# Colson serial number analysis please



## TwoSchwinns (Jan 8, 2013)

Here's the number from my Colson, said to be a '39. It's a double curved bar.





Notice the upside down S A  (under the 7797  E).
Does this serial indicate date and what does the S A mean?

Click on pic to enlarge.

thanks


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## fat tire trader (Jan 8, 2013)

My first guess is that SA are the initials of the framebuilder


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## fat tire trader (Jan 8, 2013)

I have a few Colsons. I'll look at their numbers tomorrow to compare.


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## fatbike (Jan 8, 2013)

Not sure what the  "S A" is, probably shop stamp, who knows . If the "S A" was a Colson provided stamp it would be the same size font as the serial # not smaller. But by looking at your double curve bar, It appears to be very close together. You probably wouldn't be able to fit a tank on the frame. With the info I see I would have to date your Colson as a 1936 and not 39. The stamp date did not start until 1937 so i will rule out it being a 37. 1936 and 1937 double curve and straight bar framed bicycles were identical in design other than the year stamp digits. Your style frame stopped production before 38 and the wider doulble-curve bar started in 1938 to accommodate the new tank design and continued production of that frame until probably 1941. Now the forks and most of the parts were considerably different between those to years talked about 36-37. But the heart chain-ring and cranks were the same for 36-37.


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## TwoSchwinns (Jan 8, 2013)

RMS37  posted this earlier in a different thread.
'Many Colson Serial numbers have been found to follow a pattern where the letter represents the month and the year is represented by the digit next to it. 3106K would probably date the bike as late 36 which makes sense as the earlier 1936 models used a tubular fork.'

Does that mean mine is  May 1937?
By the way, the fork shown in my pic is not a Colson fork. I do however have some waterfall style truss rods and plate that came with it.


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## TwoSchwinns (Jan 8, 2013)

fatbike said:


> You probably wouldn't be able to fit a tank on the frame.




That is correct, a tank won't fit.


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## fatbike (Jan 8, 2013)

"S A" doesn't correspond with Colson that I know of. That is correct with month and year digits Colson dating system starting in 1937 and later. Example " E 7 " May 1937...   I believe yours to be a 36.  Serial numbers that Im familiar with all the Colson bikes I have had and had were like this:   


                                                           *****    Main serial number
                                                             E 7      Letter meaning month and number being the year  "somewhere above or below the main #".


Serial number than the date digit letter and number under or above the serial number, not on the same line as the serial number, not typically the normal. Although I have seen in a few occasions where frames do not even have a date after 1936. I have a 39 original Imperial which ends in a "9" only at the end of the main serial number with no extra digits near it which again is not typical from my experience. But the original paint and deluxe pin stripping, tank and parts characterize it factoring it is a 1939. But again not a typical serial number dating system with Colson after 1936. But agin we are all still learning bikes built at least 70 years ago.




1936 used the later style forged fork but with the earlier truss set up on all fleet model bikes. All current best of the best for their line up with this particular frame style. I'm sure lesser models for that year did use tubular forks from the back stock.


Here is a 36 tall frame and a low end 37 with a stock 36 style fork model Colson but a straight bar version. Might be able to see the fork Im explaining.


Hopefully this makes some sense.


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## TwoSchwinns (Jan 9, 2013)

Let's see if I have this right.
So the bike is a Colson, not a similar style, but the 1936 serials had no connection with a date code, and the SA is still to be determined?


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## fatbike (Jan 9, 2013)

*Correct a Colson. Its a two year style frame. 36-37*

And being a 1936 there is no connection with the date code. SA undetermined as far as I know.







TwoSchwinns said:


> Let's see if I have this right.
> So the bike is a Colson, not a similar style, but the 1936 serials had no connection with a date code, and the SA is still to be determined?


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## TwoSchwinns (Jan 9, 2013)

Thanks for the information, would not have gotten that far myself.


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## Hermanator3 (Jan 9, 2013)

I really appreciate this thread.  I have a Colson built tandem that I have been curious as to it's date.  The odd thing about it is that the front of the frame is like the earlier tandem model & the center is like the later model & the back is unique.  The fenders are the later gothic style. The paint pattern is unlike any I have seen on a Colson.
The serial # is D93796 in a straight line which I guess would make April 1939 the date of manufacture, three months after I was born.  One of these days I hope to post a photo.


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## fatbike (Jan 9, 2013)

Hello Hermanator3

Well, first off for the most part from 1937 and later you will have "example your serial (D93796) plus a letter and a digit to determine the year and month which would probably be under the serial #.                                                                                          (E 7)    may 1937       

Look somewhere around the main serial number example "H 9" July 1939 somewhere around the serial number but not with the main number in most cases. Post some pix of your tandem and me or other members will be able to identify better for you. Colson first introduced their version of a tandem in 1933 with some subtle changes until 1938 where it took on a completely look. Your tandem does sound very unique with a lot of different parts variation.


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## Boris (Jan 10, 2013)

fatbike said:


> Hello Hermanator3
> 
> Well, first off for the most part from 1937 and later you will have "example your serial (D93796) plus a letter and a digit to determine the year and month which would probably be under the serial #.                                                                                          (E 7)    may 1937
> 
> Look somewhere around the main serial number example "H 9" July 1939 somewhere around the serial number but not with the main number in most cases. Post some pix of your tandem and me or other members will be able to identify better for you. Colson first introduced their version of a tandem in 1933 with some subtle changes until 1938 where it took on a completely look. Your tandem does sound very unique with a lot of different parts variation.




Derek-
Since you probably remember better than I, our conversation with Ron regarding Goodyear and Firestone markings in the serial numbers, this might be a good time to explain those as well, since the subject of correct headbadges has come up a few times recently.
Thanks


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## fatbike (Jan 10, 2013)

Yes... Dave, I remember. Firestone and Goodyear F and G letter with the Colson serial number to indicate if the Colson built for either one of those companies mainly took place in 1941, nothing earlier that I know of. And if they are a Goodyear or Firestone it could also have a G or F behind the nameplate. Another topic, it will only confuse this thread.


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## Boris (Jan 10, 2013)

fatbike said:


> Yes... Dave, I remember. Firestone and Goodyear F and G letter with the Colson serial number to indicate if the Colson built for either one of those companies mainly took place in 1941, nothing earlier that I know of. And if they are a Goodyear or Firestone it could also have a G or F behind the nameplate. Another topic, it will only confuse this thread.





Thanks, I knew you'd remember. Although, if these letters appear in the serial number, I do think your information is pertinent and helpful to this thread, if it can help to identify a bike. I'd forgotten about the markings underneath the headbadge.


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## slick (Jan 10, 2013)

This is an awesome thread and i think it should personally be a "sticky" thread since it will help all the Colson owners date there bikes. Fatbike, you are the Colson god. Thanks so much for all your info. I have 7 Colsons. Now i want to go check mine for the years. I know a 2 are 1941's since they are Bullnose bikes but the rest, i'm not sure....


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## Hermanator3 (Jan 11, 2013)

Hi Fatbike.  Thanks for answering my inquiry.  There is no other stamping on the bottom bracket shell but the serial # reported.  Could it be a Colson build for another brand? I still haven't figured out how to post pictures but will post pictures when I do.


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## fatbike (Jan 11, 2013)

I don't think so. Probably a Colson issued bicycle. You can check under the nameplate to see if there is anything. Sometimes there is a name or digit stamping of who or what its intended for but not always. 



Thank you Slick, I definitely do not know all of Colson or all period. My strongest knowledge mainly with Colson is 1936-41.  Just spent a lot of obsessive time researching the ones I have had and having my hands on at some point and really eyeing up details until I got headache.  Also few really good guys to call on Ron Summer, Phil Marshal and Geo. They are a wealth of knowledge with Colson.


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## buickmike (Apr 10, 2020)

Looking at my colson straightbar now  serial number has R following it and below numbers has G 7 stamped . On headline it bears a stamp of W and is sideways at that. Well I'm gonna have to find a badge for it cause it's almost ready for the road. Seen Scott mcaskey E-bay Store with some. Since I loosened truss plate to straighten fork don't know if water fall badge would stay put. Might have to tweak rear wheel a might + bolt up a dropstand.


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## Adamtinkerer (Apr 10, 2020)

buickmike said:


> Looking at my colson straightbar now  serial number has R following it and below numbers has G 7 stamped . On headline it bears a stamp of W and is sideways at that. Well I'm gonna have to find a badge for it cause it's almost ready for the road. Seen Scott mcaskey E-bay Store with some. Since I loosened truss plate to straighten fork don't know if water fall badge would stay put. Might have to tweak rear wheel a might + bolt up a dropstand.



G 7 is July '37


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