http://www.fordrangerforum.com/wheel...tire-size.html
All depends what size rim you have.
98-00
XLT 4x4, XLT Offroad, Trailhead(mild T-bar crank always recommended for leveling purposes, always remeber to get an alignment)(may want to also replace T-bars do to T-bar sag)
* 15x7 stock suspension - 30x9.5x15, 31x10.5x15, 32x11.5x15, 33x10.5x15(T-bar crank recommended), 33x12.5x15(will need trimming and T-Bar max)
* 15x8 stock suspension - 31x10.5x15, 32x11.5x15, 33x10.5x15(T-bar crank recommended), 33x12.5x15(will need trimming and T-Bar max)
* 15x8 & 15x10 body lift or suspension lift - 32x11.5x15, 33x10.5x15, 33x12.5x15, 35x12.5x15(trimming also involved in multiple areas and T-bar max...), 325x60x15(31x12.9x15)
* 15x8 & 15x10 body lift AND 4-5" suspension lift - 33x12.5x15, 35x12.5x15(T-bar crank recommended, were applicable), *Anything larger at your own risk or T-bar max and trimming*
* 16x7 stock suspension - 255x70x16, 265x70x16, 265x75x16, 285x75x16(mild T-bar crank recommended but might not be needed.)
* 16x8 stock suspension - 265x75x16, 285x75x16(same as above) 295x75x16(T-bar crank recommended and maybe trim.)
* 16x8 or 16x10 body lift or suspension lift - 265x75x16(16x8 only), 285x75x16, 305x75x16, 315x75x16(trimming also involved in multiple areas and T-bar max...)
* 16x8 or 16x10 body lift AND 4-5" suspension lift - 285x75x16, 305x75x16, 315x75x16(T-bar crank recommended, were applicable), *Anything larger at your own risk or T-bar max and trimming*
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