Planning on regearing? You may want to read
06-13-2012, 08:12 PM
#151
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Originally Posted by Pablo97
<img src="https://www.jk-forum.com/forums/attachment.php?attachmentid=328864"/>
I have a similar issue. Every one I talk to at shops say go with 4.88 but everything im researching says go 4.56. I am probably go with 4.56 on my 2012 2dr sport Auto with 35 Toyos. Seems like the logical choice for SoCal. Lots of highway driving everywhere.
06-18-2012, 06:07 PM
#152
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For 2012, I think 4.10's that come with the Rubicon are a little too low, which encourages people to go to bigger tires! Over 2,500 rpm at 70 mph with stock tires? It's not needed. 5th gear in low range tops out at 40 mph with stock gearing and tires. With 4.10 and 35" tires, the gearing is perfect. After 7,000 miles like that, I went to 38.5x15 boggers and ran them around for a month at 9 psi on and offroad with the 4.10 gears before I finally pulled the trigger to regear. The new engine/tranny combo handles the higher gearing with relative ease. First gear in the new 5 speed auto is much lower than the old 4 speed and makes ideal gear ratios a lot different than the 2007-2011 jk's. I would only recommend 4.56's with 35" tires if you live at high elevation or plan to tow requently. I live in SoCal at 600 feet elevation, but the roads get to 7,000 feet within 50 miles of home if I go north (Alta Sierra) and it gets to 8,800 feet of elevation if I go south (Mt. Pinos). I still prefer 4.10's with 35's. Now that I went to 38.5x15.00, I have regeared to 5.13's, which is similar to the gearing of the stock Rubicon. It still seems a little bit too low geared, but with 130 lb tire/wheel combo and 15" wide bias ply paddle boats rolling down the road, the extra power is now welcomed.
06-18-2012, 06:53 PM
#153
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Originally Posted by Phimosis
For 2012, I think 4.10's that come with the Rubicon are a little too low, which encourages people to go to bigger tires! Over 2,500 rpm at 70 mph with stock tires? It's not needed. 5th gear in low range tops out at 40 mph with stock gearing and tires. With 4.10 and 35" tires, the gearing is perfect. After 7,000 miles like that, I went to 38.5x15 boggers and ran them around for a month at 9 psi on and offroad with the 4.10 gears before I finally pulled the trigger to regear. The new engine/tranny combo handles the higher gearing with relative ease. First gear in the new 5 speed auto is much lower than the old 4 speed and makes ideal gear ratios a lot different than the 2007-2011 jk's. I would only recommend 4.56's with 35" tires if you live at high elevation or plan to tow requently. I live in SoCal at 600 feet elevation, but the roads get to 7,000 feet within 50 miles of home if I go north (Alta Sierra) and it gets to 8,800 feet of elevation if I go south (Mt. Pinos). I still prefer 4.10's with 35's. Now that I went to 38.5x15.00, I have regeared to 5.13's, which is similar to the gearing of the stock Rubicon. It still seems a little bit too low geared, but with 130 lb tire/wheel combo and 15" wide bias ply paddle boats rolling down the road, the extra power is now welcomed.
06-18-2012, 07:12 PM
#154
JK Junkie
06-18-2012, 07:29 PM
#155
JK Junkie
06-18-2012, 08:22 PM
#156
JK Junkie
Depends what gears you have now. If you have 3.73's its not worth the money to change. If you have 3.21's, then its worth it. I have not driven a 2012 with 35's and 4.10's, but with the extra power the 3.6L has, it may be fine.
06-19-2012, 06:17 PM
#157
JK Junkie
06-20-2012, 08:02 AM
#159
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Well I guess these guys at the shops still don't know about 2012 gearing so i'll listen to you guys. I have 3.73 right now. And it doesn't seem worth it to me to regear to 4.18. So I guess 4.56 should do fine and makes a bit more sense.
06-20-2012, 08:40 AM
#160
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It's 2008 6speed. Tire weight? Hmm, website says 68lbs. I know they are the BFG 315/75/R16 AT Tires, measure 34.5 or 34.6:. I also have a roof rack, metal front and rear mopar bumpers, rubi sliders with moded rails. Pretty heavy.