i just found this half rotten bike in the backyard now trying to find out its story. A little help to identify brand, model and age would be much appreciated.

Here are some facts:

- the only sticker on the frame says: reynolds 531
- the bottom bracket has two cutouts and carries a two digit number (57)
- the fork has an "S" on both sides of the crown (Mauro Sannino?!)
- Cinelli stem with 3t bar "mod competizione"
- most parts are shimano600 so i think its from the early 80s

pics attached (please let me know if you need to see more details)

Thanks

It was a nice bike. 57 prob'ly means size frame. Tubular tires could indicate a high end. Fork might be original or replacement, don't know yet.

seatpost 27.2 ? Would like to know threading. Seems to be mish mash of parts.

no guess yet.

that "531" decal is very strange: it's an enlarged version of what would normally go on 531 FORK blades, so that's a red herring. We have seen a similar "S" engraving on fork crown as this one, but it's been so long I can't recall what the brand ever turned out to be (IF it ever got IDed, that is) I don't think it was a Sannino but it's one worth investigating.The "strap" guide on the BB shell is similar to a style that early Pinarellos employed, but I don't think that's a possibility, however most of the details look "Italian".
Yes: seatpost size and threading of the BB are the next clues we need.

yes, seatpost is 27.2
I dont know much about tires, but i did cut off the old ones just with scissors. so there was no metal in it.
the rimtape was more like a mullbinde and partly came off with the tire.

thanks for the quick replies and interesting guesses, i'll check on the bb threading tomorrow, don't have the tools around atm.

what you had were "sewups" AKA tubulars, tubbies and sprints and the tires are glued onto the rim (or nowadays you can use Tufo double-stick tape instead of glue).
Are we seeing a crimp in the backside of the seat-tube to allow for tight rear tire clearance?
For some reason I think the old example with a similar forkcrown "S" was once ID'd as an Austrian brand "Simplon", but I also think that ID was shot down and a different positive ID was eventually made, but I would have to do a deep search of archives to find the old thread...
Look into the base of the fork's steerer and see if there are 5 shallow spiraling ridges in the metal...cause I'm guessing this might be Columbus SL tubing and not Reynolds 531.
Any markings on the dropouts or forkends such as: Campagnolo or Gipiemme or Columbus?

I guess you mean i need to open the bb, right? Here some quick pics of it

if you can get the drive side (RH side) crank off there's a good chance of something stamped on the edge or face of that "cup" but also looks like a Shimano BB so you might have to remove the BB unit to read any info off a label on the main body...do you have the special tools for all this? If not maybe a friend or friendly bike shop is the next stop...you can't do these jobs with common household tools I'm afraid, especially if you encounter RUST and CORROSION (which I bet you will).

EDIT: Just looked at some Sannino frames and all seem to use a distinctive stay cap (sort of like Gios but not exactly) and nothing like the OP's...plus the "S" on the forkcrown is also very different, so very doubtful it's a Sannino.

I'd say this is a Simonato (or at least the fork is)







You can check out these two threads for more pictures. The blue frame in one of them has the same seat tube crimp and chainstay bridge:

Identification cadre Simonato | Forum Velo Retro Course

Forum Tonton Vélo ? Afficher le sujet - Oscar Simonato

^I think we have a WINNER!^ and a Treviso-based builder, too, so in the Pinarello neighborhood! excellent detective work MauriceMoss!

BTW, we had this old thread in C&V with another forkcrown "S" just like the OP's:
https://www.bikeforums.net/classic-vi...o-special.html

Wow, thank you all very much!

Could take some month, but i'll keep you posted on the rebuilding process.

@unworthy1: there is only one straight ridge, top to bottom inside the steering tube. [MENTION=383399]MauriceMoss[/MENTION]: Awesome find, thanks for the links!

that's a bit of a surprise since I'd expect that an Italian frame with a 27.2 seat post would be all Columbus SL and so would include the SL steerer (which has 5 spiral ridges inside the base)...BUT there were many frames that either were "tre-tubi" meaning just the 3 main tubes are SL and also many that substituted lower cost tubes such as Falck to save a few Lira in the materials cost. However, the steerer is probably the lowest cost tube in the set so the savings would be minimal, hardly worth it. BUT another angle is that this is made of Oria tubing and since there's that Treviso connection it's another strong possibility: Pinarello was a big user of Oria tubes.