2.5 RC lift. 34 trail grappler and Superchips. Not bad at all. 3.73 4 door

 

Play around with the chart in the FAQ's.


As an example:
Auto, 3.73's, 34" tires (assuming your new 35's will measure out at 34")
= 1781 rpm @ 70 mph
- which is way too low to hold freeway speeds, so you will constantly be dropping in and out of OD, which causes more wear and tear, heats up the tranny, and gives much worse mpg's.

The OD ratio is 0.69, so divide the OD On rpm by this to get your OD Off rpm.
1781 / .69 - again, assuming 3.73 and 34" actual height tires:
= 2581 rpm @ 70 mph OD Off
- which puts you right in the mid-2k range that this engine likes.


If/when you jump up to 5.13's, you would get:
= 2450 rpm @ 70 mph OD On
= 3550 rpm @ 70 mph OD Off

A benefit to proper gearing is that dropping down out of OD into 3rd (5.13's) is a much more manageable rpm than dropping from 3rd to 2nd (3.73).

 

so is running the stock 3.73's in my 6speed going to be bearable with 35"s?

 

Im running 35's with 3:73 and it was very underpowered at hwy speeds then installed a K&N cold air intake and a Hypertech max programmer and actually am very pleased. I am also getting 17 mpg average and about 19 hwy. I didn't buy the intake and chip for milage, just help with power untill regear, but damn I'm blown away with milage increase from 11 mpg avg. I will say I have it programed for premium butt hell thats only a little more per tank and it does help. All in All I will still regear butt will be glad to have made these mods first!!

 

i have 35 bfg km2 with stock 07 2dr wrangler x gears. (3.73 i think)

i am very very pleased with how it is responding. i barely notice any power loss.

 

35" km2s on a 2dr sahara with 3.73s auto. Definitely noticed a power loss but superchips 91 tune made it about as good as stock. My od is always off on highway cuz it will constantly shift back and forth. Gas milage on highway went from 19.5 to 16. Definitely needs to be regeared but is tolerable for a couple of months or so.

 

I have 37s with 3.73s and a 6 speed, around town its totally fine. i get about 15mpg (from the gauge that lies on the dash lol). off road....its only ok

 

I've been running my 35" MTR's for about 4 months now with 3.73 gears. Gas mileage sank like a rock immediately. My CAI and Superchips programmer makes driving tolerable....need to re-gear soon.