Ateliers de la Rive, the producers of Vitus 172 made plain "Vitus" tubing from at least the 1940s through the 1960s.
I have no idea of the chemical composition or tubing wall thickness of the original "Vitus" tubing but it was considered at least equal to Reynolds 531 back then.
Here's the specs for Vitus 172 from a 1974 publication:
1.1/0.75mm Wall Thickness 3 Main Tubes 1.0mm Wall Thickness Chain Stays & Seat Stays 1.2mm Wall Thickness Fork Blades
Vitus 172 from that era was made of seamed tubing except for the fork blades which were the same tubes as used on the lighter Super Vitus 971 tubing.
The 3 main tubes were drawn over mandrels to generate the butted ends which also eliminated any potential problems from the seams.
The steel used in Vitus 172 tubes had a Tensile Strength of 120 ksi and a Yield Strength of 106 ksi which was just slightly lower than Reynolds 531, Columbus and 4130 Chrome-Moly tubing.
It was probably a low alloy, high strength steel made with a closely controlled heat treating process to get the high strength.
About 1976 or 77??? Ateliers de la Rive produced a flyer with wall thickness specs for their Super Vitus 971, Vitus 172 and Durifort-Rubis tubing.
http://www.yellowjersey.org/
They lightened the Vitus 172 tubing a little from the 1974 dimensions, here's the newer specs:
1.0/0.7mm Wall Thickness 3 Main Tubes 0.9mm Wall Thickness Chain Stays 0.8mm Wall Thickness Seat Stays 1.2mm Wall Thickness Fork Blades
This put Vitus 172 in the same wall thickness range as the standard 1.0/0.7mm Reynolds 531 tubing and Columbus SP tubes.
After the late 1970s Ateliers de la Rive began continually changing the specs and alloys used in their tubing.
Every Vitus 172 frame I've ever seen had the forks and stays as well as the main tubes made of that tubing.
I have 2 bikes with Vitus 172 frames, a 1980 Motobecane Grand Jubile and a 1979 Bertin C132 Cyclotouriste. They ride the same as a frame made of standard Reynolds 531 1.0/0.7mm or Columbus SP tubing.
Chas. Colerich Oakland, CA USA
Peter Rogers wrote:
> Dear All,
> Just wondering if any tubing specialists on the list can answer some questions about Vitus 172 tubing.
> Here they are:
>
> Was the Vitus 172 series a good tube set?
> Was it available in double-butted and plain gauge?
> Is it seamless?
>
> I have a mid/low end Mercier "Service des Courses" frame that has a sticker stating that it is made from 172 SERIE LEGERE. Unlike other Vitus 172 stickers that I have seen, it does not specifically state that it is double butted tubing.
>
> Any thoughts?
>
> As always, your help will be very much appreciated.
>
> Kind regards,
> Peter Rogers
> Barrie, Ontario, Canada