Originally Posted by San Rensho
To calculate gear inches, you divide the number of teeth on the chainring, by the number of teeth on the cog and multiply by 27 inches. Most people think, "Oh, I'm going from a 25 tooth cog all the way to a 29 tooth cog, so there must be a huge difference in gearing." Well, if you do the math, its about 6 gear inches difference which is not that much. Its less of a jump in gearing (do the math) than from a 52/13 to a 52/14.
If you can feel 2 gear inches, you are a better man than I.
What he vvv said.
Originally Posted by HillRider
No, not really. What you "feel" on gear changes is the % reduction or increase, not the pure number.
Sort of like price changes. If a new car increases from $20,000 to $20,005 it's not the same impact as if a can of coffee increases from $10 to $15. Same $5 change but not perceived the same.
My friends on the track are uber sensitive about gear ratios...gear inches was explained to me like this:
If my bike has a 6 gear inch difference compared to your bike, then our bikes will be 6 inches apart every revolution fo the crank. Consider track cyclists spinning at 150-180 rpms, races are won and lost by a gear inch or less...from what I understand.