The stock size KO2s (265/70/17 C) are 31.7" tall, 10.7" wide.
The 255/75/17 Cs are 32.1" tall, 10" wide.
So very close, but the 255s are slightly taller and skinnier.
Lots of guys run the 275/70/17 E, which are 32.2" tall, 11" wide. They also weigh 55lbs vs the 255s weighing 45lbs.
The...