Originally Posted by
prathmann
Except that it wasn't when the experiment was actually done.
Note that similar controlled experiments are done all the time with proposed new medicines whose inventors have good theoretical grounds for believing they will be effective. Some of them actually do work and are adopted while others are disappointing and are rejected.
problem here is that the two parts of the chain are not subjected to the
same conditions independently. the gunk on the dirty chain will spread to
the cassette and to the clean chain. not knowing the specifics of the lube
used, could be allowing more and bigger grit particles onto the bearing
surfaces of the clean chain while the dirty chains "pores" are blocked. so
the grit carried by the dirty chain is constantly being fed into the clean one.
plus there is the combined effect of (at least) three grinding processes that
may work at different rates, with no understanding of the relationship: dirty
chain bearing surfaces, clean chain bearing surfaces, cassette cogs....
i'd be more inclined to take it seriously if two identical drivetrains were put
together in a sealed environmental enclosure and subjected to identical
conditions, with one cleaned at specific intervals, as a starting point.