I was answering a post in another thread. Thought this might be helpful for folks wondering about gear ratio`s and tire sizes.
Take a look at these and plug your numbers in.
4Lo.com :: Final Gear Ratio, Crawl Ratio, Tire Size Calculators
Gear Ratio Calculator I like this one FWIW!!
Using these charts you can crunch numbers and find the optimum set up for your needs.