Date of Manufacture for Bicycle Components

[SR (Sakae)] [Dia-Compe and Weinmann] [Campagnolo] [Maillard] [Shimano] [Strong]
[Sansin] [Sunshine] [SunTour (Maeda)] [Sugino] [Williams] [Dancing Chain] [Saddles]

The date of manufacture of a bicycle's components can often be used to determine the date of manufacture of the bike itself. Some bike parts have a date code cast or stamped into the piece. This clearly is when the component was made and not when the bike was made, but unless the component or bike manufacturer had lots of stock lying around in inventory, the date should be a fairly good indication of the year of the bike. At least it would be the earliest date that the bike could have been made. Of course, all this assumes the bike has the original component.

A date code is marked on most or all SR seatposts. Trek owner Larry Osborn made this observation, and suggested this as a supplementary way of dating a Trek (and other bikes as well). Fueled by this first realization, and with the help of other bike folks, Larry and I have sorted out other codes (a project still ongoing). Especially useful, and challenging to sort out and verify, was the Shimano code. Also gathered on this page are date codes provided by others.

For Treks, the SR date markings are especially important. Virtually all of the Treks not equipped with Campagnolo or Shimano Dura-Ace components, started life with some grade of SR seatpost and may also have SR stems, bars or cranks. Even those equipped with Suntour Superbe components usually had SR seatposts.

Many components are marked with size descriptors in addition to component manufacturer's date codes. For example, the back of cranks are usually marked with crank arm length in mm, typically in the range of 165 to 185. Seatposts are marked with outside diameter, also in mm. For old Treks, 27.2 is the most common, but for other bikes the diameters can range from 25mm to 33mm.

A NOTE ABOUT ATTRIBUTION: Feel free to copy the information on this page, but we do ask that you include Vintage-Trek.com as the source. In this website we have made an effort to credit the people involved in the development of these codes. Naturally, for information provided by others, such as for the Campy and Williams codes, we suggest the original source be cited.

Request for Information

This component dating discussion is a work in progress. If you have confirmation of the date codes, or corrections or additions to the codes, please contact me.

Other manufacturers of bicycle components have date marks on their pieces. Unfortunately, many of these are coded, and require some additional knowledge to understand the code. If you know of other components that are marked or coded that can be added to this list, please let me know.

SR (Sakae)

Below the insertion mark on SR seatposts (and Sakae posts) is a stamped mark, such as F-84. The number is the year of manufacture and the letter appears to be the month of manufacture. In the example, the "F" indicates the sixth month, or June.

Steve Mann reports a mid 70s SR seatpost which is marked with a date code of the form 76.9, where 76 is the year and 9 is either a fractional year or the ninth month of the year.

Most SR right crank arms also have an open date marking, either stamped or cast into the arm. The date is on the back side of the arm near the spider of the crank, typically of the form of the two-digit year above a letter, apparently representing the month.

An SR Custom crankset, reported by Alan Burnett, has the back of one arm marked only with a 1 and the other arm with a 2. This crankset came on a 1982 Trek 412. Alan suggested, like for Campy crankarms, these are the last digit in the year; i.e. 1981 and 1982. Does anyone have a similarly marked set of SR cranks?

SR stems usually are marked with the same date code. It appears near the insertion mark. An exception is the SR Royal stem, most - or all of which, have no code.

Most (all?) SR handlebars have the date code stamped near one of the ends of the bar.

Dia-Compe and Weinmann

Thanks to Ben Weiner for sending the following information about Dia-Compe and Weinmann brakes.

Ben writes: "Brakes and brake levers often have date codes on them. Weinmann and Dia-Compe calipers usually have codes on the back of a caliper arm. This can be simple like "0784" (month 07, 1984) or a clock-type, with year in the middle and a ring of numbers with a tickmark pointing to the month."

"Dia-Compe road levers usually have a code stamped _inside_ the lever. Pull the lever and look inside the top of the lever arm for a code such as "1084." Dia-Compe extension levers (yuck) also tend to have date codes on the side that faces the brake hood. I have a set of Dia-Compe mountain levers where if you pull the lever all the way, a piece of the lever is exposed, which has a clock-type date code. Dia-Compe cantilever brakes don't appear to have a date code, but supposedly the 981, 983, 986 brakes were first introduced in 1981, 1983, 1986, etc."

Following Ben's lead - I checked three sets of Dia-Compe G calipers and all have the four-digit date code on the back of one of the arms. The two sets of Dia-Compe brake lever bodies I checked had the four-number date code stamped inside the lever body (I couldn't find any markings on the levers themselves). However, a Gran Compe set of calipers had no markings.

Campagnolo

The dating of Campy components (hub lock nuts, rear derailleurs, and cranks) is described at the bottom of Chuck Schmidt's excellent Campagnolo timeline:
http://www.velo-retro.com/tline.html

Maillard Hubs

Maillard used an open dating system for their hubs. It is of the form NN NN. The first pair of numbers is the numerical week of the year, 01 to 52. (Thanks to Erik Frey for providing this information). The second two numbers are the year of manufacture (e.g. 84 for 1984).

Shimano

Shimano components have a two letter date code, in the form XX, where X is a capital letter. A friendly Shimano representative told me the code is not public but he was able to answer some of my questions. One letter is the month, the other is the year. He thought all Shimano components use a common code. Some Dura-Ace seatposts are stamped with a two letter code of the form X-X, where X is a letter. The Shimano representative believed this is the same meaning as the more typical form XX.

The date code is stamped (or cast?) into the component and appears separately from other markings. It is easy to confuse the date code with the alphanumeric model number (e.g. "HB-6500" marked on an Ultegra hub). The code is on the outer flange or the center shaft of hubs, on the backside of crank arms, and below the insertion mark on (at least some) seatposts. On crank arms, the letters may appear as about 3mm tall and enclosed in a circle. On at least some rear derailleurs the date code is stamped on the inner face of the outer part of the cage. On at least some headsets, the code is stamped on the underside of the fork crown race, and it is visible when installed.

The first letter represents the year and the second is the month, where A is January and L is December. For the first letter A is 1976 and the letters proceed sequentially from there: K is 1986 and Z is 2001. Year 2002 restarts with A.

Shimano Year Code

A	B	C	D	E	F	G	H	I	J	K	L	M
1976	1977	1978	1979	1980	1981	1982	1983	1984	1985	1986	1987	1988
2002	2003	2004	2005	2006	2007

N	O	P	Q	R	S	T	U	V	W	X	Y	Z
1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001

Shimano Month Code

A	B	C	D	E	F	G	H	I	J	K	L
Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec

Here are some observations regarding Shimano dates (provided by Tom Marshall):

1. "Front derailleur codes are generally on the frame side of the inner cage plate.

2. "Bottom bracket codes are on the outside of both cups and on the spindle."

3. "Down tube shift lever codes are generally on the backside on the SIS hub."

4. "Codes for STI road levers are generally cast into the medial side of the body. You should be able to see it by peeling back the hood from the handlebar end. On some models there may also be another date code on back of lever's tip."

5. "On dates which can be read backwards (upside down) Shimano underscores the date code."

6. "The 1992 code "Q" has a backslash (\) through it to distinguish it from the 1990 code "O" (Oh).

7. "Pre-76 hubs appear to have a single year letter code (without the month designator). A hub I have has a Y which I assume is 1974, which matches my estimated age for the hubs."

Ben Weiner pointed out a very useful site concerning Shimano components. For each component model, it gives the years in which that model was sold. These pages are through the efforts of the Specialized Technology Committee of the Allgemeiner Deutscher Fahrrad Club: http://www.fa-technik.adfc.de/Hersteller/ It is in German, but years and model designations are effectively in English. If you like, use the web site translation function on the AltaVista.com web site.

Shimano/SunTour Freewheel This interesting note was sent in by a site visitor:
"A 1970s, Shimano 5-speed freewheel (15-24t) has code "RA" stamped near one of the spanner pin holes on the face of the locking plate. "R" for Shimano would be 1993, but "R" for Suntour would be 1975, therefore I suspect this is a Suntour made freewheel, but labeled "SHIMANO 3.3.3.". There is also an "S" stamped separately on the face, perhaps standing for Suntour?"

This nice piece of detective work means that if a Shimano (or other) date code seems to provide the wrong year, look carefully to see if another manufacturer might have made the part.

Strong Seatposts

Seatposts made by Strong typically have a two digit numerical year date stamped into the post below the insertion mark.

Sugino Cranks

Sugino has used at least five codes for their cranks. The codes appear on the inside face of each crank arm.

Code 1 - Beginning in the early 80s, a stamped code of the form LN or LNN was used, where L is a letter and N is a number. We believe the letter is the year code, where A is 1981 (or 1982 or perhaps 1980), B is the next year, and so on. The N or NN is a number from 1 to 12, representing the month. This system was used on model AT cranks, commonly used by Trek in the early 80s.

A	B	C	D	E	F	G	H	I	J	K	L	M
1981	1982	1983	1984	1985	1986	1987	1988	1989	1990	1991	1992	1993

N	O	P	Q	R	S	T	U	V	W	X	Y	Z
1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006

Code 2 - In the 70s and perhaps earlier, a stamped code of the form NN-N or NN-NN was used. We believe the initial NN is a year code with 46 = 1971. The number after the dash is a month code. This code was used on Mighty Comp models. Andrew Chadwick reports having a Sugino Maxy crankset with a variation of this code: "The dates are stamped "49.5" on the inside of the right crank arm, and "49-5" on the inside of the left. The former is definitely a period/full stop/decimal point, and the latter is definitely a hyphen." The right hand (crank maker) does not know what the left hand is doing?

Tom Marshall provides this description of the NN-NN Japanese codes: "The Sugino codes with format NN-NN appear to be based on the Japanese Imperial Calendar. Whenever a new emperor took the throne, a new era was officially declared. On December 25, 1926 Emperor Hirohito ascended to the throne and chose the the name Showa (radiant peace) for his era. It ended on January 07 1989 when Akihito took the throne and the Heisei (peaceful accomplishment) era began. Thus 1926 is year 01 of the Showa era, 1927 is year 02, up to 1989, which was Showa year 64 and Heisei year 01."

"I stumbled across this when I was trying to decipher the 47-12 and 48-1 codes on the Sugino crankarms from a mid-70's CCM Mistral. It seemed pretty obvious that it was a YY-MM (year- month) format, but the years were skewed. A little investigation into Japanese culture turned up the logic in the preceding paragraph and when applied to my cranks, the manufacturing dates became December 1972 & January 1973. This was a perfect fit for the Mistral and seemed to apply to all the Sugino cranks I examined thereafter. The Japanese Imperial Calendar may well be the basis for date codes on other Japanese components."

Code 3 - A third set of codes (or no date code at all) was used on at least some GT and VX cranks. There is a round mold mark with three numbers in it. There also may be a cast-in code of a number and perhaps two letters. We don't have enough data on these codes to understand what they mean.

Code 4 - A forth code method was reported by Mike Swantak. His ’83 Centurion Le Mans 12 has a Sugino GT crankset, with the two letter code GC. This would appear to follow the method used by Shimano, where the G indicates 1982 and the C indicates March. This is supported by Dan Carlsson of Sweden, who writes: "I have a Sugino GS crankset with the codes "GC" stamped on the inside. This seems right, 82 March; I believe the crankset is from an 1983 year roadbike."

Code 5 - Elisabeth Thomas-Matej reported a code of I-3 on the left crank of a Sugino "Tourist" crank on a 1979 Centurian Super LeMans. The I-3 is cast into a raised circle on the back of the crank. Also on the back are the letters: SUGINO FORGED JAPAN 170.

A 1981 Schwinn Le Tour Tourist equipped with a Sugino Super Maxy Crank was reported by Rich McCarthy. It was marked J11 on both crank arms. It is likely both cranksets above have the same form of code. The first letter is the year, with I=79 and J=80 (both plus or minus a year). The number is probably the month of the year. The N or NN is a number from 1 to 12, representing the month.

NOTE: If you have a bike of known year with a Sugino Crank with one of the above codes, or any codes, please send the information to me.

Sansin Hubs

Many Sansin hubs use a a two-letter date code. The code is stamped near the center of the hub body. The first letter represents the year. We believe A is 1984, B is 1985, and so on. (Is this correct? please let me (Skip) know.) As with Shimano, the second letter is the month code, where A is January and L is December. Sansin and Sunshine hubs were made by the same company.

A	B	C	D	E	F	G	H	I	J	K	L	M
1984	1985	1986	1987	1988	1989	1990	1991	1992	1990	1993	1994	1995

Sunshine Hubs

Many Sunshine hubs have an open dating code, of the form NN NN. The code is stamped near the center of the hub body. The first two numbers represent the month of the year; 01 for January, 12 for December. The second two numbers are the year of manufacture (e.g. 84 for 1984).

Sunshine and Sansin hubs were made by the same company. One Sunshine hub was marked only with an A, on a bike made in 84, which matches the Sansin year code.

SunTour (Maeda)

SunTour derailleurs have a two-letter date code. On rear derailleurs the code is stamped on the back side of the inner parallel arm. On front derailleurs it is stamped on the back side of the inner cage.

The first letter represents the year. Larry Osborn and I believe O (Oh) is 1972, V is 1979 and A is 1984. As with Shimano, the second letter is the month code, where A is January and L is December.

SunTour Year Code

N	O	P	Q	R	S	T	U	V	W	X	Y	Z
1971	1972	1973	1974	1975	1976	1977	1978	1979	1980	1981	1982	1983
A	B	C	D	E	F	G	H	I
1984	1985	1986	1987	1988	1989	1990	1991	1992

SunTour Month Code

A	B	C	D	E	F	G	H	I	J	K	L
Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec

The earliest Suntour derailleur I have found with a code is marked OF. A rear derailleur marked OD (corresponding to April of 72) was reported by Leighton Walter. I have a bike that dates from between 1970 to 1972 that has the original SunTour derailleurs. These derailleurs do not have date codes on them, so I believe the coding started sometime between 1970 and April of 1972.

Tom Marshall writes: "Maeda/SunTour freewheels appear to have a date code, format LL, on the outer cover plate, adjacent to one of the pin holes. The original freewheel from my 1974 CCM Tour de Canada is stamped PA. I assume P =1974 or possibly 1973). This seems to mesh with the derailleur codes above."

Shimano freewheels made by SunTour - see Shimano/Suntour Freewheel above.

Williams (Great Britain)

See the Williams components dating information provided by Hiliary Stone and shown on the Classic Rendezvous web site.

Derailleur Dates in "The Dancing Chain"

The rear derailleur can often be dated to a year or two by referring to the book "The Dancing Chain - History and Development of the Derailleur Bicycle", by Frank Berto, Ron Shepherd and Raymond Henry, 1999. The Appendix gives dates of initial manufacture for the vast majority of derailleurs made from 1920 to 1999.

Saddles

Brooks Saddles - Prior to sometime in the 1960s the inside of leather side flaps were stamped with a date code. The stamp denoted the month and year of manufacture. Mrs. O'Donnell* writes: "Unfortunately, the "code" book is now lost so we cannot decipher the actual codes used at that time. It is, sadly, not quite as simple as A=January, B=February etc. This 'flap' stamping changed to the frame stamping around the 1960's although there was an 'overlap' period where both the leather and the frame were stamped."

The metal frames of the saddles were stamped with the date of manufacture from sometime in the 1960s to about 1988.

The current method of stamping Brooks saddles is a colored stamp on the underside of the saddle, with a number for the year surrounding a letter for the month.

(*The above Brooks information was provided in an e-mail from Mrs. E. O'Donnell in the Sales Department of Sturmey-Archer, when that company owned Brooks. Mrs. O'Donnell was writing to Robert Williams in response to his query about date codes. Our thanks to these two individuals and to Larry Osborn, who secured a copy of the original e-mail.)

Plastic bicycle saddles (seats) often have a date code molded into the underside of the plastic core of the seat. The mark is made up of a circle with the first letter of the month (in Italian or just a number) around the edge, with the two-digit year code in the center. An arrow points to the month the product was made. (Thanks to Grant McLean for this observation.)

Those saddles without a code on the underside may have the code molded into the top of the plastic molded core, hidden by the seat cover. However, finding the code may be hard on the saddle. ;-)

 

[SR (Sakae)] [Dia-Compe and Weinmann] [Campagnolo] [Maillard] [Shimano] [Strong]
[Sansin] [Sunshine] [SunTour (Maeda)] [Sugino] [Williams] [Dancing Chain] [Saddles]

 

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