- let's talk about proper gearing -
05-24-2011, 11:48 AM
#22
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Regearing seems that it can be a huge, expensive process (unless you are a very good mechanic and are tackling the job yourself - I most certainly am not.)
My plan when I go from 33s to 35s is to drive around w/ my lower (3.73) gears for a few weeks after I put the 35s on. If the jeep handles all I need it too, and passes as 'drivable' to me, then I won't regear. If I feel that I need the upgrade, I'll figure out which gears make the most sense.
Depending on your driving, and your personal preference for how the jeep 'feels', you may prefer different gears than someone else may - which can lead to a lot of the confusion that you/me/the next guy reads when looking into regearing and reads many varying bits of advice.
Test driving a local's gears is a great idea, and I'm sure a Dream Girl like yourself will have no trouble making Jeep buddies.
My plan when I go from 33s to 35s is to drive around w/ my lower (3.73) gears for a few weeks after I put the 35s on. If the jeep handles all I need it too, and passes as 'drivable' to me, then I won't regear. If I feel that I need the upgrade, I'll figure out which gears make the most sense.
Depending on your driving, and your personal preference for how the jeep 'feels', you may prefer different gears than someone else may - which can lead to a lot of the confusion that you/me/the next guy reads when looking into regearing and reads many varying bits of advice.
Test driving a local's gears is a great idea, and I'm sure a Dream Girl like yourself will have no trouble making Jeep buddies.
05-24-2011, 12:05 PM
#23
JK Super Freak
Ran 35s with an auto on 3.73s, for 2 years and it was OK but it wasn't great. Got 15mpg. On 5.13s now with 35s, get the same gas mileage, but its so much better on the low end and actually can maintain speed on the highway without all the downshifting. Worth it for sure 
05-24-2011, 12:27 PM
#24
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I ended up with 5.38's on accident (long story) on my Unlimited Automatic with 35's.
Here are my thoughts:
1. It's my DD and I commute 38 miles (19 each way) to work every day, the 5.38's are perfect. RMP's aren't too high (per RMP chart only 115 more than 5.13's) and I have plenty of power to navigate the city streets and merge onto the freeway.
2. I have a 1700 pound boat that I pull on occasion and I'd expect that the 5.38's would work best for me when towing.
3. I have a Rubicon with Dana 44's and if I ever choose to go with 37's the 5.38's would perform better than 5.13's (again, per RPM chart).
I guess at the end of the day what I am getting at is there are certain factors that need to be taken into account when choosing gears. I'm no expert on gearing by any means, but I did get to drive my automatic with 35's and 4.10's and it was absolutely awful. I live in the Bay Area, CA and our highways have plenty of inclines and the 4.10's struggled to keep me in OD.
Now, with the 5.38's my Jeep stays in OD as it should and in my opinion this gear ratio (5.38) drives better than the stock rubicon tires and gears.
You do get some MPG's back and as of right now I am in the 15.6 MPG range. Keep in mind I am running a tuner as well (SC - 91 Performance), so I am not sure what that does to my MPG.
Here are my thoughts:
1. It's my DD and I commute 38 miles (19 each way) to work every day, the 5.38's are perfect. RMP's aren't too high (per RMP chart only 115 more than 5.13's) and I have plenty of power to navigate the city streets and merge onto the freeway.
2. I have a 1700 pound boat that I pull on occasion and I'd expect that the 5.38's would work best for me when towing.
3. I have a Rubicon with Dana 44's and if I ever choose to go with 37's the 5.38's would perform better than 5.13's (again, per RPM chart).
I guess at the end of the day what I am getting at is there are certain factors that need to be taken into account when choosing gears. I'm no expert on gearing by any means, but I did get to drive my automatic with 35's and 4.10's and it was absolutely awful. I live in the Bay Area, CA and our highways have plenty of inclines and the 4.10's struggled to keep me in OD.
Now, with the 5.38's my Jeep stays in OD as it should and in my opinion this gear ratio (5.38) drives better than the stock rubicon tires and gears.
You do get some MPG's back and as of right now I am in the 15.6 MPG range. Keep in mind I am running a tuner as well (SC - 91 Performance), so I am not sure what that does to my MPG.
Last edited by sanjosebass; 05-24-2011 at 02:09 PM.
05-24-2011, 12:46 PM
#25
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I ended up with 5.38's on accident (long story) on my Unlimited Automatic with 35's.
Here are my thoughts:
1. It's my DD and I commute 38 miles (19 each way) to work every day, the 5.38's are perfect. RMP's aren't too high (per RMP chart only 115 more than 5.13's) and I have plenty of power to navigate the city streets and merge onto the freeway.
2. I have a 1700 pound boat that I pull on occasion and I'd expect that the 5.38's would work best for me when towing.
3. I have a Rubicon with Dana 44's and if I ever choose to go with 37's the 5.38's would perform better than 5.13's (again, per RPM chart).
I guess at the end of the day what I am getting at is there are certain factors that need to be taken into account when choosing gears. I'm no expert on gearing by any means, but I did get to drive my automatic with 35's and 4.10's and it was absolutely awful. I live in the Bay Area, CA and our highways aren't flat by any means and the 4.10's struggled to keep me in OD.
Now, with the 5.38's my Jeep stays in OD as it should and in my opinion this gear ratio (5.38) drives better than the stock rubicon tires and gears.
You do get some MPG's back and as of right now I am in the 15.6 MPG range. Keep in mind I am running a tuner as well (SC - 91 Performance), so I am not sure what that does to my MPG.
Here are my thoughts:
1. It's my DD and I commute 38 miles (19 each way) to work every day, the 5.38's are perfect. RMP's aren't too high (per RMP chart only 115 more than 5.13's) and I have plenty of power to navigate the city streets and merge onto the freeway.
2. I have a 1700 pound boat that I pull on occasion and I'd expect that the 5.38's would work best for me when towing.
3. I have a Rubicon with Dana 44's and if I ever choose to go with 37's the 5.38's would perform better than 5.13's (again, per RPM chart).
I guess at the end of the day what I am getting at is there are certain factors that need to be taken into account when choosing gears. I'm no expert on gearing by any means, but I did get to drive my automatic with 35's and 4.10's and it was absolutely awful. I live in the Bay Area, CA and our highways aren't flat by any means and the 4.10's struggled to keep me in OD.
Now, with the 5.38's my Jeep stays in OD as it should and in my opinion this gear ratio (5.38) drives better than the stock rubicon tires and gears.
You do get some MPG's back and as of right now I am in the 15.6 MPG range. Keep in mind I am running a tuner as well (SC - 91 Performance), so I am not sure what that does to my MPG.
What if I want to run 33", how regearing will effect the MPG?
*Stock JKU Rubicon Auto.
05-24-2011, 12:55 PM
#26
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Mpg
I started stock around 21MPG. Then I beefed up to 37's and got 15.5 MPG. I then re-geared to 5.13 and average 17-18~ish. 18.5-19 on my trips to Moab. I'm sure on the trails I am getting 5 or something...
I have a manual transmission and stay pretty light on the pedal. I keep my spare, hi-lift, and trail-tools in the garage when my wife uses it as a daily driver and she gets close to 19 as a DD.
I did notice that when I put in 91 or higher gasoline, I usually get .25-.5MPG more.
The biggest difference you will see in MPG will be from two things: Re-Gearing and driving a jeep the way it's supposed to be driven... Like a granny.
If you keep your oil changed regularly, use synthetic oil, keep your filter clean(air and oil), and keep your jeep light, you will add up a few MPG savings as well.
I have a friend(more an acquaintance) who lives north of me and he rolls 40's on his 4dr 2010, re-geared to 5.38's, and stripped his jeep of ALL EXCESS weight (This included carpet, back seats, swapped for lighter half doors(he almost never has doors on), glove box, center console, among other things), plus he drives SLOW as HELL, and he claims he gets 19-20 on a regular basis.
I have a manual transmission and stay pretty light on the pedal. I keep my spare, hi-lift, and trail-tools in the garage when my wife uses it as a daily driver and she gets close to 19 as a DD.
I did notice that when I put in 91 or higher gasoline, I usually get .25-.5MPG more.
The biggest difference you will see in MPG will be from two things: Re-Gearing and driving a jeep the way it's supposed to be driven... Like a granny.
If you keep your oil changed regularly, use synthetic oil, keep your filter clean(air and oil), and keep your jeep light, you will add up a few MPG savings as well.
I have a friend(more an acquaintance) who lives north of me and he rolls 40's on his 4dr 2010, re-geared to 5.38's, and stripped his jeep of ALL EXCESS weight (This included carpet, back seats, swapped for lighter half doors(he almost never has doors on), glove box, center console, among other things), plus he drives SLOW as HELL, and he claims he gets 19-20 on a regular basis.
05-24-2011, 01:42 PM
#27
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I have 315/70R-17 Duratracs, auto with 3.73s and just re geared to 5.13s. Performance is much better, but I drive like a granny. I will be taking a highway trip this weekend to the beach and can give a better report then, but I can tell you that my mileage gauge (not too accurate I know, but...) showed 10-13 mpg prior to the re gear in town. Now it regularly shows 14-15 mpg. My friend who did the same re gear as me 2 weeks earlier took a trip to Moab and sent me a photo of his dash. 70 mph according to GPS (speed is off until superchips comes out for 2011): rpms were 2500 and mileage gauge showed 17.5 on the highway. That would be awesome if I can get it...report to follow.
