265 & 285 is the section width of the tire in millimeters... 10.6" vs. 11.4"... The second # in the equation is the aspect ratio (percentage of section width, represented in sidewall height). Your stock size was 265/70r16, so that's 10.4" wide by 30.6" tall. Conversely, 265/75r16 is 10.4" wide by 31.6" tall & 285/75r16 is 11.4" wide by 32.8" tall.

Fwiw, I run 265/75r16's on my wife's '01 4Runner, stock wheels, no wheel or coil spacers, no rubbing - even at full stuff. <img src="/forums/images/graemlins/cheers.gif" alt="" />

4xGeek (Chris)
'97 T-100 4wd sr5-suto, 3" BL, 1.5" BJ spacers, 35" ProComp AT's, 4.88's, Bilsteins x 6, etc...

No longer stuck in SoCal!! smile