Hey, i know some dicks ganna say search the forum but i just want some input im not looking for answers:flipoff2:. My 97 TJ is an Auto(TF999) with 3.07 gears and im going to need tire befor winter, the problem is come spring im swaping axles and putting a RE 3.5" superflex kit, the axles have 3.73. im not sure if i should just put a 2"bb and a set of 33s(i wanna run 33s on the new axles) and just deal with the mpg OR should i just get a set of 31s(running 30-9.5 now) and come spring buy another set of tires/wheels. the one thing that im afraid of is that i do high way driving everyday and as is at 70mph im at about 2500rpm i dont wanna put a set of 33s and then be at 2500rpm at 60mph. just wondering what my fellow wheelers think?
PA-XJ2

the one thing that im afraid of is that i do high way driving everyday and as is at 70mph im at about 2500rpm i dont wanna put a set of 33s and then be at 2500rpm at 60mph. just wondering what my fellow wheelers think?
PA-XJ2

If you are going to a bigger tire and keeping the same gears, the engine rpm's will be slightly lower at a given speed in the same gear.

but engine load goes up driving fuel consumption back up.

have fun dropping way far out of the revs you want for the motor to be efficient...or, welcome to 3rd gear (1:1) on the interstate. no more OD for you.

http://www.4lo.com/calc/gearratio.htm

and an even better one

http://www.jeeptech.com/javaAps/gta.html

have fun


i tossed a set of 31's on my b2 with a 3" BL and im suffering for almost a year seeing 3rd gear up small hills and very rarely seeing my 5th gear in the fm146. highway is ok for me tho. acording to the second link i sent with my 3.73 gearing and my 5th gear being 0.82 gearing im pulling 75 at 2500RPM with a 31 inch tire.

Whatever you do your mileage is going to suffer a bit.

Best to buy a cheap commuter and build the Jeep the way you want it.

thanks guy and the TF999 has no overdrive hell id love to not be in 3rd on the interstate but when your trans only has 3 gears 3rd becomes your friend real quick! hahah. my TJ was my DD and i was building a XJ for trails but i cant afford it anymore, so my TJ now takes on both jobs!

PA-XJ2

Whatever you do your mileage is going to suffer a bit.

Best to buy a cheap commuter and build the Jeep the way you want it.

registering and insuring a daily driver would only break even in about a year.

For a while i ran 35's with a 4.0L, Tf-999, and a 3.07 ratio. (I didnt want to spend any money on the D30 or 35.) I would not reccomend it, it was constantly working hard, and spent a lot of time in 2nd gear to get down the highway at a legal speed. If there was any head wind what so ever, it wouldnt hit 3rd. It sipped a bunch of gas even before i did that, but it became a real thirsty bitch after.

If it were me, I'd go with nothing larger than 31's.

yeah after seeing what you guy said and talkin to a few others i think im just ganna bite the bullet and buy a set of 31s and when i put the new axles in ill go with 33-12.5 on a 15-10" wheel. thanks

and off topic im getting great gas mileage from this comb (4.0L, TF999, 3.07gear) and when i say great mileage i mean 21-23mpg!! i will miss that but fuck it!
PA-XJ2