Bridgestone serial numbers decoded.
01-05-22, 03:46 PM
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Bridgestone serial numbers decoded.
I have been collecting and cataloguing bicycle serial numbers for more than a decade. I started to do this because I was trying to determine the age of certain bicycles that I was repairing. I was also not fully satisfied with descriptions of manufacturers serial numbers that I found on the internet.
Bridgestone serial numbers are one such example for which I have not been able to find a satisfactory description.
I have catalogued more than 140 serial numbers of Bridgestone manufactured bicycle frames, not including custom builds and contract bicycles for Schwinn.
The serial numbers are mostly of two formats based on the first two characters:
Number + Letter
Letter + Number
The number is considered to be for the year of frame manufacture.
The letter is considered to be far a time period with in the year.
What is the time period within the year?
One clue is the distribution of the letters used for time period.
There are 26 letters in the alphabet.
The letters "I" and "O" are not found in my data.
Most of the letters found are in the range A to L (except I) and X.
With the exception of the letter "X" very few letters are found beyond the letter L. There are enough of these letters found that they cannot be ignored or considered to be errors. If these letters represent the second half of the year, then the majority of Bridgestone manufacturing occurred in the first half of the year.
This seems unlikely to me, because serial number data shows that most manufacturers do the majority of their production in the second half of the year.
Hmmm? What can the letters represent?
In my quest for answers to questions about Japanese bicycle manufacturing and distribution I began looking at Japanese websites. I have found a lot of interesting details about the Japanese bicycle business.
Recently I found a blog that had a set of posts about an individual Bridgestone bicycle. This blog directed the reader to another blog with posts from the year 2012 about Bridgestone bicycles. The second blog is by Demo Tori-san (which I hope is a good translation.)
Demo Tori-san has done some good research concerning the Bridgestone Bicycle company and dating with frame numbers.
Here are some links to the 2012 blog posts:
BS frame No.
- this link includes comments from blog readers.
BS frame No. - factory models
BS frame No.- post collection
The rule of BS frame numbers:
The blog is in Japanese, so for English readers here is a google translation of the essential finding by Demo Tori-san and other followers of the blog.
It should be noted that Bridgestone had more than one manufacturing facility and custom order frames used other serial number formats.
Alphabet + numbers = Asahi Factory. Asahi factory = sports vehicle
Number + Alphabet = Ageo Factory. Ageo factory = general vehicle
Custom Order frames, like Grand Velo, custom-made production section in the Ageo factory.
it is the law of A to L = January to December, but if the monthly production exceeds 99,999 units, the alphabet will be moved up. Isn't it?
In the list,
A = January
B = February
C = March
D = April
E = May
F = June
G = July
H = August
X = September * The order is <I>, but it is easy to be confused with 1. Use <X> as a special case.
J = October
K = November
L = December
Below this, if the monthly production exceeds 99,999 units
M = January
N = February
Y = March * Although it is <O> in order, it is easy to confuse it with O (zero), so use <Y> as a special case.
P = April
Q = May
R = June
S = July
T = August
U = 9 Month
V = October
W = November
Z = December * <X> in order, but since <X> and <Y> have already been used, it is speculated
that <Z> will be used in advance .
The above is my own guess, so please be careful not to make a mistake .
Demo Tori-san has also shown portions of many Bridgestone serial numbers to help illustrate his findings. The domestic Japanese models used a letter/number system to identify models, so you will not see familiar Bridgestone model names in the data.
For me, this is a more satisfactory description of Bridgestone serial numbers than I have seen anywhere else.
Bridgestone serial numbers are one such example for which I have not been able to find a satisfactory description.
I have catalogued more than 140 serial numbers of Bridgestone manufactured bicycle frames, not including custom builds and contract bicycles for Schwinn.
The serial numbers are mostly of two formats based on the first two characters:
Number + Letter
Letter + Number
The number is considered to be for the year of frame manufacture.
The letter is considered to be far a time period with in the year.
What is the time period within the year?
One clue is the distribution of the letters used for time period.
There are 26 letters in the alphabet.
The letters "I" and "O" are not found in my data.
Most of the letters found are in the range A to L (except I) and X.
With the exception of the letter "X" very few letters are found beyond the letter L. There are enough of these letters found that they cannot be ignored or considered to be errors. If these letters represent the second half of the year, then the majority of Bridgestone manufacturing occurred in the first half of the year.
This seems unlikely to me, because serial number data shows that most manufacturers do the majority of their production in the second half of the year.
Hmmm? What can the letters represent?
In my quest for answers to questions about Japanese bicycle manufacturing and distribution I began looking at Japanese websites. I have found a lot of interesting details about the Japanese bicycle business.
Recently I found a blog that had a set of posts about an individual Bridgestone bicycle. This blog directed the reader to another blog with posts from the year 2012 about Bridgestone bicycles. The second blog is by Demo Tori-san (which I hope is a good translation.)
Demo Tori-san has done some good research concerning the Bridgestone Bicycle company and dating with frame numbers.
Here are some links to the 2012 blog posts:
BS frame No.
- this link includes comments from blog readers.
BS frame No. - factory models
BS frame No.- post collection
The rule of BS frame numbers:
The blog is in Japanese, so for English readers here is a google translation of the essential finding by Demo Tori-san and other followers of the blog.
It should be noted that Bridgestone had more than one manufacturing facility and custom order frames used other serial number formats.
Alphabet + numbers = Asahi Factory. Asahi factory = sports vehicle
Number + Alphabet = Ageo Factory. Ageo factory = general vehicle
Custom Order frames, like Grand Velo, custom-made production section in the Ageo factory.
it is the law of A to L = January to December, but if the monthly production exceeds 99,999 units, the alphabet will be moved up. Isn't it?
In the list,
A = January
B = February
C = March
D = April
E = May
F = June
G = July
H = August
X = September * The order is <I>, but it is easy to be confused with 1. Use <X> as a special case.
J = October
K = November
L = December
Below this, if the monthly production exceeds 99,999 units
M = January
N = February
Y = March * Although it is <O> in order, it is easy to confuse it with O (zero), so use <Y> as a special case.
P = April
Q = May
R = June
S = July
T = August
U = 9 Month
V = October
W = November
Z = December * <X> in order, but since <X> and <Y> have already been used, it is speculated
that <Z> will be used in advance .
The above is my own guess, so please be careful not to make a mistake .
For me, this is a more satisfactory description of Bridgestone serial numbers than I have seen anywhere else.
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