Oct 24 '06 - 373 W, 2 I - Vote Good + 3 :: Bad - 9 Nuts N' Bolts :: Pedals for French-threaded Bicycles
Published October 24th, 2006 by C.I.C.L.E.
Contributed by Harv
Old French bikes (Peugeot, Motobecane, Gitane) may have several
components with threads that are incompatible with modern parts. Say
you want to replace those clunky old pedals with a modern pair and
don't want to permanently alter the threads in the crank arms. Or maybe
you would, but don't have the expensive crank threading taps. This is
the problem I faced with my 1970 Motobecane folding bike.
Modern pedals have either the 9/16 English thread or the 1/2 inch,
which is common on BMX and older full-size bikes with one-piece cranks.
Neither of which will fit a French crank arm with 14 millimeter
threads. Replacement French thread pedals are hard to come by,
expensive and with limited selection. If you are lucky enough to still
have the original French pedals, then here is the work-around.
Select your choice of modern pedal, trying to get one with the length
of the spindle close to that of the original French one, or a bit
shorter if need be. Then 
disassemble the original pedals. This may
require destroying them if they are staked together and not bolted.
Discard all the pieces except the spindles, which are to
be reused.
Then dismantle the new pedals and re-build them around the French
spindles. You may need to shorten the old spindles 1/2 inch or so and
run enough 8 x 1.0 mm threads on the spindle to allow correct
adjustment of the bearings. The adjustable cups, balls, and locknuts
from the new pedals could then be used. Most pedals, old and new, have
the same cup adjuster threads on the spindle and use the same size ball
bearings. Save the spindles that were removed from the new pedals so
that they can be reinstalled if you decide to use the pedals elsewhere.
Your newly assembled modern pedals now have the original French
spindles with French 14 mm threads and bolt right up to the original
crank arms. Photo shows modern BMX pedals (with toe clips!)
installed into original French-threaded crank on my 1970 Motobecane
folding bike.
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