Try this rpm/mph calculator. In your case type in the mph, gear, and tire size then click the mph its pretty close. These calculators are a good tool when your thicking about gear changes.
What the tire says on the side (14x32) means almost nothing. It just gives you a ballpark figure.
To get a true tire size, take your roll out and divide it by 3.1416 and that will give you a exact tire height. Your 105 rollout, 105/3.1416=33.42
http://golenengineservice.com/calc/calcrpm.htm
http://www.1bad69.com/calc.htm