My only concern about the 6 cog limit was freewheel availability. Much
easier to locate freewheels with the right gears if you can choose
between 5,6, and 7. I understand the rule if it's simply to limit the
performance of the bike, like the 32 spoke min., even if 7 cogs and 28
and lower spoke counts were in use well before 1984.
Interesting event; makes me want to train for it,
Mitch Harris
Little Rock Canyon, Utah, USA