Is there a reference here or in the archives to time periods/dates for general features on high-end Italian-made bikes?

I'm essentially trying to date a frame that has some features like a clamp-on front derailer, over-the-bb cable routing and no serial # (doesn't look scratched out or repainted, just not there at all.)

Is there a consensus here about when, for example, cable routing changed or braze-on's were used or is that just a crap-shoot depending on way to many variables to accurately pin down any general ideas about when a frame was made?

This is probably WAY to general but what the hell...I'm stuck!

Lots of variables but most high end Italian frames used no braze-ons until the early-mid 70's.

I've been told the Campy braze-on cable guide for the BB shell was introduced around '72, but many builders continued to use clamp-on's.

I think shifter boss braze-on's were not real popular until about '74, and top-tube cable braze-on's although available through the mid 70's did not seem to become really standard until about '78-'79.

Front derailleur tabs would be more like a post '83 thing for most of the big builders.

Brakes went from nutted to recess style around 1980 or so.

Of course that is all very general and does not account for all the small custom builders and special orders.

A related question I've been pondering is: When did the high-end builders switch from single, down tube water bottle bosses to adding a second set on the seat tube?

stan

beginning approx 1981/82

i'm also thinking that the switch to recessed brake bolts was more like 77/78
btm bkt cable routing from above to below was a gradual shift,depending on the builder's preference beginning around 78 but was not widespead practice until around 1980/81

So if I've got a frame with:

1) Clamp on front deralier
2) Over the BB cable routing
3) No seat tube Braze-on's (only on the down tube)
4) Brake cable routing on top of top tube

I've probably got a very late 70's/early 80's frame -

That sound about right?

The braze on Bottom bracket shift cable guides by Campagnolo were in limited use but production in 1970. I do not have my Campagnolo catalogs nearby, but they might have been listed as early as 1968. You are correct that changes like this were slow to be adopted. Back then, it was the trade shows where items were presented to the public and other builders where the cross pollenating would happen.

Earliest recessed brake mounting I have seen was 1976. But back then it was RARE.

The short path here would be to simply post good photos.

Interesting. Other variables include rear derailleur cable over or under chainstay, clamp on or brazed stop for the same, clamp on or brazed water bottle bosses, internal rear brake cable routing (over or under top tube entry), etc.

I just checked my circa '76 De Rosa, and it has the pre-CPSC flat QR handled brakes with allen key mounting.
I think that dating on the BB cable guides is about right - definitely pre-70, but not by much. I didn't see them in the '67 catalog but I seem to recall they're in the one from '69.