Frank Krygowski wrote:
Amit wrote:


okay, i don't understand the origianl need for log plots of gear
inches. i've seen how the spacing of gears on a single chainring
for a
typical bike is somewhat logarithmic.

perhaps you'd want the gears across the entire range to be lined up
on
the log plot as a magical ideal, but that seems pretty arbitrary.

i don't see how a log plot helps you elimintate duplicate gears in
a
way that you couldn't do on a linear plot, or even by simply
eyeballing the gear chart.

The key is that on a log plot, equal percent changes show up as equal

distances between points.

If you felt that each gear change should have the same effect (say,
reducing your gear ratio by 5%) then you could plot different cog
combinations until you achieved equal spacing on a log plot. If you
felt you wanted greater spacing in the low gears and finer spacing in

the high gears, you could verify that as well.

If you plotted things on a linear scale, or just looked at the number
of
gear inches, you might think shifting from a 100 inch gear to a 95
inch
gear would feel the same as shifting from a 30 inch to a 25 inch.
But
in practice, the former is a fine adjustment, the latter is a pretty
big
jump.

Of course, many people rode far, fast and long without giving this a
thought. It all depended on how much you were into the technology
and
the numbers.

--
--------------------+
Frank Krygowski [To reply, remove rodent and vegetable dot com,
replace with cc.ysu dot edu]

It's not as important today as 20+ more years ago, when 5 or 6 speeds
were all that were available. It's also not at all difficult to do if
log paper is used. What I was saying is that it's still a good way look
at ones gearing. So far spread sheets baffle me. They sure don't look
like any math I've ever done. Also my peculiar mind has to see or
imagine seeing something in order to understand it. Words just float
around in empty space.
Happy Holidays, John