While working on issue 4 of Vintage Bicycle Quarterly, dedicated to the famous technical trials, I came across a few interesting facts.
Not only were the trials rigorously administered, so there is no doubt about the light weights - you will see the results sheets in VBQ 4 and 5.
Also, in one event, Lionel Brans (a constructeur) entered a machine built with a Caminargent frame. To Americans, this may seem puzzling - how can Brans be the constructeur when Caminargent built the frame? Clearly, the French cyclotourists considered the person who put the bike together, who made sure fenders, lights, racks, derailleurs and all worked together, the constructeur. For them, the frame is only one part of the bike, maybe more important than fenders, wheels or other parts, but not by that much. In fact, it was common among some smaller builders to buy a raw frame, add braze-ons, paint and decals, build the bike, and sell it under their name.
I have felt similarly about my Rivendell. While Rivendell provided the raw frame to my specs, the finished product (shown in VBQ 3) is very different from anything you can buy from Walnut Creek. When people ask me what I ride, I am reluctant to say "A Rivendell," because I don't want Grant et al. to get in trouble because somebody wants to order a bike with different clearances from standard, with a custom front rack, custom handle-bar bag QR, aluminum fenders, custom light mounts, etc.
Of course, most of the well-known constructeurs made frame and bike, so that distinction does not apply. But it becomes apparent that the constructeur is NOT a framebuilder as we understand it.
And finally, how did those bikes get so light? First of all, many of the older components were/are amazingly light. Second, a lot of drilling, and more importantly cutting.
Which gets me to my question: How much is saved by drilling out parts? Somebody must have before/after weights, or be able to compare drilled vs. undrilled parts.
I suspect the savings are small - Ernest Csuka once told me how they spent an hour to drill out a chainring, and then weighed it. They had saved 2 or 3 grams. I think to really save material, one had to cut away whole sections. How about pedals with the center sections cut away, so that the spindle is exposed? Or headsets with exposed balls. You'll see those in VBQ 5 (in fact, it's vol. 2, No. 1), part 2 of the technical trials.
What is the point, you may ask? And you are right. The point was not to make superlight bikes, and many critics at the time were quite scathing about constructeurs "who exploited the rule book." The point was to make lightweight bikes (a good randonneur went from 33 lbs. in 1933 to 24 lbs. in 1936) that held up for hundreds of miles on the worst roads imaginable. Bikes that carried a load and handled well on mountain roads. Bikes that resemble the wonderful randonneur bikes built in France from 1946 onwards. And that goal was achieved.
Shameless plug: Read all about it in Vintage Bicycle Quarterly. Info
Jan Heine, Seattle