255/75R15 tires have a diameter of 30.1", a section width of 10.0", and a wheel diameter of 15". The circumference is 94.4" and they have 671 revolutions per mile.
Generally they are approved to be mounted on 6.5-8.5" wide wheels for passenger tires and 6.5-8" for LT tires.
Specs may vary by manufacturer. learn more