was getting 18/19 in the city and 23 on the freeway.
This is a 4spd automatic with the 4.1 gearing.
JK Super Freak
Joined: Sep 2007
Posts: 1,623
Likes: 5
From: Lawrenceville, NJ
Agreed!
I run 35" tires now.
My Jeep turned into a pig.
Well not a PIG but a goat.
IT'sA GOAT!
MPG dropped a lot from stock.
Also get up and go went bye bye.
I knew that before i done it tho so I wasn't shocked.
Just SAD that to have my fun I have to melt down the earth...
Still I average about 14mpg on most trail'n trips. Which I consider to be EXCELLENT and was pleasantly surprised. The comination of slower speeds and 4w drive seems to work out pretty well.
Where it kinda sucks is city driving as I don;t do any better than the same 14mpg. Fortunately it isn't my DD so that really isn't an issue for me.
Freeway milage is anywhere from 17 to 20mpg depending on conditions.
Uphill 17 (steeply uphill prolly 14 and very piggynessish)
Into a head wind 17
Flat and no wind 20
Flat and a nice strong tail wind 21 or 22 but thats so rare I only seen it once.
Before I put on the 35s I was getting 18/19 in the city and 23 on the freeway.
This is a 4spd automatic with the 4.1 gearing.
I run 35" tires now.
My Jeep turned into a pig.
Well not a PIG but a goat.
IT'sA GOAT!
MPG dropped a lot from stock.
Also get up and go went bye bye.
I knew that before i done it tho so I wasn't shocked.
Just SAD that to have my fun I have to melt down the earth...
Still I average about 14mpg on most trail'n trips. Which I consider to be EXCELLENT and was pleasantly surprised. The comination of slower speeds and 4w drive seems to work out pretty well.
Where it kinda sucks is city driving as I don;t do any better than the same 14mpg. Fortunately it isn't my DD so that really isn't an issue for me.
Freeway milage is anywhere from 17 to 20mpg depending on conditions.
Uphill 17 (steeply uphill prolly 14 and very piggynessish)
Into a head wind 17
Flat and no wind 20
Flat and a nice strong tail wind 21 or 22 but thats so rare I only seen it once.
Before I put on the 35s I was getting 18/19 in the city and 23 on the freeway.
This is a 4spd automatic with the 4.1 gearing.
___________________
I ask the same questions as above - re-calibrated, etc?
JK Enthusiast
Joined: Jan 2008
Posts: 250
Likes: 0
From: Hampton, VA
With what I've got, I usually have around 15 on the highway and 13-14 in the city. But, I just got back from a wheelin' trip and actually averaged 17 mpg... I think this means I need to drive off road more often 
JK Enthusiast
Joined: Sep 2007
Posts: 105
Likes: 0
From: Texas
Haven't lifted mine yet.
But on the gas price outrage and Americans "taking" it.
You would be shocked to learn we have some of the cheapest gas on the Earth. Most of the world is paying about 12 dollars per gallon.
The only two execptions I know of are Saudi Arabia, and Venezuala.
But on the gas price outrage and Americans "taking" it.
You would be shocked to learn we have some of the cheapest gas on the Earth. Most of the world is paying about 12 dollars per gallon.
The only two execptions I know of are Saudi Arabia, and Venezuala.
Netherlands Amsterdam $6.48
Norway Oslo $6.27
Italy Milan $5.96
Denmark Copenhagen $5.93
Belgium Brussels $5.91
Sweden Stockholm $5.80
United Kingdom London $5.79
Germany Frankfurt $5.57
France Paris $5.54
Portugal Lisbon $5.35
Hungary Budapest $4.94
Luxembourg $4.82
Croatia Zagreb $4.81
Ireland Dublin $4.78
Switzerland Geneva $4.74
Spain Madrid $4.55
Japan Tokyo $4.24
Czech Republic Prague $4.19
Romania Bucharest $4.09
Andorra $4.08
Estonia Tallinn $3.62
Bulgaria Sofia $3.52
Brazil Brasilia $3.12
Cuba Havana $3.03
Taiwan Taipei $2.84
Lebanon Beirut $2.63
South Africa Johannesburg $2.62
Nicaragua Managua $2.61
Panama Panama City $2.19
Russia Moscow $2.10
Puerto Rico San Juan $1.74
Saudi Arabia Riyadh $0.91
Kuwait Kuwait City $0.78
Egypt Cairo $0.65
Nigeria Lagos $0.38
Venezuela Caracas $0.12
JK Freak
Joined: May 2007
Posts: 527
Likes: 0
From: frisco, tx
Here is how i calculate my MPG:
Stock tire size - 225/75/16 - 29.3 diameter; 92.049 circumference
BFG tire size - 35/12.50/15 - 34.8 diameter; 109.327circumference
(109.327-92.049) / (92.049) = .1877 = 18.77%
(# Miles since last Fillup X 1.1877) / (# Gallons at Fillup)
The 18.77% difference agrees with my GPS device.
Stock tire size - 225/75/16 - 29.3 diameter; 92.049 circumference
BFG tire size - 35/12.50/15 - 34.8 diameter; 109.327circumference
(109.327-92.049) / (92.049) = .1877 = 18.77%
(# Miles since last Fillup X 1.1877) / (# Gallons at Fillup)
The 18.77% difference agrees with my GPS device.
JK Enthusiast
Joined: May 2007
Posts: 261
Likes: 0
From: Plainfield, IL
You can't look at at just MPG cost, which will be much higher. Bigger tires can be very heavy, I have seen as much as 45 lbs per tires/wheel. But also you have to see other cost as well, the more obvious one will be your brakes. The JK brakes are not designed for big tires, and unless you add bigger brakes, your braking distance will suffer and you will need to change your brake pads more often. It will also, as mentioned, add stress to your engine and gear box. The Rubicon will do a bit better with bigger tires, but your overall maintenance will suffer.