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Old 06-25-2014, 10:56 PM   #1
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Gear Question

Will 37s with 4:10s be as bad as 35s with 3:21s? Automatic Transmission.

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Old 06-26-2014, 09:39 AM   #2
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Anyone?

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Old 06-26-2014, 09:55 AM   #3
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http://www.4lo.com/4LoCalc.htm

It's worse, in that the ratio drops more.

32s to 35s with 3.21 gears gives an effective ratio of 2.9. A difference of .31

32s to 37s with 4.10 gears gives an effective ratio of 3.55. A difference of .55
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Old 06-26-2014, 10:25 AM   #4
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If that is the case I will definitely be sticking with 35s with my 4:10s
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Old 06-26-2014, 11:08 AM   #5
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If that is the case I will definitely be sticking with 35s with my 4:10s
The effective ratio is still higher than a jeep on 32s with the 3.21 gears but it's below a jeep on 32s with 3.73 gears.

It's nowhere near your original 4.10 ratio, though.

I'd say with the 35s as well.
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Old 06-26-2014, 11:52 AM   #6
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Looking at the gear chart it looks like 35s with 3.21s spins about 1800 rpms at 70 and 37s with 4.10s would spin about 2100 rpms.

Id go for it. You should be fine depending where you live and how you use your jeep.
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Old 06-26-2014, 02:18 PM   #7
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Go here: Gear Ratio Calculator

Not sure what year your Jeep is or what kind of transmission you have.

For 07-11, the automatic is the Dodge 42RLE and the manual is the NSG370 close ratio
For 12+, the automatic is the Dodge WA580 and the manual is the NSG370 close ratio (2012+ Wrangler)

Pick the one you have. The transfer case is the NVG241 (NVG241OR for a Rubicon).

Then put in the gear ratio and the tire size. You can see the side-by-side comparison of whatever gear and tire combination you want.

However, I'll tell you that 37's with 4.10's is close to 35's with 3.73's. Not ideal but you can live with it.
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Old 06-26-2014, 02:44 PM   #8
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Go here: Gear Ratio Calculator

Not sure what year your Jeep is or what kind of transmission you have.

For 07-11, the automatic is the Dodge 42RLE and the manual is the NSG370 close ratio
For 12+, the automatic is the Dodge WA580 and the manual is the NSG370 close ratio (2012+ Wrangler)

Pick the one you have. The transfer case is the NVG241 (NVG241OR for a Rubicon).

Then put in the gear ratio and the tire size. You can see the side-by-side comparison of whatever gear and tire combination you want.

However, I'll tell you that 37's with 4.10's is close to 35's with 3.73's. Not ideal but you can live with it.
Right now I have a 14JKU with auto tranny. Running 3.21s and was going to upgrade this summer.

Decided to trade it in and order a 15 JKU Rubicon HardRock. It will have 4.10s and an auto so I was just curious if it the 37s and 4.10s would be as bad as the 35s with 3.21s are.

Thanks for the info
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Old 06-26-2014, 03:01 PM   #9
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With 33s and a 2.5in lift, what is the proper gear ratio?
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Old 06-26-2014, 03:05 PM   #10
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Hey rookie question, Whats my gear ratio? I have a 2010 Jeep Wrangler. Thanks! I've been trying to figure it out and I have no idea.
Easiest way to check, assuming it has been changed after the factory is to check your build sheet.

Build Sheet:
http://m.chrysler.com/en/mobile/webs...ice/index.html

Go to Your Vehicle > Equipment Listing
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Old 06-26-2014, 03:08 PM   #11
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Gear ratio has a lot to do with preference and what you're using the vehicle for. Lift height isn't really a factor. Just tire size. Personally, I think that 3.73 gears with 33s is an adequate ratio.

Read this for more info on bigger tires and gears, Etc.

So you want bigger tires
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Old 06-26-2014, 03:11 PM   #12
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Gear ratio has a lot to do with preference and what you're using the vehicle for.

Lift height isn't really a factor. Just tire size.

Personally, I think that 3.73 gears with 33s is a good ratio.
Unfortunately I live close to New York City and do not have a lot of opportunities to go off-roading and such. I drive 50/50 city/highway.
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Old 06-26-2014, 03:25 PM   #13
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Unfortunately I live close to New York City and do not have a lot of opportunities to go off-roading and such. I drive 50/50 city/highway.
In that case 3.73 gears would be perfect. Allows for easy lower rpm cruising on the highway but also enough pep for stop and go traffic.
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Old 06-26-2014, 03:27 PM   #14
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In that case 3.73 gears would be perfect. Allows for easy lower rpm cruising on the highway but also enough pep for stop and go traffic.
Thanks! Does it have a negative affect on mpg?
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Old 06-26-2014, 03:34 PM   #15
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Thanks! Does it have a negative affect on mpg?
Well, it's a delicate balance.

Think of it this way.

If you have 32s and 3.21 gears with your combined driving, you may get .2 more miles per gallon than if you had the 3.73 gears.

BUT, if you had 3.73 gears and you go with 33s, you'll lose some mpg just because the tires are bigger and heavier (usually) and now your effective gear ratio is also a bit lower but not enough to make it sluggish. So that gear ratio is a "sweet" spot for enough performance and still be efficient.
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Old 06-26-2014, 03:58 PM   #16
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Article on gearing basics.

http://www.crawlpedia.com/thick_gears.htm
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Old 06-26-2014, 05:04 PM   #17
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Thank you! I found out I have 3.73! Thank you!
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Old 06-26-2014, 05:21 PM   #18
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Welcome

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