Quand le dérailleur
est de rigueur?
-- Brigitte Niquette
 lthough
it may be somewhat difficult to make out in the photograph on the left,
Brigitte's mountain bike is configured with conventional gearing as depicted
in the sketch on the right.
 
Look closely and you will see that the...
-
'Crankset' has three sprockets, each
one selectable by the 'front dérailleur'
and
the...
-
'Freewheel' has seven sprockets, each
one selectable by the 'rear dérailleur'.
Look closer still and you will be able
to count the 'teeth' on each sprocket...
-
Crankset: 28, 38, 48, and...
-
Freewheel: 13, 15, 18, 19, 21,
24, 34
It is customary to provide an 'index'
for each dérailleur
to denote the present position of the 'chain'...
-
Front dérailleur:
#1~28, #2~38, #3~48, and...
-
Rear dérailleur:
#1~34, #2~24, #3~21, #4~19, #5~18, #6~15, #7~13
The puzzle entitiled "Inches
per What?" provides the rationale for measuring the 'speed' of a bicycle
in 'inches' along with how to perform the requisite calculations.
|
How many 'speeds' are determined
by the dérailleurs on Brigitte's mountain bike?
|
|
