I spent about 8 months reading about vintage bike, i learn a few things, but i still clueless about this frame l bought.

What pictures should i take and information will be helpfull in order to help identifying it ?

thanks in advance
=)

Certainly a head badge if there is one. After that details of lug work, especially the seat lug area since that's where verious builders do some of their most characteristic work.

Also good photos of the fork, especially the crown, and lastly the dropouts because builders use various styles when attaching them.

And a picture of the whole frame (or bike) please, so we can see the geometry.

Bring on the pics!

Thanks a lot for your replies...
If you need more photos i can take it....
the bottom bracket is 40mm, i read its named thompson bottom bracket, i can measure the tubes diameters if it would help as well ...











thanks a lot !!!
=)

70's French to start it off.

Thanks for the pictures. I have no idea what I'm looking at, but I certainly would like to know. Some observations:

- Simplex drop-outs, nicely brazed
- cheap-looking fork crown
- seat stay tops I've never seen before
- head tube lugs look paper-thin - are they lugs at all?
- tacked-on cable guides - mostly seen on French and Belgian bikes

I think we should call Detective Chief Inspector @juvela ...

the guy who sold me this frame at the time was selling some MAFAC brakes.


The two things that grabbed my attention were the head tube lugs and the seat stay tops, I may have looked one million bike pictures on the Internet trying to find seat stays like that ... without any success...

It looks like your bottom head set bearing cage is upside down. Too much space between the cup and race.

Back to the frame ID.

well, my goodness we certainly have an oddity here...

the bicycle's thompson bottom bracket assembly is sometimes referred to as a thompson-simplex (no, not the juy one ). the frame's bottom bracket shell is agrati nr. 000.8507 and will likely be threaded italian, even though the threads are not used in the thompson system. a traditional three-piece bottom bracket assembly could be mounted straightaway.

the frame's head is bulge-formed and made by agrati; it is item nr. "EXPORT" with angles of 72 & 63 degrees. length/height is likely 140mm. the seat lug looks to be the agrati nr. 086.8569.

my guess is that we are in one of the germanic countries of western europe here. if i had to go out on a limb and guess a specific nation i would say germany. no ideas as to manufacturer.

IMO it's a low-mid level generic French bike. It's hard to tell from the photo, but I believe that a close inspection will show that the head tube is a single piece simulating a tube with 2 brazed lugs. Instead it's a single piece embossed to look that way. These were common on low end bikes that wanted to pass for better.

Thanks for mentioning... l'm not the best guy to assemble a bike... LOL.... i will set this up




Thanks a lot ! it`s a lot of info ! do you have a catalogue to get the information ? because a googled agrati and there int's much about it on the internet...



thank you, I was expecting to be something middle leveled, due to the lack of references on it... I bought it as a chrome-molybdenum, is there a way to make sure it is cr-mo or not ?

Hello Lalas,

with respect to suggestions of frenchness - have a look at the spotwelds. they are square, france does round ones, germany square. note also the attachment of the upper end of the frame's seat stays to the seat lug. this is done by a staking technique widely employed by cycle factories in germany and austria but not used in france.

easy measurements you can make -

tube diameters: top tube will be 25.4mm, steerer will be 25.4mm, down and seat tubes will be 28.6mm.

shell width: if 70mm it will be italian threaded 36X24f, if 68mm will be bsc/iso threaded.

cycle may have been produced by one of the large german makers. they do a good deal of private labeling so even if we were to learn the factory we may not know how bicycle originally badged.

since it is a respray there is always the possibility that some transfer vestiges may remain beneath the paint finish...

yes, i have an agrati print catalogue.

The head tube construction is more indicative of a lower than mid range frame. If I'm right, I doubt the tubing is Cr-Mo, and is more likely a 1010 or 1020 carbon steel which would have been par in those days.

You can confirm or disprove my theory about the one piece head tube bu comparing the thickness of the lugs at the top an down tubes vs. against the head tube. Lugs would be the same, roughly 1/16" thickness all over, usually with a pronounced step where they end.

As far as knowing for sure, the only way would be to remove a small sample of the metal and send it to a metalurgist for chemical analysis.

one simple check that can be made to give some indication of tubing quality the diameter of the bicycle's seat post. for conventionally constructed adult steel frames the typical range here is 25.0mm to 27.2mm. in general, the larger the seat post size the better the quality of the tubing (somewhat of an oversimplification).

here is a directory which gives some information about the sizes:

Sheldon Brown's Seatpost Size Database

to see other bicycles with your type of seat stay treatment you can check google images for the brands kalkhoff and victoria.

here is a forum thread on a bianchi bicycle constructed with the same agrati bulge-formed head as is seen on your frame. scroll down to message nr. four to see a closeup picture:

https://www.bikeforums.net/classic-vi...lp-please.html

best wishes with your investigations!

FBinNY

I though there was a simpler way to check if it's cr-mo, I believe in what you say, when l wrote i thought it was cr-mo, I meant that I pay for something and got another thing, you opinion and knowledge counts more than the seller's ... he tricked me....

juvela

Thanks a lot Juvela, now I have some direction to move !

To be clear -- I'm not saying it isn't CrMo. Just that if it has a one piece head tube assembly that would argue against it. As I said, the only way to know the specific alloy would be chemical analysis. Jut as you can't tell by look and feel, I certainly can't tell from a photo.

Hello again Lalas,

came across this bicycle whose frame demonstrates some similarities to yours. it is constructed with an agrati bulge-formed head series "EXPORT" of a pattern slightly different than than the one employed on your machine. it uses the same fork crown, agrati seat lug and seat stay attachment as seen on your cycle. likely dates from the 1971-72 time.

you might discover a model and year for your bicycle if you search this name. perhaps you could find a back catalogue or two to advance the process...



Amazing GERMAN1960 1970's Kalkhoff Super Sport 10 Speed Racer Bike Like Schwinn | eBay