What is this mystery threaded hole for?
 

Thanks to all your help on a number of threads trying deal with the idiosyncrasies of this bike (best estimate is 1989 Colnago Super Piu), I finally got my bike built though I still have to fix the seatpost and saddle angle after they slipped on my shake-down ride.
https://cimg1.ibsrv.net/gimg/bikefor...41da3949ac.jpg

One thing that puzzles me though, is a threaded hole immediately in front of the race number hanger. Does anyone have any idea what it would be for? Some sort of removeable pump peg?
https://cimg6.ibsrv.net/gimg/bikefor...7388230423.jpg
https://cimg5.ibsrv.net/gimg/bikefor...cf3d630432.jpg

Two-bolt number hanger?

@himespau

Maybe, but it seems the no. hanger would be in the way no matter what and this would be well into the frame fit era I think.

Also seems like it would be very difficult to orient the peg and get it tight enough to stay put.

In other words, I really have no idea. ;)

Maybe if your race number is a different size you move the little chrome dealy out to the other boss?

Or it could be an adventure nipple ahead of its time. Modern "gravel" bikes are usually covered in a rash of bottle bosses at funny spacings with no apparent purpose.

Yeah, the only way I was thinking it would be would be the long L-shaped ones and would be mutually exclusive with having a race number on there. That was my only guess and I knew it wasn't a very good one.

Maybe they let the apprentice do that brazeon and he managed to get it in the wrong place, so a second was added. A total WAG.

Good thought but the number hanger is a brazed on loop sticking out of the frame. The chrome dealie is threaded into it to sort of clamp the race number in place.

Ooh, I just figured it out. It's the ultimate in luxury frame mods. Just like some frames of that era (but unfortunately not this one) had little brazed on attachements to hang the chain when you'd taken the wheel off, this screw hole is a place to stick the screw for the number hanger so that you don't lose it when you're taking it out of the number hanger to mount the number. Actually, probably not, I have no idea what it could be.

To be fair, the FD braze on is very low (I went through 4-5 FDs before finding one that would clear a 53T chainring and, and even that one would only do it if it was rotated so far it wouldn't work. I think I was on try 7 before I found one that would actually fit and shift properly. Also, the crown race seat was 26.7 rather than 26.4 and no one had bothered to mill it down, so I wouldn't be entirely surprised if this frame was built on a friday after a 3 beer lunch in Italy.

It is a lightening hole, to reduce weight.

I think they eat and drink right in the factory. My Arabesque shipped from Italy with a hunk of bread in the BB.

https://cimg8.ibsrv.net/gimg/bikefor...6ced2b3f65.jpg

Fancy drillium

Big frame……..might be for mounting a frame-pump support bracket beneath the top tube. Just a WAG.

How’d that bread make it past customs?! Sounds like I’ve got some, ehm, lucrative business opportunities brewing in Italian bike shipments. :rolleyes:

Honestly, since this is one of the years where both entrances to the internal routing for the rear brake are on the top of the top tube, if you'd told me that it was a drainage hole that they put a threaded collar on so that the edges wouldn't be stress risers, I would almost believe you. Almost, except for the fact that the internal cable routing is a complete tube within the top tube. Which reminds me, when I frame-savered the frame, I didn't spray any in those holes. Oh well, maybe next time.

Speed hole

Braze on for the turbo charger/engine.

Mounting holes for schrader adapters, one for each wheel.

I hear that there are several other subforums where this would have been better posted, but there's no denying that this is an interesting bit of information about schrader adapters.

No idea on the threaded hole but my guess is the bread was put there on purpose to soak up humidity. Works great for brown sugar.

Put a D-ring bolt in it, and when you're riding with your mates just reach down and adjust it and accelerate at the same time, they'll all be like, whaaaaaat?

Done Michael Peña style!

Or is it Napoleon Dynamite?

Bread as a low tech silica gel pod. I love it. Don't need to be as worried if the cats find/eat it.

Just need to find a way to attach a downtube shifter there. T'hat'd work great and confuse everyone pre-ride as much as I'm confused by it now.

I really like the bike anyway!

Back in the late 80's I remember putting some under the top tube water bottle bosses to hold a short Blackburn pump that had a holder designed for those under the top tube bosses. I don't think Blackburn made that holder for long. They went to holders that could fit on the side of a water bottle cage but was held in place by its bosses..