SM> Can someone please explain just what a "gear inch" is and how to 
 SM> measure it?  I know it has something to do with how far the tire 
 SM> moves for a given pedal input but I'm not clear on the details.
It is a reminder of the old "penny farthing" high-wheelers. You calculate 
the gearing as if you are running a large wheel of that diameter. Assuming 
you have a wheel diameter of 27 inches, you calculate gear inches by 
counting teeth in the chain ring and the rear cog, dividing and then 
multiplying by 27". In other words, you are running a 42T front and a 21T 
rear, a ratio of 2.0. Multiply that by 27 and you have a "wheel" of 54".
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 * Freddie 1.2.5 * When I was a kid we had to chisel taglines on the cave 
wall.
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