How about you assist me and the OP in using the Sheldon Brown Gear Inches calculator, instead of treating me like a student in your high school math class. I just punched in the chainring number in the chainring spot, the cog in the custom sprocket space and set the wheel size to 700 X 25 (25-622). Then hit calculate. Now what did I do wrong? No, I dont fully understand the way the GI are calculated, so it doesn't jump out at me that the math for a lower gearing didn't add up. I appreciate you setting the OP straight and not letting me share bad info, but your tact leaves a bit to be desired. Thanks again.