2015 JKU on 37" tires
03-22-2015, 05:59 PM
#1
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2015 JKU on 37" tires
Hey I am new to the jeep world. I currently have a 2015 jeep jk with a 2.5" lift. I plan to also do a small body lift to help make room for 37" tires. I have an auto trans. What would be the best gear ratio to use for the new tires? Any help is much appreciated.
03-22-2015, 06:20 PM
#2
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4.88s. And with flat fenders and proper bumpstop you should clear the 37s fine and won't need a BL.
Edit. Saw you had an auto
Edit. Saw you had an auto
Last edited by Stubicon; 03-22-2015 at 06:36 PM.
03-22-2015, 06:28 PM
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With the 3.6 and 37's, strongly recommend 4.56's unless you are at high altitude or spend a LOT of time crawling.
My '13 on 4.56 with 37's is outstanding here at sea level. On the other side of the coin the 2014 shop rig has 4.88's and 37's. Hit 6th gear at 45... and runs 2950 RPM at 70, definitely not optimum for a daily driver.
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My '13 on 4.56 with 37's is outstanding here at sea level. On the other side of the coin the 2014 shop rig has 4.88's and 37's. Hit 6th gear at 45... and runs 2950 RPM at 70, definitely not optimum for a daily driver.
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03-22-2015, 06:33 PM
#5
JK Junkie
Are there programmers out for the 2015s? Chrysler locked up the computer again. I know RIPP is including a pre-2015 ECU with their kits for the 2015s. Ridiculous....
4.56 or 4.88. I had 4.88 and it was a bit much for the highway, but nice offroad.
4.56 or 4.88. I had 4.88 and it was a bit much for the highway, but nice offroad.
03-23-2015, 06:12 AM
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Diablosport is sending a PCU replacement and a tuner for $999 right now
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03-23-2015, 06:48 AM
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03-24-2015, 11:00 PM
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With the 3.6 and 37's, strongly recommend 4.56's unless you are at high altitude or spend a LOT of time crawling. My '13 on 4.56 with 37's is outstanding here at sea level. On the other side of the coin the 2014 shop rig has 4.88's and 37's. Hit 6th gear at 45... and runs 2950 RPM at 70, definitely not optimum for a daily driver. fontName: com.apple.kUIFontMagicSystemFontName, traits: 0, pointSize: 12.00, textStyle: (null), contentSizeCategory: (null)
03-25-2015, 03:27 AM
#10
JK Junkie
One concern is driveshaft speed. They're not designed to run at constant RPM's above a certain level (many max at around 3000 rpm). At 70, I'd expect your driveshaft to easily be above 3000 rpm. Divide your rpm at 70 by your final drive ratio and that will tell you the speed of your driveshaft.