How to determine age and manufacturer of a Long John bike (and other Danish bikes)
Most Long John owners would like to know age and manufacturer of their bike. On Danish bikes you´ve got a good chance to get this information by analyzing the serial number. In 1942 Denmark introduced a nationwide sytem of serial numbers for bicycles and mopeds which encodes both the manufacturer and the year of manufacture.
Where to find the serial number
On Long Johns the serial number can be most likely found in one of these locations:
1: on left side of the top tube (SCO, Monark)
2: on left side of the seat tube (older SCO and others)
3: on the steering tube (Monark)
4: upper side of chain stays, between bottom bracket and rear wheel (Esimex)
Other popular locations for serial numbers on bicycles are under the bottom bracket and on the rear drop-outs.
Maybe you won´t find a (valid) serial number for one of the following reasons:
-the bicycle was built before 1942 when serial numbers weren´t mandantory in Denmark
-the number (or parts of it) got lost due to abrasion, scratches, corrosion or any other damage
-the number (or parts of it) is covered with paint
-it´s not a Danish bike or not build for the Danish market
Serial number on the seat tube of a 1955 SCO Long John.
Decoding a serial number
| |
imp. |
manuf. |
seq. nr. |
yr |
| serial nr: |
W |
BK |
12345678 |
B |
imp.: Imported bikes (not made in Denmark) are marked with "W", otherwise this field is left blank.
manuf.: letter code indicating the manufacturer or importer (1-3 letters, see list below)
seq. nr.: sequential number assigned by the manufacturer (up to 8 digits)
yr: letter code indicating the year of manufacture (see list below)
Note: Serial numbers of Danish bikes built before 1942 don´t necessarily meet this specification. The same applies to Monark Long Johns produced for the non-Danish market.
Manufacturer codes
Every single manufacturer/importer has its own official and unique letter code(s). Since 1942 there have been several hundred manufacturer codes in use. Some of them are listed here:
| A | Harly Bech Sørensen, Silkeborg |
| AA | Anton Nielsen A/S, Århus |
| AV | A. Winther A/S, Them |
| BB, BK | Børge Kildemoes Cykelfabrik A/S, Nr. Lyndelse (dänischer Importeur von Monark Long Johns) |
| BP | Bohnstedt Petersen A/S, København |
| BT | Taarnby A/S |
| CF | Cykelhandlernes Centralforening, Brabrand |
| CK | Jensen cykler (C K Jensen) |
| EE | Egedesø, Odense / Everton, Nørre-Åby (1995 aufgekauft durch Smith & Co) |
| G | Dansk Cykelværk Grand A/S, Nørre-Åby |
| HM | Haderup Maskinfabrik, Haderup |
| LL | Sorte Jernhest |
| MB | MBK cykler |
| N | Nordisk Cykelfabrik A/S, København |
| OC | Otto's Cykler, Dragør |
| PS | Schrøder cykler |
| R, AR | Vilh. Nellemann A/S, Risskov |
| S, SS | SCO (Smith & Co), Odense |
| SX | Saxil cykler |
| TV | Batavus |
| UR | Urania cykler |
| VEL | Velorbis, København (seit 2007 dänischer Distributor von Monark Long Johns) |
| VG | Grebart cykler |
| XX | Esimex, Hanstholm |
(Caution: this list might possibly contain flaws)
Year codes
The last digit of each serial number is a letter matching the year of manufacture. Since there are less letters than years all letters are re-used in cyclic intervals. See list:
| A | 1942 1964 1985 2006 | | J | 1950 1972 1993 | | S | 1958 1979 2000 |
| B | 1943 1965 1986 2007 | | K | 1951 1973 1994 | | T | 1959 1980 2001 |
| C | 1944 1966 1987 2008 | | L | 1952 1974 1995 | | U | 1960 1981 2002 |
| D | 1945 1967 1988 | | M | 1953 1975 1996 | | V | 1961 1982 2003 |
| E | 1946 1968 1989 | | N | 1954 1976 1997 | | X | 1962 1983 2004 |
| F | 1947 1969 1990 | | P | 1955 1977 1998 | | Z | 1963 1984 2005 |
| G | 1948 1970 1991 | | Q | 1956 | | | |
| H | 1949 1971 1992 | | R | 1957 1978 1999 | | | |
The letter Q was only used once (in 1956). The letters "O", "I", "W" and "Y" have been completely dropped, mainly to avoid confusion with similar letters and numbers.
Since a single letter code can match up to four different years you´ll need additional information on your bike to determine the exact age. The frame itself can give some hints on the production period.
Frame Designs
Long Johns have been produced for many decades, and they appeared in several different frame designs. Below you'll find some drawings of Long John frames. The drawings are schematic, simplified, NOT detailed and NOT true to scale. As far as available information about age and manufaturer is added. This list of frames is in no way complete. Any additional information, corrections and help (especially pictures of old Long Johns) on this subject would be appreciated!
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Manufacturer: Nordisk Cykelfabrik(?)
Year: unknown, possibly early 1940s. |
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Frame versions of unknown origin and age. I´ve seen these on internet auctions. More info needed (e.g. serial numbers)! |
No pictures available.
Do you have one?
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Manufacturer:SCO
Year:1948(?), 1951 |
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Manufacturer: SCO
Year: 1955 |
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Manufacturer:SCO, often sold under the label URANIA, maybe also under other labels
Year: 1967
This kind of frame has been built until the early 1970s (at least until 1972).
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Manufacturer:SCO, also sold under the label URANIA
Year:mid or late 1970s
Does anyone have this frame type WITH serial number?
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Manufacturer: SCO
Year: 1991
Frames of the 1980s had the same design (more or less) |
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Manufacturer: SCO (until 1997), then Monark, Sweden
Year: mid-nineties until 2003
Frame design is also in use on the new "Velorbis" Long Johns (since 2007).
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Thanks to Jimmi Johansen, Lars Evdokiyos, Giles Butcher und Alan Nielsen for their pictures on this page.
Additional links regarding this subject:
