Welcome to 2026 and the sensational new Series "Enigma Italiano",

Where you try to guess who built this "mystery" frame.
Questian (1) Is it Italian ?
Questian (2) How old is it?
Questian (3) Who built it?

Here are some clues

Frame is 52 cm (seat post top/ center)
Inner diameter of seatpost is 27mm
fork ends and dropouts - Campi
Headset - Campi
Seat binder bolt - Campi
brakes - Universal super 68
Frame weight (incl drive side bb cup 4.1 lb
fork weight 1.62 lb
( frame came with suntour derailleurs and down tube shifters, Sugino cranks and bb, lyotard pedals, probably all retro fits, Frame looks like it's been powder coated)

And now some pictures:











The first person with the correct answer will receive a mention in my next "Bike of the Month" article.

details look more "Brit" than typical Italian: such as the Campy vertical DOs, the fastback seat cluster, the forkcrown...headlugs are quite unusual in the bottom sockets, but the '3-hole drilling" is not so exclusive, but again more typical for a few Brits (maybe some Yanks, too) rather than any Italians that jump to mind.
Did Sugino offer BBs with Italian threading?

If i had to make a WAG it would be some slightly more obscure make like MKM, I sure don't recognize that mark on the BB shell, but again seems like something from a smaller-output builder.

Yes, Sugino made Italian bottom brackets.
Phil

What is the BB thread? It's easy to tell if it's Italian by trying an Italian cup. If it seems even in the ballpark for threading in, then it's Italian. French, English and Swiss are a full mm smaller, so there's no mistaking the fact they won't begin to fit. Conversely if you check it with say an Eng cup, it will fall in without the threads touching.

I agree the frame is unlikely to be an Italian make, what with the French-made (Prugnat) fork crown. Back then it was rare for an Ital builder to use French frame parts. Even if the BB thread is Ital, I'd still be skeptical. That'd make me think USA, since a few US builders used Ital BBs.

Yes those dropouts are Italian-made but almost no Ital builders used them.

Yes Cinelli used seatstays that attached with the seatpost pinchbolt integrated into the stay tops, but not like how it's done here. The cylindrical boss with the stays mitered to it is mostly Eng. or US. Never seen an Italian do that, counterexamples please if you know of any.

It's an intrguing frame, whatever it is. Keep us posted if you find more info on it.

Italian builders that used fastback stays brazed to the pinchbolt include (later) Pogliaghi's and Freschi (who worked at Pogliaghi). But yes, it is uncommon for an Italian frame to have them.

That frame looks like late 1960's to 1970's English or American, maybe South American ? Maybe Belgian or Dutch ?. Some of the details look somewhat amateurish to my eye.
Those Campy "vertical " dropouts were crude in design, and they weren't "vertical". Most every frame I've ever seen with them has them positioned so the rear wheel has a harder time trying to be removed or installed.

It might be a home-made frame by an Amateur or a Machinist ?

The "M" cut-out in the BB shell is the only detail that makes the frame look like it might be built by an actual Framebuilder. Except that a machinist would have pretty easily been able to do that.

No braze-ons at all also makes me scratch my head.

I am going to say French Alain Michel.

we need to know the tubing diameter and the bb threading

To my not-even-close-to-qualified eyes, the frame looks British or French.

If it's Italian, I'm going to guess that it was built by that legendary framebuilder, Hooda Hellanosa.

--Shannon

This is possible. The seatstay bolt style and the three circle drill outs on the lugs are seen on some AMs, but my recollection of the Alain Michel “M” was that it was a play on the Arc de Triomphe rather than a stark, Capitol “M”. The Arc de Triomphe was used on the fork crowns, too, which I don’t see here since we didn’t get a shot of the top of the fork crowns.

Yes^ true there are a couple details that might point to Michel, but here's what his "typical" headlugs and "M" mark look like (in this case on the forkcrown) so not convincing evidence there IMO:

Pretty bike!

--Shannon

more detail

top tube 25mm

down tube 27mm

seat tube 27mm

bb serial no. GBH 0013

bb threads 37 x 24mm

Could this be associated with Garda Bike Hotel?
Phil

all this seems inaccurate:
if the tubes are METRIC then the dimms should be even number mms: 26 and 28, if they are Imperial then fractional mms 25.4 and 28.6 (= to one inch and 1/1/8 inch)
and that theading spec is either Italian which SHOULD be 36mmx24tpi OR it's BSC/BSA/ISO in which case it's 1.37" x 24tpi

say what?

I should have added that at this point if the BB threading was some typo then it's very unlikely that we have either a French or a Swiss BB shell, so that might kick away any chance that this was made by Alain Michel.
We need better clues (or none at all)

i spot an "M" intertwined with a "Y" in the BB, if that is a hint for anyone

Apparently many Alain Michel bikes have Italian threaded BB. I still wonder if it is an early model before the "Arc de Triomphe" logo was developed.

I did not know that, do you know what tubing AM used and if he built with metric tubesets?

Whoever the builder turns out to be I keep thinking the treatment shown on the bottom sockets of the headlugs seems something very distinctive, plus maybe a little "Gallic/Construteur" if i was to put a label on it

plus the fork blades have a certain "Frenciness" to the bend...

I have a friend who owns one and I will contact him for some info.

O/k. Let me do this another way.
the bottom bracket cups are Sugino 1.37 x 24tpi
using a good metric caliper this time
top tube 25.2 down tube 28.9 seat tupe 28.9MM (including paint)

or inches
top 1.08"
Down 1.140" seat 1.35"

so British?

I wouldn't be so quick to say British just from the tubes being inch-based dimensions and Eng./ISO BB threads. Lots of bikes from other parts of the world used those too. Almost everywhere other than Italy and France.

Your revised numbers still contain some typos, I believe at least three, can you doublecheck?
25.2 mm is under 1", not 1.08".
You got 28.9 mm for both DT and ST but got different inch conversions?
Your ST is not likely to be 1.35", that's over 34 mm.

Okay, I heard back from my friend and his Alain Michel has an English bottom bracket! Apparently Alain Michel built bikes with both Italian and English bottom brackets. He has sent the frame off for paint so is unable to measure the tubes.

Sorry if my measurements are not what is expected. I used a Mitsutoyu caliper that has both inch and metric scales but is analog and reading the scales in metric accurately is difficult. Perhaps if I had a digital readout it would be more accurate.

Thanks for all the feedback anyway. For now I will assume it is a British made frame from the late 60's or early 70's. Unless it is something very special no one besides me will probably care who made it. It will be repainted and sold by the bike exchange, probably for a couple hundred bucks and someone will get a very nice very light bike that they can enjoy.

Any chance this is Belgian or Dutch? They would often use BSA threading but Italian-esque frame details?