Proof 2012 Rubicons on 35s need 456 gears
08-01-2012, 04:07 AM
#51
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Originally Posted by ezav8tr
Disregard. I just went to the Jeep website and tried to build a new 2012 and it would not let me select 3.73 gears with a manual transmission. Apparently the 3.73 gears option is only for an automatic. Correct me if I'm wrong.
08-01-2012, 05:01 AM
#52
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you may need to go to 4.56 to regain stock pep, but you don't need it to be drivable. I have 2012 auto 3.73 and at 70mph i am at 2100 rpm. I am getting only about 1mpg less than when i was stock. I am a little slower than when i was stock but i still get on the freeway without any trouble.
I am sure once you get your 35's you can see for yourself if regaining that loss in "pep" is wroth the gearing change. I would recommend getting the lift and wheels first then decided if the next few grand you spend should be gears or if you can live with the speed and spend that on something else.
I am sure once you get your 35's you can see for yourself if regaining that loss in "pep" is wroth the gearing change. I would recommend getting the lift and wheels first then decided if the next few grand you spend should be gears or if you can live with the speed and spend that on something else.
08-01-2012, 07:04 AM
#53
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The difference between 4.10's and 4.56's is so little if you did a side by side test with 35's you would have a hard time telling the difference. With my 2012 Rubi. Manuel with 4.10's and 35's, on the highway I travel 65 to 75 mph and get between 16 and 18 mpg. I have no issues with the power and it is fine off the line. It may be worth the money to go from 3.73's to 4.56's but not from 4.10's.
08-02-2012, 08:04 AM
#54
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The difference between 4.10's and 4.56's is so little if you did a side by side test with 35's you would have a hard time telling the difference. With my 2012 Rubi. Manuel with 4.10's and 35's, on the highway I travel 65 to 75 mph and get between 16 and 18 mpg. I have no issues with the power and it is fine off the line. It may be worth the money to go from 3.73's to 4.56's but not from 4.10's.
08-16-2012, 06:16 AM
#55
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After reading everyone's comments to my original post I realize the title of my thread "Proof 2012 Rubicons on 35's need 456 gears" is a bit strongly worded.
As one poster has mentioned the charts Ive posted only prove how a person should regear in order to regain a previous RPM range after they have gone to a bigger tire.
In the end you dont NEED to regear anything. There is no rule that suggests you have to do anything.
I will note the following though. The best way to gain more torgue is to regear. Torgue being more important than horsepower for off road vehicles and rock crawlers, moving to a larger tire will decrease torgue. For jeeps that are driven mostly on pavement, the loss of torgue may not mean much to you. For those however that are going to put their rigs in the mud bogs, trails, and rocks, you can always use the extra torgue. I would still suggest for those users, to regear when larger tires are put on.
As one poster has mentioned the charts Ive posted only prove how a person should regear in order to regain a previous RPM range after they have gone to a bigger tire.
In the end you dont NEED to regear anything. There is no rule that suggests you have to do anything.
I will note the following though. The best way to gain more torgue is to regear. Torgue being more important than horsepower for off road vehicles and rock crawlers, moving to a larger tire will decrease torgue. For jeeps that are driven mostly on pavement, the loss of torgue may not mean much to you. For those however that are going to put their rigs in the mud bogs, trails, and rocks, you can always use the extra torgue. I would still suggest for those users, to regear when larger tires are put on.
08-16-2012, 06:26 AM
#56
JK Freak
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Here is a site that explains the loss of Torgue
http://www.4x4abc.com/4WD101/math_wheels.html
Here are some good calculators
Calulators from www.4Lo.com
http://www.4x4abc.com/4WD101/math_wheels.html
Here are some good calculators
Calulators from www.4Lo.com
07-21-2013, 08:06 PM
#57
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I think I found the hard evidence I've been looking for regarding regearing my 2012 Rubicon on 35's. My friend turned me onto this site which compares Max Speed for each tranny gear given tire size and axel gear.
The first chart below compares gear max speeds between 3.73 and 4.10 gears on 32 inch tires. You can see how the 4:10 shorten the max speed of each gear.
Attachment 341623
The second chart shows what happens to the max gear speeds when you move up to 35 in tires on 4:10 gears. You will notice by upping the tire size you are actually very close to the Rubicon on 32 inch tires using 3.73's.
Attachment 341622
The third Chart shows 35 inch tires using 4.56 gears compared to 4.10s using the stock 32 in Rubicon tires. As you can see by going with the 4.56s on 35s that you actually come extremely close to replicating the same speeds as a 32in wheel using 4.10s.
Attachment 341624
If you have a 2012 Rubicon and you want to regain the stock pep after you put 35 in tires on your jeep, you can get this be regearing to 4:56.
This is what I needed to see and now I know that regearing is in the future for me.
The first chart below compares gear max speeds between 3.73 and 4.10 gears on 32 inch tires. You can see how the 4:10 shorten the max speed of each gear.
Attachment 341623
The second chart shows what happens to the max gear speeds when you move up to 35 in tires on 4:10 gears. You will notice by upping the tire size you are actually very close to the Rubicon on 32 inch tires using 3.73's.
Attachment 341622
The third Chart shows 35 inch tires using 4.56 gears compared to 4.10s using the stock 32 in Rubicon tires. As you can see by going with the 4.56s on 35s that you actually come extremely close to replicating the same speeds as a 32in wheel using 4.10s.
Attachment 341624
If you have a 2012 Rubicon and you want to regain the stock pep after you put 35 in tires on your jeep, you can get this be regearing to 4:56.
This is what I needed to see and now I know that regearing is in the future for me.
The gear ratios used are incorrect this was taken from another site :
The 2012 5speed Auto (A580) gear ratios are:
1st - 3.59
2nd - 2.19
3rd - 1.41
4th - 1.1
5th - 0.83
Redline (RPM) 6400
Last edited by RRP777; 07-21-2013 at 08:50 PM.
07-21-2013, 08:24 PM
#58
JK Freak
Thread Starter
Im going from memory here but I think the gear ratios you posted are extremely close to the ones I used. The redline wasnt part of the equation thats why I left it at 8400.
