Many vintage road components carry a stamp that tells you roughly when they were made. That matters if you're building a period-correct bike, matching a groupset to a frame's year, or checking whether a "1975 Nuovo Record bike" really wears 1975 parts. But a date stamp only tells you the earliest the part could be. Shops stocked parts for years, bikes were assembled long after their parts were made, and owners swapped components for decades. Treat a stamp as one piece of evidence and weigh it against the part's design details.
Campagnolo Nuovo Record and Super Record rear derailleurs
The best-known scheme is the patent wording on the upper body (the b-knuckle) of the Nuovo Record rear derailleur. Disraeli Gears gives this rough summary:
- 1966–1967: "PATENT CAMPAGNOLO"
- 1968–1969: "PATENT" with no year
- 1970–1979: "PATENT-70" through "PATENT-79"
- 1980–1984: "PAT.80" through "PAT.84"
- 1985: "PAT.11"
- Later: examples with no wording at all, such as one Disraeli Gears places around 1986
Two cautions come from the same source. Between 1966 and 1969, Campagnolo changed the design without always changing the wording, so a plain "PATENT" derailleur can be any of several versions and needs dating by its details, such as the pulley wheels and the pivot spring. From 1970 to 1985, the design changes seem to line up with the yearly stamps. The Vélo-Rétro Campagnolo timeline agrees that dated stamps start in 1970, with plain "PATENT" before that.
The Super Record rear derailleur (introduced in 1973) follows the same pattern: "PATENT-73" to "PATENT-79", then "PAT.80" to "PAT.84". The Vélo-Rétro timeline says "PAT.11" (1985) was the last dated Super Record, and later ones are undated. The odd "11" matches the half-year codes Campagnolo used on its cranks from 1985 (see below).
Two practical points for buyers. First, the knuckle can be swapped: a derailleur rebuilt from spares can carry a stamp from a different year than its cage or plates. Second, the stamp doesn't distinguish original from refinished, so look at the whole part, and read spotting reproduction Campagnolo if a "PATENT" example looks too clean.
Campagnolo crank arm codes
According to the Vélo-Rétro Campagnolo timeline, Campagnolo crank arms carry a small stamped date code from 1973:
- 1970s: a diamond with a single digit for the last digit of the year, so a 6 in a diamond means 1976.
- Around 1980: a circle with a single digit.
- 1981–1984: a square with two digits, from 81 to 84.
- 1985–1991: half-year codes in a square. 11 and 20 are the first and second halves of 1985, 21 and 22 are 1986, 31 and 32 are 1987, 41 and 42 are 1988, 51 and 52 are 1989, and 61 and 62 are 1990. 71 is the first half of 1991 and A1 the second half.
- 1992–1994: A2 for 1992, then 93 and 94.
This is useful on a Nuovo Record or Super Record crankset, which looked very similar for years. Ask the seller for a clear photo of each arm's code, because the left and right arms of a "set" are often from different years. A pair a year or so apart is normal. A pair a decade apart was put together later.
The same timeline notes that Campagnolo hub axle locknuts are typically stamped with a two-digit year, for example "CAM. 60". That gives you a cross-check on Record hubs, but locknuts are small and easily swapped, so give it less weight than a crank code.
Shimano two-letter date codes
Disraeli Gears describes Shimano's dating like this:
- 1950s: some derailleurs carry a Japanese imperial-era date. "32.1" means January of the 32nd year of the Showa era, which is 1957.
- From about the 1960s: two capital letters. The first letter is the year and the second is the month, with A for January, B for February and so on. In the early scheme, K was 1965, L 1966 and M 1967.
- Later: Shimano restarted the year letters so that A was 1976, B 1977, C 1978 and so on. The month letter didn't change.
Under the later scheme, I is 1984, J 1985, K 1986, N 1989 and U 1996. That fits the dated examples Disraeli Gears shows. A first-version Dura-Ace 7400 rear derailleur coded JI is September 1985. A 7401 coded KK is November 1986. Two 7402s are coded NF (June 1989) and UE (May 1996), and a 600 EX derailleur is coded IF (June 1984).
There are two limits. The year letters repeat, so K can mean 1965 or 1986, and you need the part's model to know which. And the code dates that particular piece, not the bike it came off. On derailleurs it's often on the body near the upper pivot, and other Shimano parts like cranks, hubs and brakes often carry one too. Look on the back of a 600 crank arm or the body of a Dura-Ace caliper.
SunTour two-letter date codes
Disraeli Gears says SunTour stamped no date codes in the 1950s and 1960s and adopted a two-letter code around 1971. The first letter is the year, counted so that A would be 1958, N is 1971, O is 1972 and P is 1973. The second letter is the month, with A for January. The code was often stamped on the rear parallelogram plate.
The sequence wraps after Z (1983), which matches Disraeli Gears' dated mid-1980s examples. A Cyclone Mk II coded AH is dated 1984, and a Superbe Pro coded BJ is dated 1985. So AH reads as August 1984 and BJ as October 1985. Disraeli Gears also suspects the code may record when the plate was made rather than when the derailleur was assembled, so allow a little slack either way.
Mavic, Brooks, Cinelli and 3ttt
We couldn't find a documented, reliable date-code scheme for Mavic rims, Brooks saddles, or Cinelli and 3ttt bars and stems in the sources we trust, so we won't offer one. Date these by model, labels and logos, construction details and period catalogs. Be wary of listings that "decode" a stamp on a GP4 rim or a B17 to an exact year without showing where the scheme comes from.
Using dates when you buy
- Ask for close, sharp photos of the stamp itself. "It's a 1976" in the title isn't evidence.
- Check that a part's design details match its stamp. A derailleur's pulleys, bolts and cage should belong to the year on the knuckle.
- For a period-correct build, aim for parts dated at or a little before the frame's year, not after it.
- Don't pay extra for a "matching year" set unless every piece has been photographed and checked.
For which parts physically fit together, see vintage road component compatibility.
