Hello, I have this frame and judging by the lugs, it's a Claud Butler but I can't find the model since the fork has a huge rake and the seatstay end has an odd shape. The frame was modified by a previous owner to be a fixie so the cable guides are missing. I think there was a cable pass over the bottom bracket (swiss threaded) and it could've had a derailleur hanger. I used this frame as a fixie for half a year.
The fork threads are english and the rear wheel spacing is for 5 cogs cassette. I think it was for 650 wheels since it requires long reach calipers for 622 wheels.

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If CB it is certainly late enough to be from the Holdsworthy period.

Lugset appears to be Prugnat 62/S, crown Vagner PC.

Shell appears to be Gargatte (Raccords Gargatte Freres).

You mention the BB swiss threaded. This would be more consistent with a cycle from France or Switzerland. Seat stay treatment consistent with a French product. One easy check would be to measure the diameter of the main frame tubes to see if they are BSC or metric. You mention steerer BSC. If frame tubes metric diameter it would tell us fork a replacement. Holdsworthy did employ a lot of Prugnat lugs however.

Have you been able to find any serial markings?

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The BB shell has no serial marking. The worst is that I got the frame with no decals on it so I can't even know for sure if it's a Claud Butler. The current paintjob was done by a friend because the frame really needed one when I received it.

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Was there anything other than lug pattern to make you think it CB?

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If the BB is Swiss thread, it's not a Claud Butler, nor any English maker.

The seat stay end cap treatment looks French to me.

Nothin except the lugs made me think it's a CB. The swiss threaded bb and the seatstays only complicated things.

I found that Bertin cycles used this type of chainstay but I can't find any models to perfectly match my frame.

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As rhm so articulately states a CH shell and a UK origin and mutally incompatible.

If it really is CH then country of origin could only be FR or CH.

If it were CB it could not be CH threaded.

When will you be able to measure tube diameters?

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Downtube and seattube are 28 mm in diameter. Top tube is 26 mm

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Bingo, ladies unt yentlemens ve haff ein metric tubeset!

Zo, eef steerer really 25.4mm eetsa replace-a-mente.

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What? I cannot measure the steerer tube diameter because the frame is in small size and the lugs are too close together but it's fork a 1" fork.

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yes, the "1" fork" is the part which does not fit in.

with a CH shell and a metric tubeset we would expect a steerer diameter of 25.0mm.

so there are two possibilites:

a) the measurement is incorrect, possibly due to a miscommunication

[suspect we are not communicating well. another name for the steerer sometimes used is "fork tube." since you were able to measure the diameter of the main frame tubes you could use the same tool to measure the diameter of the steerer/fork tube. we would expect it to measure 25.0mm. if there is presently a headset in place all that is needed is to remove the headset locknut in order to make a measurement. do you have a seatpost for the bicycle? what is its diameter? this dimension will give a clue as to the tubing employed to construct the frame. if you do not have a seatpost for the bicycle you could use your measurement tool to make a measurement of the seat tube opening.]

or

b) the fork is a replacement

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for a manufacturer identification we need to hear from luminaries on frankish matters such as [MENTION=43980]CV-6[/MENTION] & [MENTION=359579]Filochard[/MENTION]...or else [MENTION=383399]MauriceMoss[/MENTION] who seems positively unstumpable.


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I am confused by this statement. Did you mean the seat stay caps, the top of the stay by the seat tube and top tube junction? Because domed ends on a chain stay are common.

The measures were indeed correct. The seatpost I used was 1" in diameter, so 25.4 mm. I managed to measure the head tube diameter and it is 32.5. The fork steerer tube diameter is 25.0 mm.
This is weird because I once replaced the fork with a 1" steerer carbon fork and it was compatible and free of any problems, obviously I used another headset for the carbon forks.

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Thanks very much for this additional information.

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Did you manage to find something?

It's actually not weird, because English/French/Swiss/Italian bikes, despite the vagaries of tube sizes and threading, all use the same "frame cup inside seat" dimension: 30.2 mm. So any headset that provides frame cups to fit that dimension, no matter what its top cup/nut threading or fork crown race dimension, will fit the frame (theoretically; in practice, as with most interference fits, there are sometimes "adjustments" such as peening the fork crown race seat that have to be made).
https://www.sheldonbrown.com/cribsheet-headsets.html

The OP mentioned that the fork was English threaded, yet the steerer tube measures 25.0 mm. As Charles Wahl notes, the frame cup inside seat is pretty much universal.

I will share that if you are willing to live with a class B or C fit, you CAN run something other than a French metric headset on a French 25.0 steerer tube. My Allegro came to me with a Campagnolo 25.4 x 24 Italian threaded headset that a previous owner had fitted to the Nervor 25.0 x 1 steerer. It almost worked, though it was predictably a teensy bit loose, and he'd left out stuff like washers and a centerpull hanger to get something that needed 42 or so mm stack height to fit onto a steerer cut for a 33 mm-ish headset. I wound up replacing it with the bottom half of a generic Tange headset to fit the monkeyed-with fork crown set and the top half of a generic Motobecane headset that has about the same dimensions as a Stronglight P-3. It works much better, and I was able to carefully thread the French bits back on and have had no issues with it. Measuring stuff with good calipers makes life a lot easier.

All of that said - I think you have some sort of French bike with a Swiss threaded bottom bracket that someone has force-fitted with an English headset. Juvela mentioned Prugnat 62/S lugs with a Vagner PC fork crown and a BB shell by Gargatte (Raccords Gargatte Freres, to which I would add that the dropouts look to me like Nervex stamped units just like the ones on a zillion entry and mid-line French bikes, including this Liberia. All of this is very French. Bertin has been mentioned - did they ever use Swiss threads? I bet other makers used similar seatstay top treatments. Is that swaged and crimped?

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WRT dropouts -

assumed also they would be a NERVEX pattern but could not find them illustrated in me NERVEX catalogue.

there are other makers of stamped ends in France.

slightly surprised to read of the 25.4mm pillar size. frame certainly looks nice enough that would have expected something such as Durifort tubing.

look forward to the observations of [MENTION=359579]Filochard[/MENTION] and/or [MENTION=383399]MauriceMoss[/MENTION]

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Oh, I stump easily! Especially when it comes to locating certain tools. They usually appear after I buy a replacement...

As for the frame here, it's a veritable stumpenade! I've seen that style of stamped dropouts before, on some mid-late 70s Euro market Gitanes and Fonlupt, but then the lugs don't match at all...






Not entirely sure what this one is. I'll keep looking.

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Fine job Nate998!

For you have stumped Maurice!!!

Never seen that before.

At least now I don't feel so bad about not being able to suggest any possibilities...

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Could it be a homemade frame?

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This is a reasonable question.

Find it doubtful as an amateur/homebuilt frame would likely be constructed with forged ends and there would be signs in the metal indicating to the eye a first time builder.


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Asking what may be a stupid question, but here goes - in the interest of possibly advancing the identification process. How was the seatpost diameter measured?

[MENTION=19743]USAZorro[/MENTION] I used calipers