1st post ? about gears/tire size
#1
JK Newbie
Thread Starter
Join Date: Nov 2009
Location: Corpus Christi, TX
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://www.jk-forum.com/forums/images/icons/icon1.gif)
Hello. I am new to this forum, but belong to a few others. Hope I won't get flamed to bad. I did try searching, but could not find the results I was hoping for.
So this being my first Jeep I have a question. I have a 2010 2 door Sport. I want to do the BB lift and 35's. My delima is the gearing from the factory. My window sticker says it has 3.21. I don't really want to go all the way to 4.10 because this is my daily driver and I want to maintain some respectable fuel economy. I dont do much off roading. Mud and sand mainly and never rock crawl. So my long winded question is what gearing would you recomend for 35's that will give me enough power, but still run 75 on the highway and get a decent MPG? Thanks in advance.
So this being my first Jeep I have a question. I have a 2010 2 door Sport. I want to do the BB lift and 35's. My delima is the gearing from the factory. My window sticker says it has 3.21. I don't really want to go all the way to 4.10 because this is my daily driver and I want to maintain some respectable fuel economy. I dont do much off roading. Mud and sand mainly and never rock crawl. So my long winded question is what gearing would you recomend for 35's that will give me enough power, but still run 75 on the highway and get a decent MPG? Thanks in advance.
#2
JK Newbie
Thread Starter
Join Date: Nov 2009
Location: Corpus Christi, TX
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://www.jk-forum.com/forums/images/icons/icon1.gif)
I spoke too soon. I just found a thread that shows the gearing chart for RPM/ tire size. It looks like 5.13 might be best bet?? Also wanted to mention that my Jeep is a standard.
#3
![Default](https://www.jk-forum.com/forums/images/icons/icon1.gif)
I wouldn't run 5.13's personally if you aren't going to be rock climbing.
Try a superchips flashpaq.
I'm running 3.21's with 33's it was a little slow. I updated my tune with the flashpaq and it was way better than stock.
Personally I'd go that route for 300 or so dollars rather than 1000+ to re-gear at which time you'll most likely want the flashpaq anyway to change your axle ratio and tire size to correct your speedo.
So I'd start with that and see how you like it
Try a superchips flashpaq.
I'm running 3.21's with 33's it was a little slow. I updated my tune with the flashpaq and it was way better than stock.
Personally I'd go that route for 300 or so dollars rather than 1000+ to re-gear at which time you'll most likely want the flashpaq anyway to change your axle ratio and tire size to correct your speedo.
So I'd start with that and see how you like it
#4
JK Jedi Master
![FJOTM Winner](https://i.ibb.co/FgFLpFN/Untitled-1.jpg)
Join Date: Jan 2008
Location: Austin <--> Colorado Springs
Posts: 11,465
Likes: 0
Received 162 Likes
on
154 Posts
![Default](https://www.jk-forum.com/forums/images/icons/icon1.gif)
Browse any of the hundreds of gearing threads and you'll find that the suggestions in the FAQ's are pretty universally accurate.
For 35's:
4.88's with a manual (some prefer 4.56 or 5.13)
5.13's with an auto (some prefer 4.88, or 5.38 for those that have rubicons)
With 3.21's, there is no chance of a flashpaq coming close to the performance gain of re-gearing. Will it help? Of course. But nowhere close to gears.
As you've already seen, that chart takes a lot of the 'opinion' out of the decision and puts it into perspective with numbers you can understand and feel...
For 35's:
4.88's with a manual (some prefer 4.56 or 5.13)
5.13's with an auto (some prefer 4.88, or 5.38 for those that have rubicons)
With 3.21's, there is no chance of a flashpaq coming close to the performance gain of re-gearing. Will it help? Of course. But nowhere close to gears.
As you've already seen, that chart takes a lot of the 'opinion' out of the decision and puts it into perspective with numbers you can understand and feel...
Last edited by nthinuf; 12-16-2009 at 07:28 PM.
#5
JK Newbie
Thread Starter
Join Date: Nov 2009
Location: Corpus Christi, TX
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://www.jk-forum.com/forums/images/icons/icon1.gif)
Thanks for the quick suggestions. The more I read the more it is looking like 4.56 would give me the best mix of power and MPG. I live in flat Gulf Coast Tx and really only use the 4WD for some mud and sand getting to fishing holes...I do about 30 mile round trip at 70/75 MPH for work everyday. Am I making a sound desicion here?
#6
JK Newbie
Join Date: Dec 2009
Location: San Francisco, CA
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://www.jk-forum.com/forums/images/icons/icon1.gif)
i have 35's with 5:13. before the new tires and gearing (3.73 prior), i would be at about 2,000 rpm at 72 mph. now i'm at about 2,500 at 72 mph (actual speed, not what the speedometer says). when i maintain ~75 mph, i am around 16.5 mpg. i calculated it with my 2 last tanks of gas (70 mile highway commute, with pockets of traffic). before, i think i was around 20 mpg.
you may want to consider 4.88. this should get you (slightly) better mileage than the 5:13 and still give you some power to get your jeep moving. once you throw on the 35's, you have to accept that you will lower your mpg.
also, i would stay away from max traction tires if you are looking for better mileage. my car tends to roll to a stop much sooner with the mud terrains.
you may want to consider 4.88. this should get you (slightly) better mileage than the 5:13 and still give you some power to get your jeep moving. once you throw on the 35's, you have to accept that you will lower your mpg.
also, i would stay away from max traction tires if you are looking for better mileage. my car tends to roll to a stop much sooner with the mud terrains.
#7
JK Junkie
![Default](https://www.jk-forum.com/forums/images/icons/icon1.gif)
Thanks for the quick suggestions. The more I read the more it is looking like 4.56 would give me the best mix of power and MPG. I live in flat Gulf Coast Tx and really only use the 4WD for some mud and sand getting to fishing holes...I do about 30 mile round trip at 70/75 MPH for work everyday. Am I making a sound desicion here?
Trending Topics
#8
JK Junkie
Join Date: Jul 2008
Location: Lakewood, OH
Posts: 3,017
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://www.jk-forum.com/forums/images/icons/icon1.gif)
With 3.21's, there is no chance of a flashpaq coming close to the performance gain of re-gearing. Will it help? Of course. But nowhere close to gears.
As you've already seen, that chart takes a lot of the 'opinion' out of the decision and puts it into perspective with numbers you can understand and feel...
As you've already seen, that chart takes a lot of the 'opinion' out of the decision and puts it into perspective with numbers you can understand and feel...