"to own one of a kind is nice, owning two or more is better."
the old wisdom became a pressing necessity, when a friend came over for a weekend, to sightsee the city on bikes.
i had to lend a bike from a friend, which for me was a rare exception: " Never depend on others, always own yourself"
after my guest had left, i decided to get me a second bike: not exclusively for guests, but my own daily needs as well. and moreover, it had to be used, stylish, and a story to tell !
this is one of the cellar storage rooms ...
... of "Der Drahtesel", my much preferred bicycle repair shop, because they well know my bike needs and philosophy.
unfortunately, no "ready-to-go" bike was for sale, so i asked permission to browse their hidden secret in their cellars.
15min before closing, i returned with this ugly-duckling:
its a folding bike branded "KARZENTRA" without saddle.
it features 20" rims, a collapsible steel frame,
a rear carrier, a handlebar, no gearshift, no bell, no light, no frills.
i wanted the bike, michael wanted 25 eur, the deal was handshaked okay.
a day later, reanimation started with adding an old saddle .
hours of screwing, fixing, replacing, drilling, greasing, adjusting, cleaning brought this ugly duckling lying dead under a pile of scrap in a dark, moist kiel cellar ...
... to a road safe, shiny, 70's style swan, waiting to hit the city roads again.
tail light with integrated reflector.
brass plate of a famous but discontued tech & bike store.
(not original, taken from another older bike, just too nice to be disregarded and left to the scrappers)
plastic saddle made in italy, plastic bag "westphal" made in germany.
rear frame dropouts, hub nuts, clamp bolts for carrier and mudgards. old original chain (lower part) in good condition had to be extended by 12 new links.
plastic tool container, not original, taken from another bike.
and not a clever idea either: due to its width, it interferes with the shoes heels when circling upward.
brand label on frame. "karzentra" was the bike brand of department store group "karstadt". this article mentions :
"Vor 75 Jahren, 1931, kaufte die Rudolf Karstadt AG das Kaufhaus Hansa am Seltersweg 28. 1932 wurde das Geschäft dann unter dem Namen "Karzentra" eröffnet, und 1949 wechselte der Name wieder."
front fork with generator "union", headlight "ruhla" / gdr.
the original brake was pressing onto the tire, but for safety concerns was replaced by this model made of chromed steel. it also allows fitting the headlamp on its pivoting bolt, but does not operate well on the slim steel rim side.
the frames are coupled by male/female flange plates,
which on the bottom lock by 2 male fingers protruding thru gaps in the rear frame. the lock nut with plastic grip on top is free from operation loads.
a rubber sleeve isolates the connectors to the rear light.
steering tube immersed to its lowest position.
labels heavily scratched, indicating intense (mis-) use
mudguards cleaned with steel wool, with the knife sharp tip ready to cut stupids animals (a protector is in planning ... )
permission was granted to proudly bear the sellers own label.
portside view. on floor, the red cushioned saddle cover thats pleasing the riders back - a typical accessory of the 70's and "must have" for "best aged bums". it was cleaned, received a new rubberband, and put away - as i certainly dont need it.
frame mounted lock by "hebie-trumpf" to block the spokes.
according the maker, these locks are long out of production.
time permitting, eventually a custom key will be filed. update: to gain theft security, the old circular spoke lock was moved from my full size bike to this one karzentra. for screws, 2 holes dia 3mm had to be drilled in the rear frame.
after folding bikes got popular in the late 60s, people soon learned that small wheels, a wobbly frame and no frills was exactly what "serious bikers" wanted. an exactly opposite trend then started with highly complicated, skinny handmade racers made by "hip & trendy" brands". Folding bikes became uncool and most ended in cellars or scrap. however, were practicality was wanted, they remained in service in ports, industrials plants, camping.
frame underside with stand "royal" / italy.
at the joint, the fingers protruding thru holes in the opposite flange are visible.
frame number stamped on crank housing.
crank bearing cleaned, greased, adjusted.
cranks fastened to crankshaft with wedges.
hub made by "renak" / gdr, now producing hub generators near itzehoe, schleswig-holstein, nothern germany.
renak continued the sachs products widely unchanged.
A brake lever from a sachs 3 speed gear hub was used because its connection to the frame was better than with the original straight renak arm.
welding marks on front rim, not ground to an even surface.
the uneven and low width of the chromed front rim make it unsuitable for using caliper brakes. retrofit is considered.
frame number : is it "delta 4726 & 91" or "delta 4726 891" ???
rear tire made by "pneumant" in former gdr
undersight: mudguard with cutout for original stamp brake,
headlight made by "ruhla" / gdr,
underside of saddle "royal" / italy.
saddle suspension by tension springs, not galvanized
crew of dutch schooner "thalassa" preparing for a party.
whatta beautifully shaped ... bike !
project "karzentra" klapprad / folding bike / faltrad:
start sep 19, finish sep 25, 2008 (preliminary, of course).
costs: bike 25 eur. saddle, badge, brake, tail light 10 eur.
shop costs (grease, electricity, tools, soap, beer): 20 eur.
total costs: 55 eur so far. the to-do list already shows: a 3x hub, saddle repair, shipping bag, some debugging and optimizing. See next images "building a bag".
modification after first trials: headlight moved to left fork leg, original brake fitted, toolbox on "pletscher"-plate removed . transport bag sewn from 3x coated nylon "m-bags", used by the us postal service to ship parcels by air.
bike collapsed to l=85cm, h=60cm, w=26cm. tools needed: pedals 15, handlebar 13, lines to keep parts together, carrying strap.
leather shoe around frame chainplate, protects bag against wear and puncture by sharp edges.
bike, free standing in bag.
two pockets for documents . adjustable nylon belt directly tied to bike, to avoid pressure on bike parts and loads on textile.
the top is a 30cm wide lash sewn to one side only, to follow the irregular contour and tolerate differing packing schemes.
Projekt " KARZENTRA " finished - again just for the moment : See next images "restaurating the saddle" .
saddle restoration - to keep the original shape of the bike:
due to a multiple cracked seat base of the italian "royal" saddle, an old saddle of german make "wittkopp" was acquired, with intact seat base and frame, but torn pvc cover.
it turned out, that also its steel frame was much stronger.
the seat base (l) is partly sheathed with new pe-foam.
to avoid cracks from 2-dimensional seat deformation, the most tortured areas where doubled, using patches of the old seat base.
the patches were welded by using an 100w soldering stick.
several springs from the old saddle were added - to meet the "well known" loads in operation mode "urban survivor" .
while the deformed original saddle made by italian "royal" had a rather weak frame and base plate, the refurbished saddle uses a stronger frame and thicker base plate of german saddle-maker "wittkopp".
the only remaining parts of the original "royal" saddle:
the white rear blind and the brown seat blanket - both of rather stiff and brittle pvc - ready to be welded and glued to the seat base - and finally riveting to the steel frame.
Two days later, the brake cable was shortened by some 10cm, to keep clear off the bell and make a nice radius between steel grip and stamp-type front "brake".