tire size help

Just got a 98 4x4 excab 4 cyl with 235 15's,I want to put 31's on it but not sure if truck will be able to handle them as it seems to be tall geared, any info will help. Thx Dan P.S will they kill my gas mileage or am i worrying about nothing?

 

31's on my truck made no difference but i have a v6, still get like over 20mpg

 

Look in your door jam for the gear code. It will be something like B03A

Compare to this chart.
First digit:

A = 7.5" ring gear
B = 8" ring gear
Next two digits:

01 = 3:42
02 = 3:58
03 = 4:10
04 = 4:56
05 = 3:15
06 = 3:91
07 = 4.30
Last digit:

A = 2 Pinion, Open
B = 4 Pinion, Open
C = 2 Pinion OEM Limited Slip
some '98-00 models have shown a BO code of "???" on the door plate; so far this turns out to be a 3.91 gear ratio, at least for the 5sp. RZN171L-CRPDKAB with factory 31s/265s should be 4.56 with the AT

If you have 4.10's then the tires will be absolutely fine, but if not you will notice a drop in power and MPG

 

thanks for the replys my code is B03A,which indicates 410's?if so truck is tall geared with m/t .still not sure about 31's 225/75r15 are the stock size 4 truck.

 

with 4.10's, you will pull the 31's just fine.