Best gear ratio for Daily Driver
05-27-2009 | 06:42 AM
#22
JK Freak
Joined: Aug 2007
Posts: 505
Likes: 0
From: Rancho Cucamonga, Ca
If you're towing, you gotta go 4.88s. I'd say 5.13s but you have a D30. You are going to be surprised at not being that surprised. What does that mean?
I lived with 35s and 4.10s for over a year and hated every minute of it. I was looking forward to the 5.13 days like the second coming and when it happened I was underwhelmed. I thought 5.13s weren't drastic at all, in fact I don't think I am quite back to stock with all the extra weight that I've added in bumpers, wheels and tires. With my well worn 34.5 (315s), I'm runnin about 2500 +/1 100 rpm @ 70-72 mph, my freeeway cruise speed and i think that's just about the sweet spot of the rpm range for cruise.
I lived with 35s and 4.10s for over a year and hated every minute of it. I was looking forward to the 5.13 days like the second coming and when it happened I was underwhelmed. I thought 5.13s weren't drastic at all, in fact I don't think I am quite back to stock with all the extra weight that I've added in bumpers, wheels and tires. With my well worn 34.5 (315s), I'm runnin about 2500 +/1 100 rpm @ 70-72 mph, my freeeway cruise speed and i think that's just about the sweet spot of the rpm range for cruise.
05-27-2009 | 06:49 AM
#23
JK Freak
Joined: Jan 2008
Posts: 622
Likes: 1
From: Waterford, MI
If you're towing, you gotta go 4.88s. I'd say 5.13s but you have a D30. You are going to be surprised at not being that surprised. What does that mean?
I lived with 35s and 4.10s for over a year and hated every minute of it. I was looking forward to the 5.13 days like the second coming and when it happened I was underwhelmed. I thought 5.13s weren't drastic at all, in fact I don't think I am quite back to stock with all the extra weight that I've added in bumpers, wheels and tires. With my well worn 34.5 (315s), I'm runnin about 2500 +/1 100 rpm @ 70-72 mph, my freeeway cruise speed and i think that's just about the sweet spot of the rpm range for cruise.
I lived with 35s and 4.10s for over a year and hated every minute of it. I was looking forward to the 5.13 days like the second coming and when it happened I was underwhelmed. I thought 5.13s weren't drastic at all, in fact I don't think I am quite back to stock with all the extra weight that I've added in bumpers, wheels and tires. With my well worn 34.5 (315s), I'm runnin about 2500 +/1 100 rpm @ 70-72 mph, my freeeway cruise speed and i think that's just about the sweet spot of the rpm range for cruise.
It's an apple to oranges comparison and a huge pet peeve of mine when auto guys suggest really short gearing to the 6 speed guys based on their experience which is totally irrelavant. I saw one thread recently where an auto guy suggested a 6 speed guy run 5.13s with 32" tires.
Last edited by Doc_D; 05-27-2009 at 06:57 AM.
05-27-2009 | 10:59 AM
#24
JK Freak
Joined: Aug 2007
Posts: 505
Likes: 0
From: Rancho Cucamonga, Ca
He has a 6 speed you have an auto. His 6th gear is .84:1 while your 4th gear is .69:1. His 1st gear is 4.46:1 compares to your 1st gear of 2.84:1.
It's an apple to oranges comparison and a huge pet peeve of mine when auto guys suggest really short gearing to the 6 speed guys based on their experience which is totally irrelavant. I saw one thread recently where an auto guy suggested a 6 speed guy run 5.13s with 32" tires.
It's an apple to oranges comparison and a huge pet peeve of mine when auto guys suggest really short gearing to the 6 speed guys based on their experience which is totally irrelavant. I saw one thread recently where an auto guy suggested a 6 speed guy run 5.13s with 32" tires.
He's intending to tow with 35s . . . are you serious?
05-27-2009 | 11:44 AM
#25
JK Freak
Joined: Jan 2008
Posts: 622
Likes: 1
From: Waterford, MI
You're correct. In a later post the original poster mentioned his 33s. I didn't read very well and was thought we were talking about 33s. I didn't realize he now has 35s. Sorry I'm just touchy on the subject because I've seen a number of people giving out some crazy advice to people with manuals based on their experience with their automatics (i.e. run 5.13s with 32s).
05-28-2009 | 08:13 AM
#26
Thread Starter
JK Newbie
Joined: Mar 2009
Posts: 8
Likes: 0
From: Westphalia, TX
"He has a 6 speed you have an auto. His 6th gear is .84:1 while your 4th gear is .69:1. His 1st gear is 4.46:1 compares to your 1st gear of 2.84:1.
It's an apple to oranges comparison and a huge pet peeve of mine when auto guys suggest really short gearing to the 6 speed guys based on their experience which is totally irrelavant. I saw one thread recently where an auto guy suggested a 6 speed guy run 5.13s with 32" tires"
So then Dr. D what would you recommend? I have a 2-door with dana 30 and dana 44 with 35" tires. My main concern is to be able to drive at highway speeds (70-75 mph) withOUT redlining . Thanks again to everyone's participation! Also, I have noticed that some people have issues with taller gears busting the skinnier pinions. Does that really become and issue on the highway? or when offroading. 
It's an apple to oranges comparison and a huge pet peeve of mine when auto guys suggest really short gearing to the 6 speed guys based on their experience which is totally irrelavant. I saw one thread recently where an auto guy suggested a 6 speed guy run 5.13s with 32" tires"
So then Dr. D what would you recommend?
I have a 2-door with dana 30 and dana 44 with 35" tires. My main concern is to be able to drive at highway speeds (70-75 mph) withOUT redlining . Thanks again to everyone's participation! Also, I have noticed that some people have issues with taller gears busting the skinnier pinions. Does that really become and issue on the highway? or when offroading.
05-28-2009 | 10:13 AM
#27
JK Freak
Joined: Jan 2008
Posts: 622
Likes: 1
From: Waterford, MI
I originally thought you were on 33s (one of your posts mentions having 33s but those must have been your old tires). So that's why I originally disagreed.
4.56s on 35s will put you at roughly 2,800 RPM at 75 MPH. This is almost exactly the same as 4.10s on a 32 inch tire. So if you ran your 4.10s on a 32 inch tire this will be about the same. If you ran 4.10s on a 33 inch tire, the 4.56s w/35s will be just a hair shorter than that combo.
4.88s on 35s will put your at roughly 3,000 RPM at 75 MPH.
5.13s on 35s will put you at roughly 3,150 RPM at 75 MPH.
5.38s on 35s will put you at roughly 3,300 RPM at 75 MPH.
I don't tow, I do about 50% of highway driving and the traffic around here moves at 80+ MPH. So for me I'm going to opt for the 4.56 when I swap my gears.
If the traffic around here was a little slower, if I drove on the highway less or I towed more I might consider 4.88s. But I'm not super comfortable driving for hours on end turning more than 3,000 RPM on pushrod 3.8.
4.56s on 35s will put you at roughly 2,800 RPM at 75 MPH. This is almost exactly the same as 4.10s on a 32 inch tire. So if you ran your 4.10s on a 32 inch tire this will be about the same. If you ran 4.10s on a 33 inch tire, the 4.56s w/35s will be just a hair shorter than that combo.
4.88s on 35s will put your at roughly 3,000 RPM at 75 MPH.
5.13s on 35s will put you at roughly 3,150 RPM at 75 MPH.
5.38s on 35s will put you at roughly 3,300 RPM at 75 MPH.
I don't tow, I do about 50% of highway driving and the traffic around here moves at 80+ MPH. So for me I'm going to opt for the 4.56 when I swap my gears.
If the traffic around here was a little slower, if I drove on the highway less or I towed more I might consider 4.88s. But I'm not super comfortable driving for hours on end turning more than 3,000 RPM on pushrod 3.8.
05-28-2009 | 10:37 AM
#28
JK Jedi Master
Joined: Jan 2008
Posts: 11,463
Likes: 162
From: Austin <--> Colorado Springs
The other point to think about is which gear do you tow in?
Don't know if it's actually an issue for you manual guys, but when I tow my 3500 lb boat with my auto, the OD is always off. This of course brings the revs up, so it's definitely a concern for my gearing choice. Anyway, if you tow in 6th, disregard...
Don't know if it's actually an issue for you manual guys, but when I tow my 3500 lb boat with my auto, the OD is always off. This of course brings the revs up, so it's definitely a concern for my gearing choice. Anyway, if you tow in 6th, disregard...
05-28-2009 | 03:00 PM
#29
JK Newbie
Joined: Jan 2009
Posts: 68
Likes: 0
From: KCK
I originally thought you were on 33s (one of your posts mentions having 33s but those must have been your old tires). So that's why I originally disagreed.
4.56s on 35s will put you at roughly 2,800 RPM at 75 MPH. This is almost exactly the same as 4.10s on a 32 inch tire. So if you ran your 4.10s on a 32 inch tire this will be about the same. If you ran 4.10s on a 33 inch tire, the 4.56s w/35s will be just a hair shorter than that combo.
4.88s on 35s will put your at roughly 3,000 RPM at 75 MPH.
5.13s on 35s will put you at roughly 3,150 RPM at 75 MPH.
5.38s on 35s will put you at roughly 3,300 RPM at 75 MPH.
I don't tow, I do about 50% of highway driving and the traffic around here moves at 80+ MPH. So for me I'm going to opt for the 4.56 when I swap my gears.
If the traffic around here was a little slower, if I drove on the highway less or I towed more I might consider 4.88s. But I'm not super comfortable driving for hours on end turning more than 3,000 RPM on pushrod 3.8.
4.56s on 35s will put you at roughly 2,800 RPM at 75 MPH. This is almost exactly the same as 4.10s on a 32 inch tire. So if you ran your 4.10s on a 32 inch tire this will be about the same. If you ran 4.10s on a 33 inch tire, the 4.56s w/35s will be just a hair shorter than that combo.
4.88s on 35s will put your at roughly 3,000 RPM at 75 MPH.
5.13s on 35s will put you at roughly 3,150 RPM at 75 MPH.
5.38s on 35s will put you at roughly 3,300 RPM at 75 MPH.
I don't tow, I do about 50% of highway driving and the traffic around here moves at 80+ MPH. So for me I'm going to opt for the 4.56 when I swap my gears.
If the traffic around here was a little slower, if I drove on the highway less or I towed more I might consider 4.88s. But I'm not super comfortable driving for hours on end turning more than 3,000 RPM on pushrod 3.8.
05-28-2009 | 04:28 PM
#30
Thread Starter
JK Newbie
Joined: Mar 2009
Posts: 8
Likes: 0
From: Westphalia, TX
4.56s on 35s will put you at roughly 2,800 RPM at 75 MPH. This is almost exactly the same as 4.10s on a 32 inch tire. So if you ran your 4.10s on a 32 inch tire this will be about the same. If you ran 4.10s on a 33 inch tire, the 4.56s w/35s will be just a hair shorter than that combo.
4.88s on 35s will put your at roughly 3,000 RPM at 75 MPH.
5.13s on 35s will put you at roughly 3,150 RPM at 75 MPH.
5.38s on 35s will put you at roughly 3,300 RPM at 75 MPH.
Now this is a pretty stupid question, but in order for me to get an accurate idea, how many rpm's would you say i'm turning with my 4.10's and 35's at 75 MPH? I have not recalibrated my speedometer and so I'm not positive as to what my guages are really telling me!