Anyone ever try Gain Ratios
 

I was reading Sheldon Brown's article on Gain Ratios. Very interesting idea, anyone ever use it to make a crank or cassette decision? http://www.sheldonbrown.com/gain.html

Tim

I calculate speed at 75 and 100rpm when I look at ratios.

speed at rpm seems the most useful. Gear inches also work for me, just because I'm old enough to relate to when it was the accepted measure, and I know what a 38 gear inch feels like compared to a 45 gear inch. But without some experience and experimentation, Gear Inches only tell you how big a bigwheel bike you'd have to ride to get the same result.

:roflmao: True, but funny. :roflmao:

In reality, all those measures do the exact same thing for you. Personally, speed at RPM (and in particular 60 RPM and 90 RPM) is what interests me the most. But when making gearing decisions, since all I'm considering is choice of chainrings and cogs, I find the easiest calculation to make (one that's even readily estimated mentally) is simply the ratio of chainring teeth to cog teeth. For example, 52/16 = 39/12 since they're both equivalent to 13/4. (Not a very useful example, but with nice round numbers.) I just decide what range of ratios I really need (based on prior calculations of speed at RPM) and gear accordingly.