Hey all. I recently acquired this Centurion LeMans and need your help dating it! Centurions can be more easily dated if they are '80s models and newer because of their colour schemes and serial numbers. According to Sheldon Brown,

Japanese Centurions made between 1980-1990 use a serial number format WXYZZZZ where:

W = a letter, purpose uncertain, but probably indicates a manufacturer or Centurion;
X = a number, indicating the calendar year of manufacture;
Y = a letter, indicating the fortnight of manufacture (A = wk 1 & 2, B = wk 3 & 4, etc)
ZZZZ = four digit number, probably indicating frame number during fortnight of manufacture.




Grimy drivechain, I know.


Example: N4E0283 indicates the 283 frame made during the period of weeks 9-10 in 1984.

My bike has this serial number: NB87571, which does not follow this format. I think it might be a mid to late '70s model, but if anyone has any information that can narrow it down to the year, I'd really appreciate it!

Note: 1979 LeMans were apparently 12-speeds, according to the 1979 catalog. However, mine is a 10-speed. Otherwise, the design and some components seem to match up.

1983, I think, went decal vs. headbadge, so it's pre-that.
Your headbadge is the same as a 1979 model, so figure 1979 or earlier.
Most models in 1979 were 2x6, so you can use that as a guide, perhaps.
Graphics match late 70's, early 80's.
That bike will really pop if you completely disassemble it, and then clean/shine each chrome part with 0000 steel wool, polish it up, go after the frame with WD40, elbow grease.


A drive side pic would help, and the components can surely help date it.

It's a 1978 model.

Here are some new pictures from recently. I'm starting to think it's a '79 model with different a different freewheel.

Suntour VX Derailleurs

Makes sense. Do you know if '78 models had 5 speed freewheels?

Nishiki came out with the Olympic 12 about late 1977- early 78, Centurion was quick to market trends, I would not be surprised of a mid cycle change to 6.

The Niko bikes (Bikecology house brand) actually came out with the color co-ordinated cable housings, tape, saddle coverings first, Centurion was quick to respond- so quick that we felt there was corporate espionage.

it was a competitive time.

My guess would be a 1979 Model. as it looks like the 78 models had the earlier badge. and the 1979 model Lemans had a 6 speed freewheel.

here is the 79 catalog

https://vintage-centurion.com/literat...on_Catalog.pdf

It probably didn't hurt that Alan Goldsmith was associated with both Bikecology and Centurion at the time.

He negotiated the Cinelli deal with Centurion, and had a hand in the last 3-4 years of the Ironman.

He later got involved with ParkPre. Last I heard, he was also involved with Specialized (in his 80's).

I have an April 1979 comparison test stating that the Le Mans employed a 5 speed freewheel, specifically 14-17-20-24-30T. Given the time to get an article to print during the era, the test may have been conducted using 1978 models. Consequently, it would appear that the Le Mans was 10 speed through at least 1978 and there is a good probability that the current freewheel is OEM.

If the OP wants a higher degree of confidence regarding the originality of his freewheel (and the model year of the bicycle), he can start checking component date codes using the information here; Date of Manufacture of Bicycle Components can be used to date a bike: component dating . I suspect he'll find late 1977 to very early 1978 date codes, which would be consistent with a 1978 model.

Interesting T Mar, Does the bike in the article have the round headbadge or the earlier style?

very cool that the tubing badge includes the butting measurements.

There weren't any pictures for the bicycles included in the article.