Only the 3 main tubes on Motobecane Grand Jubile frames built between 1973 and 1976 were butted Reynolds 531 tubing. They had Reynolds stickers that said: "3 TUBES RENORCES". The balance of the tubes were made of seamed Motobecane steel tubing, what ever that was???

Pre-1974 and post 1974 French Reynolds 531 3 tubes stickers:



The 1977 through at least 1982 Grand Jubile frames were made with all Vitus 172 tubing. I haven't seen a 1983 Moto catalog but the 1984 shows the Grand Jubile frames were "Inexternal" lugless Columbus "CR-MO" tubing. Probably straight gage Gara or maybe Chromor with butted main tubes.

Vitus 172 was decent French made tubing made of high strength low alloy steel. It was seamed but the 3 main tubes were drawn and butted which removed any supposed weaknesses. The tensile strength of steel was only about 5% or so lower than Reynolds 531 or "Cyclex" the name Columbus gave to their 4130 Chrome Molybdenum steel used in SL, SLX, SP, SPX, TSX and so on. Because of the lower alloy steel, it was also easier for less skilled workers to braze without fear of overheating.

Some styles of Vitus 172 stickers were more fragile than Reynolds stickers.... Both brands didn't do much about having robust stickers made back in the 70's!




In the early 70's Vitus 172 had 1.1mm x 0.75mm butted main tubes. These seat tubes used a 26.2mm seatpost. Vitus 172 from the mid 70's on with the 1.0mm x 0.7mm main tubes took 26.4mm seatposts.

This later version Vitus 172 was the tubing Motobecane used for the 3 main tubes of the 1976 and later Grand Touring Frames. In 1977 the Grand Jubile frames changed from Reynold 531 3 main tubes to all Vitus 172 tubing. The Grand Record frames changed from all Reynolds 531 to all Vitus 172 in 1979.

The wall thickness of Vitus 172 was about the same as the Reynolds 531 "Sprint" tube sets used on a large percentage of European production frames. The Main tubes were 1.0mm thick in the butted ends and the unbutted sections were 0.7mm thick. Only the top and down tubes were double butted the seat tubes were single butted.

Both the Reynolds 531 and Vitus 172 Grand Jubile frames used 26.4mm seat tubes.

Seeing as how Vitus 172 was stronger than the standard Motobecane forks and stays used on earlier the Reynolds 3 main tube frames, the Vitus 172 frames were probably a few oz. lighter! BTW, Vitus 172 tubing sets came with the same fork blades used with the premium Super Vitus 971 tubing.


The early version Grand Jubiles with Huret Jubilee derailleurs had proprietary Huret dropouts. In late 1975 when the derailleurs were changed to Suntour Cyclone derailleurs, they started using Suntour GS dropouts. The 3rd picture shows an interim bike with a Suntour dropout and a Huret RD. The Suntour dropouts were campy compatible. Probably ~1977-78. Motobecane started using the new style Campy compatible dropouts with an integral cable stop - last picture.




Motobecane used their proprietary Nervex lugs on GJs until 1978 when they switched to short point Bocama lugs with cutouts.




My 1974 Grand Jubile frame was rescued from a dump after it had gone through a garbage compactor truck! The were no dent's but I had the frame realigned and after some quick touch up it looks great... from 10 feet! I built it up as a wet weather beater. After riding it for a while it became one of my favorites! It rides and handles great! so much for cheap forks and stays!



I picked a 1980 GJ frame and built it up as a touring bike. The original GJs had Club Touring frame geometry for fast group rides. The 1980 GJ has the same long wheel base and chain stays as the Grand Touring model from the late 80's early 90's. Notice the distance between the wheel and seat tube between the 1974 and 1980 bikes. I like the earlier GJs better.




This should give you enough info to figure out what you have..... On ounce of data is worth a pound of guessing!


verktyg

Chas.