Will Re-Gearing Pay for Itself in MPG

[Kiwi TJ]

 

[JMT]

Right, but, shorter gears can extend the life of an auto transmission, or a clutch. You gotta work the longevity angle for all its worth.

Well said. I was curious about wear and tear on other components due to improper gearing!

 

[JMT]

View attachment 42096

$10 for the girlfriend? We can see where that relationship is going. Might as well cut your losses and move the $10 up to the Jeep fund.

Your priceless @Kiwi TJ

 

[JMT]

this is probably reason #687 why I'm divorced



justification shmustification, man you know why you are going to do this, you know why it's the right thing to do & you know you're at the stage of the game where you have no reason (good or imagined) not to. You only live once brutha, don't spend another minute with an improperly geared TJ

Are you a philosopher? Comedian? Or all rolled into one? Good call! Definitely cracking me up!

 

[Kiwi TJ]

$10 for the girlfriend? We can see where that relationship is going. Might as well cut your losses and move the $10 up to the Jeep fund.

Your priceless @Kiwi TJ

And I wonder why I'm single :thinking: lol ( happily I might add )

 

[JMT]

And I wonder why I'm single :thinking: lol ( happily I might add )

You got the Jeepfriend. You’re clearly not single and definitely smitten.

 

[Kiwi TJ]

You got the Jeepfriend. You’re clearly not single and definitely smitten.
View attachment 42113

hahaha yes guilty...love at first sight lol and still cost less that my ex

 

[Rubicon]

Depending on where you go in the gear ratio, you should see improvement. The charts recommend 5.38 for that engine and 33" tires.
Calculate your mileage now (fwy performance, and street performance). Then recalc when you've made the mod. If you're 12-14 now, you may probably get 14-15 after the re-gear.

Keep in mind that moving mass - in this case significantly larger tires - requires energy. Force = mass x acceleration. In most cases, energy is lost in the differential, due to mismatched gearing vs. load. You'll never increase gas mileage beyond the design-optimized factory Jeep (which is about 17-18 mpg). But if nothing else changes, all the engineering done on this says you'll convert energy better into the tires. You're looking to reduce the loss, not increase the gain (if that makes sense).

 

[Leinhit]

I just drive in a lower gear, seems easier that re gearing.

I use 5th only when hitting 65 ish.

2001 TJ, 4.0, 3.73 gears with 33" tires.

Sent from my XT1575 using Tapatalk

 

[jjvw]

I just drive in a lower gear, seems easier that re gearing.

I use 5th only when hitting 65 ish.

2001 TJ, 4.0, 3.73 gears with 33" tires.

Sent from my XT1575 using Tapatalk

Having done that for several years and then later regeared, just driving in a lower gear and avoiding OD is not the same as having the power band in a better position across all the available gears.

 

[Jerry Bransford]

I just drive in a lower gear, seems easier that re gearing.

I use 5th only when hitting 65 ish.

2001 TJ, 4.0, 3.73 gears with 33" tires.

While not regearing is obviously easier than regearing your axles is, that's not something experienced Jeepers would recommend. When you start off in 1st gear that's like starting off in 2nd gear with proper gearing which is also harder on the clutch. You're just trying to overcome the misgearing by not shifting normally, you'd kick yourself for not having regeared sooner if you ever did regear to the proper ratio. Your engine is seldom operating at its most efficient rpms. You might even pick up a couple additional mpg by regearing to get your engine back up into its power band. I went to slightly under 12 mpg to nearly 15 mpg after regearing from 4.88 to 5.38 for my 35" tires with my 42RLE automatic transmission. Not to mention the engine just runs better and the transmission even shifts more appropriately... especially when on the highway.

 

[bobthetj03]

Let's also not forget how much nicer it is offroad in 4Lo when creeping over an obstacle or 4. That is where re-gearing to the proper ratio really shines.

 

[jjvw]

Let's also not forget how much nicer it is offroad in 4Lo when creeping over an obstacle or 4. That is where re-gearing to the proper ratio really shines.

This fits in with my belief that if you build your Jeep to perform and behave well on pavement, then it will carry over to the trail.

 

[Jerry Bransford]

This fits in with my belief that if you build your Jeep to perform and behave well on pavement, then it will carry over to the trail.

X2 and even more importantly, being undergeared can make drivetrain damage more likely. How you say? Because being undergeared increases the crawl speed, often making the speed in 4Lo too fast to maintain adequate control during difficult trail conditions. The tougher the trail, the more being misgeared hurts you.

 

[Rob5589]

I just drive in a lower gear, seems easier that re gearing.

I use 5th only when hitting 65 ish.

2001 TJ, 4.0, 3.73 gears with 33" tires.

A re-gear does more than allow you to use your top gear.

X2 and even more importantly, being undergeared can make drivetrain damage more likely. How you say? Because being undergeared increases the crawl speed, often making the speed in 4Lo too fast to maintain adequate control during difficult trail conditions. The tougher the trail, the more being misgeared hurts you.

Agree. Nothing better than pointing her downhill and letting the low gearing do its thing. Staying off the brakes is key to keeping it pointed straight and where it belongs.

 

[Leinhit]

X2 and even more importantly, being undergeared can make drivetrain damage more likely. How you say? Because being undergeared increases the crawl speed, often making the speed in 4Lo too fast to maintain adequate control during difficult trail conditions. The tougher the trail, the more being misgeared hurts you.

All Points well-taken although a lot of talk of a lot of off-roading where is I probably sit in the majority that drive it on the road mostly and occasionally go on a somewhat maintained Trail, no rock crawling for me.

Let me ask you this, yesterday I tested it a bit at 65 miles an hour in 5th gear I am pulling 2000 RPMs. Do you consider that too low of an RPM and what is the ideal RPM range for that speed?

Yes I do have to drop down into 4th gear to pass anybody on a two-lane road or going up hills.

I take off in first gear all the time and never feel as though it's lagging or struggling in fact I shift out of first fairly quick because I used it all up.

I'm all for having a better driving experience, I'm not sure if the answer is going to 410 or 411 gears from 373 is worth the cost vs The Experience?

Thanks

Sent from my XT1575 using Tapatalk

 

[Mr. Bills]

To Leinhit:

Your rpms at 65 mph in 5th gear are a bit below the 2,400-2,700 rpm "sweet spot," but in my opinion not so low as to justify the expense of re-gearing based on how you actually use your jeep and your lack of any objection to downshifting to 4th when necessary. However, if you ever go to larger tires you should revisit the subject.

 

[Rob5589]

All Points well-taken although a lot of talk of a lot of off-roading where is I probably sit in the majority that drive it on the road mostly and occasionally go on a somewhat maintained Trail, no rock crawling for me.

Let me ask you this, yesterday I tested it a bit at 65 miles an hour in 5th gear I am pulling 2000 RPMs. Do you consider that too low of an RPM and what is the ideal RPM range for that speed?

Yes I do have to drop down into 4th gear to pass anybody on a two-lane road or going up hills.

I take off in first gear all the time and never feel as though it's lagging or struggling in fact I shift out of first fairly quick because I used it all up.

I'm all for having a better driving experience, I'm not sure if the answer is going to 410 or 411 gears from 373 is worth the cost vs The Experience?

Thanks

Sent from my XT1575 using Tapatalk

Yes, 2000 is below the more workable rpms, roughly 2500. Going from 3.73 to 4.10 would not be worth the money. If you are satisfied with the performance of your Jeep, then don't worry about a gear swap.

 

[Leinhit]

Thanks..

I wouldn't be opposed to it but for what money, and I have no idea what it cost to re gear,. $1500? , I d probably rather do some other mods for the time being.

Appreciate the sweet spot rpm info.

Thanks for a common sense answer without any detected "tone" in it [emoji16]

To Leinhit:

Your rpms at 65 mph in 5th gear are a bit below the 2,400-2,700 rpm "sweet spot," but in my opinion not so low as to justify the expense of re-gearing based on how you actually use your jeep and your lack of any objection to downshifting to 4th when necessary. However, if you ever go to larger tires you should revisit the subject.

Sent from my XT1575 using Tapatalk

 

[Leinhit]

Yes, 2000 is below the more workable rpms, roughly 2500. Going from 3.73 to 4.10 would not be worth the money. If you are satisfied with the performance of your Jeep, then don't worry about a gear swap.

Thank you sir! Appreciate it.

Sent from my XT1575 using Tapatalk