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thank you so much CTony for sharing this fascinating find!
the Riva-Sport marque is one with a long and well documented history -
it is derived of Cycles Alphonse Thomann of Puteaux France which launched in 1900.
here is a head emblem from an Alphonse Thomann machine which exhibits a strong resemblance to that of your bicycle -
a Thomann head emblem from back when the firm was located in its place of origin, Puteaux -
post card image of a Thomann sponsored racer ca. 1919 -
coming up to a slightly later era -
in 1949 the Thomann and Riva Sport marques became the property of an entity termed SCCM which stands for Societe des Constructions Mecaniques. this firm based in Vichy, France. production in that year was approximately 3000 machines.
your example appears to date from this post-1949 era.
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on to your cycle -
frame -
head lugs are NERVEX feature cut pattern nr. 86bis
their nozzle cut is not shown well enough in images provided to make an identification
from what can be seen in photos fork crown appears it may be NERVEX pattern Nr. 2
seat lug and bottom bracket shell models cannot be identified from photos provided
markings on bottom bracket shell -
there appear to be at least three of these
the set immediately below the NERVEX name indicates technical information such as the angles and diameters of the shell's socket openings and is not a serial nor a model number
the largest font set of markings were put in post-manufacture and may have been done by a licnesing agency
there is a third set of smaller markings between the two which may be an actual serial from the manufacturer
pump pegs are NERVEX item Nr. 848
frame tubing and threading will be of metric dimension:
top tube 26.0mm diameter
down and seat tubes 28.0mm diameter
steerer 25.0mm diameter
bottom bracket threading 35.0mm X 1.0
steerer threading 25.0mm X 1.0
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fittings -
the brake pads in both calipers are set at/near the top of the adjustment slot
this indicates a mis-match between the calipers and the wheel diameter
bicycle manufacturers typically select a caliper reach for a model of bicycle so that pads will be at/near the centre of the adjustment slot
calipers in this case appear they
may be CLB brand
possible wheels may not be original to bicycle; check
rims for manufacturer marking, if manufacturer french they are probably original, if manufacturer british they are probably replacements
if wheels replacements it is likely that originals were size 650B
the 96mm dimension you found for the front fork/hub is standard for France at this time
keep in mind the possibility that the cycle
may have originally had a derialleur geared drive train of 1/8" 3V or 4V
since the stem is a clear replacement it is possible that the bar and brake levers may also be replacements...
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readers should be able to give addition information on the cycle with the posting of further imagery
if you ask her to stand for a second photo session please direct her to pose in full sunlight
thanks again
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