I have read of a gearing arrangement (or perhaps it could be called a shifting ideal) called
"nine-in-a-line" from the days of 5 speed freewheels used with a triple crankset. As I understand it
the idea was to use the outer chainring just with the outer 3 freewheel cogs, the middle chainring
with the middle 3 cogs, and the inner chainring with the inner 3 cogs. It makes sense because then
the chainline would never be more than one position off perfectly straight.
Now however a mix of really wide clusters with 8, 9, 10 cogs (and more to come no doubt) combined
with short chainstays makes for chainlines with lots of deflection.
Does chainline matter less than those nine-in-a-line guy thought or have chains gotten better so
they can accept the greater defection (or bending or whatever term you want to use. Lets not get
into a semantic argument about the choice of one word when it's clear what is intended). Or is it
just that we've gotten so obcessed about judging the technical merit of a drivetrain by counting the
number of cogs that we simply ignore chainline?
From time to time I've also wondered what will happen when clusters grow to such a large number of
cogs that even one-tooth jumps result in a largest cog that exceeds the macho limit of say 23 teeth?
Will special cassettes have to be made with the last 3 or so cogs all 23 teeth to avoid the
extra-small-jockstrap stigma that might be a problem for some? But then what about the extra weight
of those surplus cogs (horrors)?
Bob Taylor