There is no time line that I know of but
http://www.43bikes.com/
has a collection of pictures of many De Rosas from the 1970s which is exceptionally useful.
I rather think a very tight time line is almost certainly not possible - different features were probably available at the same time. But there are some clear time points - Campag short ends were probably used from 1976 onwards, cast lugs were used from c1979/80. The diamond shaped chainstays I believe were introduced in the early 1970s - c1973/4?. Frames were built with and without heart cutouts at the same time and there were different types of heart cutout - those with long point lugs and longer cutouts are I think earlier than the shorter lugs with short squat cutouts. There were different types of bottom bracket cutout and drillings too but I suspect these cannot be more than very broadly stuck into a timeline. It has to be remembered that De Rosa's framebuilding shop was really quite small in the 1960s and 1970s so frames were probably only made in small batches at the most and quite likely many would have been one-offs.
It was only with the introduction of the cast lugs and I believe a move to new premises that De Rosa started building larger quantities of frames ... with 1980s and later frames a time line should be possible as the workshop was much more organised. Columbus SLX was introduced around 1984 so frames built with SLX must postdate this - Columbus tubing introductions can be sorted though I think there is no timeline at present for them. Throughout the 1980s the cast lugs pretty much remained the same but certain features such as a concealed rear brake cable and paint schemes will help to date frames - bottom bracket shells also changed over this period and its probably possible to sort out an order for these.
I am sure that others on CR have much more knowledge and experience than I have and can add to what I have outlined.
Hilary Stone, Schiedam, Netherlands
Bruce Audino wrote:
> I was wondering if anyone knows where I might find a De Rosa timeline
> for the Professional model. I am under the impression that they had
> only one road model that they released from the 70's at least through
> the 80's (Professional). I was curious as to time periods when, for
> example, they added or removed the heart-shape cutouts from the fork
> crown, added the Eddy Merckx decal or went from SL to SLX Columbus
> tubing or any other subtle changes. I searched online to no avail.
>
> Thanks, Bruce