What gears ratio for a 2012 on 37's?
03-23-2012, 03:53 PM
#31
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2012 JKUR Auto with 4.10's here. Stock 32 BFG's are turning 2900 at 70. I feel 35s will bring the RPMs down into the engine's power band a little better. The Jeep is just a rocket when it down shifts at 65 or 70 because its so wound up already. The new engine is so much more powerful than my 2008 Wrangler with the 3.8L it is not funny. I drive big dumb diesel pick-ups at work so when I get to drive my Jeep it feels almost.....fast. I think most JKUR owners are going to be able to live with 4.10s and 35s for all around use. I just ordered a Metal Cloak 3.5 Game Changer lift and 35 inch MTRs. I guess we will see.
03-26-2012, 09:03 AM
#32
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Here is how 5.13's and 37's are working for me:
This is my setup: 2012 manual tranny, 37 BFG km2's, 5.13 gears. I have made the necessary changes w the procal. The factory specs on the km2 measure 36.8. A little smaller than 37.
Here are the highway RPM numbers:
60mph = 2300 rpm
65mph = 2500 rpm
70mph = 2700 rpm
75mph = 2900 rpm
MPG showing 16 mpg at 65 mph, 14mpg @ 70mph, 12mpg at 75mph (on the vehicle info readout). I'm happy with that since I don't give a rat's #@# about mileage. If I did I wouldn't be rolling on 37 inch tires.
Sounds like most are going to go with 4.88's for 37's with the new manual 3.6. I think the 5.13's work well though. Especially for wheeling, steep highway roads, or towing.
Chime in here if I'm missing something.
This is my setup: 2012 manual tranny, 37 BFG km2's, 5.13 gears. I have made the necessary changes w the procal. The factory specs on the km2 measure 36.8. A little smaller than 37.
Here are the highway RPM numbers:
60mph = 2300 rpm
65mph = 2500 rpm
70mph = 2700 rpm
75mph = 2900 rpm
MPG showing 16 mpg at 65 mph, 14mpg @ 70mph, 12mpg at 75mph (on the vehicle info readout). I'm happy with that since I don't give a rat's #@# about mileage. If I did I wouldn't be rolling on 37 inch tires.
Sounds like most are going to go with 4.88's for 37's with the new manual 3.6. I think the 5.13's work well though. Especially for wheeling, steep highway roads, or towing.
Chime in here if I'm missing something.
10-03-2012, 11:50 AM
#33
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JayRud, I have 2012 6sp JKUR with 37 Km2's and im going to regear in the next few weeks so my question for you is, are you still happy with your 5.13's or would you have gone with 4.88?? Your opinion and any other one who would like to chime in would help me out thanks.
10-03-2012, 12:13 PM
#35
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I can not speak for 37's but i can tell you that my 35's on my 12 rubicon with 5 speed auto and 373's is a perfect match on and off road for me.
Last edited by bearman95; 10-03-2012 at 12:22 PM.
10-03-2012, 12:52 PM
#36
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I am runnning a 37 on a 12 rubi as well adn did alot of research and what i found out is that 456 are the way to go. I personally didnt do them and am driving around with stock programming and it feels fine. When i reprogrammed with procall for tire size then it felt like shttt. Currently running stock program
10-03-2012, 09:54 PM
#37
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JayRud, I have 2012 6sp JKUR with 37 Km2's and im going to regear in the next few weeks so my question for you is, are you still happy with your 5.13's or would you have gone with 4.88?? Your opinion and any other one who would like to chime in would help me out thanks.
Last edited by JayRud; 10-03-2012 at 09:57 PM.