I have a 1961 or 62 Italian bike with Columbus tubing that I occasionally ride. I really like the ride, but I find that within my fleet I ride it very little because of the inconvenience of the friction downtube shifters.
I made several upgrades to the bike, some of these upgrades may or may not be practical with a French bike. Upgrades are as follows.
- When I bought the bike used in the late 1970s, it was badly abused. I have repainted the frame twice since then, most recently was a couple years ago.
- In the 1980s, the early 1960s rear derailleur had a major bolt come unthreaded and a piece of the rear dérailleur was lost in the ditch. I installed a new Nuevo Record at that time.
- And the last upgrade from the 1980s was adding some plastic fenders from that era. Other upgrades were in the last couple years.
- Wheels were 120mm rear hub spaced five speed with tubular tires. A couple years ago I got a great price on a used pair of mid 1980s wheels, 126mm rear hub spacing and clincher rims. I tried to cold set the frame to take the wider hub, but the Columbus tubing was like spring steel and I finally gave up. But I use that 126 spaced hub, it just takes more effort to squeeze it into the frame.
- The original crank with Campy 151mm BCD chainrings was 52/48 and I wanted lower gearing. I installed a Campy square taper cartridge bottom bracket and a Campy triple that was 52/42/30 for better gearing.
- The original five speed freewheel was 13/21, I put on a six speed freewheel on it with slightly higher gearing. When using the 30T granny, the rear derailleur will only work with the largest three sprockets on back because the derailleur cage will not take up all the slack.
- I prefer interrupter brake levers. The original handlebars were way too narrow for me and needed updating. I used modern handlebar, modern brake levers, interrupter brake levers, threadless stem, quill to threadless adapter. The reason I went threadless was that wanted the ability to try different reach, meaning different stem lengths without major effort.
- Clipless pedals.
Everything else is stock including the Mafac brakes, but as noted above the brake levers were changed.
I really like the ride of the bike, but because of the friction downtube shifters, I just do not ride it very much. I just like indexed shifters too much.
First photo, the new handlebar setup, second photo is of the bike, third is the reason I do not ride it very much.
I am now retired and have the resources to make any changes I want. I bought this bike when I was still in college, so it has been an on-going on again and off again project over many decades. I worked in a bike shop before college, so I have done all of my own work on the bike.
The reason I am going through this long list of changes that I made is that you might find that updating an older bike can take a lot of effort and in the end, you do not know if you will still want to use it as much as you would use a modern bike.
And as a hobby, I enjoyed working on the bike but I do not know if that would be the same situation for you.