At some time late in each year (beginning generally September or October) the frames produced were created from designs, and painted with colors, for the next year. In this case I used a red candle to make the serial number stand out.
"Rub the area with candle wax of a color that contrasts with your paint. Note that even with the serial number filled with wax, the leading "0" is almost imperceptible."Before late 1980, Trek used an alphanumeric serial number scheme.
The dates coded in the serial numbers, or the dates inferred from the numbers, are dates on which the new frames were stamped with serial numbers (serialized).
Many early Trek bottom bracket shells have a one or two letter code stamped separately from the serial number.
This was made by the individual framebuilder to mark his/her work.
A couple of serial numbers have been submitted that are missing the first letter. For example, a 710 frame made with Columbus tubing instead of 531. The last letter might be a run designation, with the last two numerals the frame number in that run? Hence the change to the sequential system that was started in late 1980.
Alternatively, the letter extends the range of the character from 0 to 9 (if a number) to 1 to 26. There is no Model 310 in the brochures on the site; however, a frame has been reported that has Ishiwata high tensile double butted main tubes with the SN A4F9H67. According the the SN, it apparently was made in June 1979, after the TX300 is no longer in the brochures, but no similar frame is listed.
On some bottom brackets there are two codes: one indicating the maker of the main triangle and the other for the maker of the rear triangle or perhaps the person who cut and shaped the tubing, if not done by the framebuilder.
If you know which mark was used by a particular craftsman, please let me know. This Streamliner is owned/restored by Nathan Pence and was painted by Dave Stromberger. The 1937 Roadmaster Supreme is one of the most desirable pre-war bikes. and badged as a La France, this streamlined, art-deco styled bicycle was a top-of-the-line machine, even though it didn’t feature a tank… It features the motorbike style frame with truss fork, Persons leather saddle, cross brace handlebars and of course, a Miami built….This applies only to serial numbers in the form LNLNLNN where the first letter is an O (Oh).This does not apply to the all-numeric serial number form that began in late 1980. For these all-numeric numbers with a leading zero, see LATE 1980 to LATE 1986 below. It appears that some custom frames were built that did not fit within the standard model description. The last three characters - The final letter ranges from A to Z and the final two numbers go from 01 to 99. Perhaps once Trek was nearing more than 2600 bikes/frames of a given model per month, a new serial number scheme needed to be developed.Each seven-character number consists of three letters mixed with numerals.