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black71gp 04-09-2008 05:42 PM

new tire size? Change the speedo gear?
I am hoping to change from my stupid stock 215 tires to some 31x10.5's I found a good deal on some used wheels and tires to get me by. My question is I think i have the 3.07 gearing.. 97 stock with the 4.0 manual. so what new gear would i need to get to make the speedo right? does anyone have a list of what gears you can get for what tires/gears you have in your jeep???


AzTJ 04-09-2008 06:00 PM

There isn't a gear available for a 31" tire and 3.07 gears... it's not that big enough of a change to worry about it. You may be 2-3mph off and that's it.

black71gp 04-09-2008 06:02 PM

well that sucks...

Jma20a 04-09-2008 06:03 PM

when i put on my 31's the speedo was 10-15 off. when i am going 75 it says that i am going 60. all i do is go by the rpm's

AzTJ 04-09-2008 06:31 PM

No way - even with my 32's, I'm only 6 off.

debruins 04-09-2008 06:42 PM

it is (new tire size)/(old tire size) times (speed on speedometer)= actual speed
so if 31/30 X 60= 62 so barely a difference
i have 35's and im only off by 15% and i dont care, i like it i go the speed limit on my speedometer and thats usually just the speed they will never pull you over for, but still "speeding"

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