Here are some specs for you.

265/70-16
Diameter inches (mm) 30.61 (777.4)
Width inches (mm) 10.43 (265)
Circum. inches (mm) 96.15 (2442.27)
Sidewall Height inches (mm) 7.3 (185.5)
Revolutions per mile (km) 658.95 (409.45)

265/75-16
31.65 (803.9)
10.43 (265)
99.43 (2525.53)
7.82 (198.75)
637.23 (395.96)

Note that all tire manufacturers sizes vary slightly.

http://www.tacomaworld.com/forum/tir...0r16-265-75r16