Will Re-Gearing Pay for Itself in MPG

[JMT]

I want to know how much of an effect re-gearing your TJ had on your MPG. My current setup is 4.0, 3.73, 6-speed, 33's. I remember @Jerry Bransford got an increase in his MPG when he went to 5.38. I was figuring maybe 2-3MPG as a reasonable estimate. If that's the case, with my annual mileage and current gas prices, I can save ~$300/year. That would mean that in 5 years the re-gearing would pay for itself. If gas prices go up, it would pay for itself even faster. Is this a reasonable expectation and another good argument for re-gearing?

 

[lowranger]

I want to know how much of an effect re-gearing your TJ had on your MPG. My current setup is 4.0, 3.73, 6-speed, 33's. I remember @Jerry Bransford got an increase in his MPG when he went to 5.38. I was figuring maybe 2-3MPG as a reasonable estimate. If that's the case, with my annual mileage and current gas prices, I can save ~$300/year. That would mean that in 5 years the re-gearing would pay for itself. If gas prices go up, it would pay for itself even faster. Is this a reasonable expectation and another good argument for re-gearing?

If that's what you want to tell your wife so you can re-gear.....go ahead.

 

[Mr. Bills]

The reason to re-gear is to match gearing to changes in tire size . Minor decreases in fuel consumption by keeping the engine in its power band rather than lugging it are an additional benefit of re-gearing, but trying to rationalize the expense with theoretical reductions in fuel cost over time is a fool's game. Besides, your real world mpg's may actually go down a bit because you will be having too much fun tromping on the gas and enjoying your restored performance.

 

[Chris]

If that's what you want to tell your wife so you can re-gear.....go ahead.

Haha, I was about to say the same thing.

I was going to say that @JMT is trying to find every excuse he can to justify the cost of re-gearing. This is how you know you're a hardcore Jeeper!

In all seriousness though @JMT, when I had my old Rubicon re-geared, I definitely felt a difference, but I never once paid attention to whether or not the mpg was better. I will say that with that old Rubicon I achieved a record of 22 mpg on the highway on a 200 mile road trip, so I have to assume that was due to the proper gearing ratio. I don't think I could have done that before, especially since that 22 mpg was on 33" tires with a 4" lift!

 

[jjvw]

I haven't kept up on the mileage as well as I used to. Since the regear, I do feel like my mileage has evened out. The highs aren't as high, the lows aren't as low. I have a sense that there is a small overall increase. The speedo was very accurate both before and after.

Really, the most important benefit is that the Jeep is just so much nicer to drive with lower axle gearing.

 

[JMT]

If that's what you want to tell your wife so you can re-gear.....go ahead.

Someone knows how to read between the lines.

 

[xxdabroxx]

That's about equivalent to buying a motorcycle to save money on gas.

 

[bobthetj03]

I averaged 13.4 MPG's before the re-gear, and 13.7 MPG's after the re-gear. Not enough to justify it just on mileage performance. Sorry brah. My smiles per gallon increased substantially though!

 

[xxdabroxx]

I couldn't tell you MPG difference but I went from never using 4-5 gear to rarely using first gear after I regeared. My clutch thanks me. 2nd seems equivalent to about what 1st used to be. It's a lot more fun to drive that's for sure.

 

[jjvw]

That's about equivalent to buying a motorcycle to save money on gas.

I did this, more or less. Last year I bought a used Honda Ruckus to get around town hoping to save on gas. That worked, but I also couldn't stop myself from modifying the Ruckus. It was a hopeless endeavor...

 

[jjvw]

I couldn't tell you MPG difference but I went from never using 4-5 gear to rarely using first gear after I regeared. My clutch thanks me. 2nd seems equivalent to about what 1st used to be. It's a lot more fun to drive that's for sure.

One of the things a really enjoy about my new 1st gear is being able to very slowly and steadily idle along with rush hour traffic.

 

[xxdabroxx]

One of the things a really enjoy about my new 1st gear is being able to very slowly and steadily idle along with rush hour traffic.

Works great at stop signs with a long line for me, not much traffic or freeways around here.

 

[Nathan Stanfield]

Strange as it sounds I got 14 mpg with 3.07 gears with 33's and now that I have 4.10 gears with the same tires I'm still right around 13.5 - 14 mpg.
Maybe it has to do with the weather being warmer.

 

[Rob5589]

Absolutely, Mrs. JMT! You'll be amazed at the fuel savings. Easily enough to pay for a nice family vacation in a short 5 years, and a spa day for you!











There, hope that helps

 

[KCsTJ]

Someone knows how to read between the lines.

That was my 1st thought... if you can justify the cost with math n stuff, that should get a big thumbs up from the wifey!

 

[biggrigg49]

I went from 3.07 on 33's to 4.56 on 33's. No noticeable change in mileage but a lot more fun to drive. I get 13-14 mpg on a 4" lift.

 

[jchadscud]

That was my 1st thought... if you can justify the cost with math n stuff, that should get a big thumbs up from the wifey!

Add a graph and some percentage increase stats to your presentation if you really want to close the sale!

 

[jjvw]

Add a graph and some percentage increase stats to your presentation if you really want to close the sale!

Yes! Women love charts!

 

[Alex01]

Like many others here I did not see any noteworthy improvement on fuel consumption when I switched from 4.10 to 4.88. As far a performance goes though it was night and day.

 

[Jerry Bransford]

There are several reasons to regear but savings from an increase in mpg is definitely not one of them. My mpg went up about 3 mpg after I regeared to 5.38 to eliminate the engine lugging but I'll be long dead and buried before that slight increase would pay for regearing a Jeep. That surprising and substantial increase in mpg was just a little additional icing on the cake.

I just came back from another long trip out to the desert and I was hauling ass to get there (naturally ) so when the traffic was flowing at 75-80 in a few spots and I was staying with it, I thought there went my mpg increase. Nope, it was 14.93 mpg (the calc result was still on my phone) and I was shocked. One of these days I'll try to hold it to no faster than 65 and see what I get.