Originally Posted by
ehdeeboi
I tried and failed miserably using the calculator on the Sheldon Brown site and I am not good at math either. What would be the difference (percentage-wise) between 11-25 to 11-28
You have a few fixed numbers:
Smallest chainring: 34 teeth
Wheel circumference: 2155mm (rough estimate for a 700x25 tire)
Desired cadence: 90 (easy enough to edit)
Cassette cog teeth: 25 or 28
With those numbers and some unit conversion, you can figure out how fast you'll be traveling:
34 / 25 * 2155 / 25.4 / 12 / 5280 * 60 * 90 = 9.83mph
or
34 / 28 * 2155 / 25.4 / 12 / 5280 * 60 * 90 = 8.78mph
Change numbers out to suit your reality.