Jeep Wrangler Forum

Jeep Wrangler Forum (http://www.wranglerforum.com/)
-   TJ General Discussion Forum (http://www.wranglerforum.com/f282/)
-   -   Gas Mileage Question (http://www.wranglerforum.com/f282/gas-mileage-question-264998.html)

jrcnova 08-24-2013 09:42 AM

New to the forum and to Jeeps. Just bought a 2000 TJ 4.0, 5 speed with a 4" lift and 35x12.50/15. I scoured the forums to figure out how I can determine my gas mileage. Correct me if I'm wrong but the following equation is what I've found.

Current tire diameter / original tire diameter = answer

Answer X odometer mileage = actual mileage driven

Actual miles driven / number of gallons purchased = mpg

So with that said here's what I've come up with:

35/27.7=1.263537906

1.263537906 X 165.5 = 209.11

209.11/11.392 = 18.36 mpg

Correct?

Jerry Bransford 08-24-2013 09:54 AM

That's a lot of math to arrive at the same answer given by simply dividing the number of miles driven since the last fill-up by the number of gallons required to refill the tank which provides the mpg.

Test4Echo 08-24-2013 09:59 AM

Quote:

Originally Posted by Jerry Bransford (Post 4115167)
That's a lot of math to arrive at the same answer given by simply dividing the number of miles driven since the last fill-up by the number of gallons required to refill the tank which provides the mpg.

Unless he has a pro cal or similar you can't use that equation because the mileage will not be accurate.

Jerry Bransford 08-24-2013 10:06 AM

If the speedometer is reasonably accurate or has been recalibrated after changing the tire diameter, the mileage shown on the odometer is accurate enough for 99.999% of us wanting to know our mpg.

flflash 08-24-2013 10:10 AM

I just don't know why it's so difficult to measure fuel mileage?

Step 1: Use a GPS to verify your speedometer/odometer readings.

Step 2: Fill up with gas. Note odometer reading.

Step 3: Drive vehicle normally until it needs gas again.

Step 4: Refill with gas, noting how many gallons it takes to fill up.

Step 5: Divide gallons of gas used into miles driven.

Step 6: Wonder if driving your Jeep is worth the cost of fuel to operate it.

Step 7: Go on Jeep forums and either Brag about your mileage ( anything over 16 is bragging ) or bemoan how poor your mileage is ( under 15 )

jrcnova 08-24-2013 10:51 AM

My Speedo has not been recalibrated,hence my question.

jrcnova 08-24-2013 10:53 AM

Quote:

Originally Posted by Jerry Bransford (Post 4115167)
That's a lot of math to arrive at the same answer given by simply dividing the number of miles driven since the last fill-up by the number of gallons required to refill the tank which provides the mpg.

The odometer reading will be off because of the 35's. If I was totally stock, your method would be correct.

flflash 08-24-2013 10:55 AM

Quote:

Originally Posted by jrcnova (Post 4115329)
My Speedo has not been recalibrated,hence my question.

Step 1b: Calibrate speedometer or use GPS to track miles driven.

Jerry Bransford 08-24-2013 11:00 AM

Quote:

Originally Posted by jrcnova (Post 4115336)
The odometer reading will be off because of the 35's. If I was totally stock, your method would be correct.

It takes less than five minutes to replace the speedometer gear to get your speedometer accurate again. :)

Atthehop 08-24-2013 11:17 AM

Quote:

Originally Posted by flflash (Post 4115204)
I just don't know why it's so difficult to measure fuel mileage?

Step 1: Use a GPS to verify your speedometer/odometer readings.

Step 2: Fill up with gas. Note odometer reading.

Step 3: Drive vehicle normally until it needs gas again.

Step 4: Refill with gas, noting how many gallons it takes to fill up.

Step 5: Divide gallons of gas used into miles driven.

Step 6: Wonder if driving your Jeep is worth the cost of fuel to operate it.

Step 7: Go on Jeep forums and either Brag about your mileage ( anything over 16 is bragging ) or bemoan how poor your mileage is ( under 15 )


I guess I can brag since I get over 16. LOL

Don02wrangler 09-08-2013 01:56 PM

To Jerry Bransford - I posted a question ealier today.. Is there a speedo drive gear? How would I recalibrate speedo?
THanks!

PStov98TJ 09-08-2013 02:09 PM

Quote:

Originally Posted by Don02wrangler (Post 4396313)
To Jerry Bransford - I posted a question ealier today.. Is there a speedo drive gear? How would I recalibrate speedo?
THanks!

Yes there is. This is how you change it http://www.wranglerforum.com/f105/sp...ge-121033.html


All times are GMT -5. The time now is 05:14 AM.