VintageLOTUSbicycles.com 

What year is my Lotus?

Good question.

The short answer is that it takes a bit of detective work to date your vintage Lotus. Many bike builders code the date of  manufacture into the serial number of the frame, but Lotus serial numbers seem to be proprietary and we have yet to break all of the codes.

Lotus literature is difficult to find and we don't have a catalog for every year of production. We are constantly searching for information and many readers have helped find old catalogs and sales literature. We'd like to thank Joe B, Ryan L, Eric P, John C, and Kent M once again for taking the time to scan and copy Lotus information for us.

If you have access to any Lotus literature or memorabilia and would like to help the website, please contact us.

Hopefully, using the Model pages on this website will at least help narrow down your choices and target you within a year or two of when your bicycle was made.  Many pages have photos and specification charts that can be used to narrow down the year of your bike by using significant details as a comparison.  For example, some bikes were made for a few years, but were only available one year in "Raspberry Pink".

We also use the term "generations" when it comes to dating Lotus bicycles, as sometimes a specific model, like the Excelle, was made for 10 years. During those 10 years the model changed significantly enough to be considered a different generation four times. Knowing the generation your model falls in will help narrow down the year it was made. 

If you check out the Serial # Chart, you may be lucky enough to have a serial number close to a bike that has already been dated.  The two-letter prefix found on many serial numbers does seem to represent model years, or ar least production runs.  For example, we believe the prefix KY represents 1980 production for at least the Legend and the Classique.

Most Tsunoda-built Lotus serial numbers are stamped onto the underside of the bottom bracket and consist of two letters followed by five, six, or seven numbers (AB12345++).  It seems that later model bikes have more numbers than the earlier bikes. This may be an important clue to dating a vintage Lotus. Some bicycles have been observed with serial numbers stamped on the seat tube near the bottom bracket. We are collecting a list of models and serial numbers in an attempt to make heads or tails out of the numbering system.  Please view the chart and feel free to submit your own information at the bottom of the Serial # Project page.

If you have a Pacific Cycles built Lotus Elite, Elan, Special, Sprint or Prestige your serial number will begin with the letter P, as in the example shown below on the Lotus Elite. P stands for Pacific Cycles.  The second number represents the year of manufacture and the third and fourth number, the production week. The final numbers are the individual frame numbers. So number P3151234 was the 1234th frame number built during the 15th week of 1983.

Some Lotus bicycles built in 1986-88 use a Y6C1234 style code.  The first letter is possibly a vendor code, the second number is the model year and the third letter is probably a fortnight code. C represents the 3rd fortnight of 1986 production.

We know that Lotus bicycles were built by many different factories to Lotus specifications. If you view the chart, specific numbering styles are starting to appear.  Each different numbering style may represent a different factory. So far we know that Lotus used Tsunoda, Pacific Cycles and Maruishi to make their bikes.

Lotus Serial Number Under Bottom Bracket

Dating components*:

Many bicycle components are stamped with a manufacturing date code, usually just a simple letter or number combination. Dating the components on a bicycle should help determine it's age. We prefer to use the seat post codes as we feel the odds of a seat post being replaced during the life of a bicycle is less than that of other components more subject to wear. Plus, the multiple sizes used for vintage seat posts makes it inconvenient to swap one out just for the heck of it.

Lotus favored SR (Sakai/Ringyo) for their early 1980's seat posts. SR stamped the date of manufacture under the minimum insertion line along with other information such as the post diameter. The sequence usually looks like this:

SR Seat Post Production Date Code

In this case C-83 is the manufacture date of the seat post. "83" is the last two digits of the year 1983  and "C" is the 3rd letter of the alphabet which corresponds to the 3rd month of the year, March. Thus, the post was made in March (so the bike could not have been assembled before then) and the bicycle is probably a 1983 model. Given the Japanese affinity for "just-in-time" inventory control, one can safely assume the parts at the factory didn't sit around too long before being put onto a bike in production.

Shimano uses a two letter dating system for their components. If you examine most any Shimano part close enough, somewhere on that part is stamped or cast a two letter combination.  The first letter is the year of manufacture with "A" being 1976 , "B" being 1977 etc.  The second letter is the month code, starting with "A" for January.  For example, a component stamped with an FD was made during 1981 (F) in the month of April (D).

Suntour has a similar system of dating to Shimano except "S" is now 1976, "T" is 1977 etc. The second letter is the month and it's the same code as Shimano, starting with "A" for January.  A Suntour component stamped XD was made during 1981 (X) in the month of April (D). When you get to "Z" for 1983 the alphabet starts all over again with 1984 represented by the letter "A".

Suntour Derailleur Production Date Code

Between SR, Suntour and Shimano you should have enough components on your bike to help localize the year it was made. If you need more information on dating bicycle components, the fine folks over at Vintage-Trek.com have assembled a very comprehensive guide called,

"Date of Manufacture for Bicycle Components" (opens in new window)

There they cover more component manufacturers (Campagnolo, Dia Compe, Sugino, etc.) and they also have tables and charts that are easy to read.  Eventually, you will get tired of reciting the alphabet and counting on your fingers trying to figure out what letter represents 1987 on your Suntour derailleur.
 

*Component date coding information courtesy of Vintage-Trek.com.  Photos, VintageLOTUSbicycles.com
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