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-   -   Gears Gears and more Gears (http://www.wranglerforum.com/f210/gears-gears-and-more-gears-244155.html)

Usnrubi143 05-21-2013 02:52 PM

Gears Gears and more Gears
 
I am undecided between 4.88s or 4.56s, i have an 04 rubicon 5pd on a 3.5 longarm with 35s, i no i could keep the 4.10s and be "fine" but f that i am looking to find how the two do on the highway and offroad .I know the 488s are aweome offroad and so are the 4.56s ... like what kinda of rpms are you running at 70 -75 ... and mpg :deadhorse: ??? i no its gunna be bad i am just wondering how bad??

jeepwayoflife 05-21-2013 02:55 PM

To restore it to factory gearing, you would want to go 4.88. You should expect to gain a couple MPG back if you are used to 35's on 4.10. With 4.88 you would be going around 2,700 rpm at 75, assuming you have the NV3550 transmission

Use the transmission rpm calculator in the middle to check rpm at different speeds. The transmission ratios for the NV3550 are 4.01-2.33-1.39-1.00-0.78
Other transmission gear ratios can be found with a Google search if you need.

Big Cole 05-21-2013 03:31 PM

A stock rubi came with 31s and 4.10 gears which is close to 35s and 4.88s. Your rpms will be nearly identical as what was specified by the engineers. 4.88s and 4.56s aren't awesome offroad but merely as good as stock considering your larger tires

PHILDABEAST 05-21-2013 03:36 PM

I don't know how to post a link but look up the grimjeeper calculator and you can compare different gear ratios and tire sizes for your exact setup. It's a very handy tool.

jeepwayoflife 05-21-2013 03:42 PM

Quote:

Originally Posted by jeepwayoflife (Post 3778737)
To restore it to factory gearing, you would want to go 4.88. You should expect to gain a couple MPG back if you are used to 35's on 4.10. With 4.88 you would be going around 2,700 rpm at 75, assuming you have the NV3550 transmission

Use the transmission rpm calculator in the middle to check rpm at different speeds. The transmission ratios for the NV3550 are 4.01-2.33-1.39-1.00-0.78
Other transmission gear ratios can be found with a Google search if you need.

Oops, I told you about it but didn't give you a link! http://www.ringpinion.com/calculators/calc_rpm.aspx

PHILDABEAST 05-21-2013 03:44 PM

http://www.grimmjeeper.com/gears.html


Figured it out. I think

flflash 05-21-2013 03:51 PM

I'd go 4.88's with 35's I installed 4.10's with 33's ( had 3.70 originaly ) and now wish I would have installed 4.56"s.


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