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Frenchbuilt

Hi, I am buying a couple of interesting Gitane frames which have stickers on them for Vitus Triple butted tubing.

Does anyone know what this tubing is?

Here is a poor photo from the seller.

Thanks, Dan

verktyg

Back in the 1980s manufacturers of the steel tubing tubing used on bikes produced a never ending variety of products with new names and descriptions. Some where the same steel alloy but different wall thicknesses of tubes, others were new steel alloys.

Ateliers de la Rive the French manufacturer of Vitus and Super Vitus tubing changed alloys a number of times during that era and thus new products and frame decals. For example, Super Vitus 971 and 980 were made from high strength, low alloy steel while Super Vitus 983 was made of a chrome-molybdenum steel. They all had comparable mechanical properties to Reynolds 531, Columbus, Tange and Ishiwata tubing.

Columbus started making some tubes out of exotic high strength steels and to a degree Ateliers de la Rive followed suite.

In the late 80s Ateliers de la Rive changed the names of their tube brands from Super Vitus 9xx to Vitus with different letter codes, i.e. TXO, XO, GTI and SM.

GTI is "triple butted". The wall thickness of the top tubes and down tubes start out at .9mm at the ends then drop down to .7mm for a small distance and are .6mm thick in the middle.

The seat tubes are .9mm thick at the bottom then go to .7mm and are .6mm at the top.

The steel used was a high strength chromium-molybdenum-vanadium alloy called 18 MCDV6.

It's a very light tube set.

Frenchbuilt

Thanks for info. on Vitus. When the frames come I will post some pictures.

Have been doing some research on butted tube forming and trying to figure out how the "inside" tool is removed from the thinner section.

It would seem that the tube would have to be opened up after forming to get tool out and then reformed to the right diameter.

Just another thing Chas since you have some Bertin Bikes.

I have a Bertin time trial frame I am building up and it is from the 1990s. Actually it is a Concorde frame re-sprayed and used as a Bertin/Shimano sponsored racing bike. This Concorde frame apparently was made in Italy and is so thin and light it is frightening.

Anyway, I was putting in a bottom bracket and went crazy when nothing
would go in smoothly.

I had a Stronglight cartridge bb with aluminum locking rings and being a bike from the 90's it should have standard iso threads.

Well, little threads of aluminum came out with the cartridge and I started checking that I had not screwed up the direction , etc.

Well, the SOB was done up in French threads so I was screwing in one side the wrong way!

My guess is that the frame came in to France with the bottom bracket uncut and then some bike shop had French taps laying around and figured to use an old French BB.

Anyway, I put in a French Sugino BB and added some Mavics cranks and
now everything is fine.

Luckily the aluminum cups went before the steel bb threads.

Moral: you can never really tell what you have and expect the unexpected.

Dan

Peter S. Horn

Dan,
The only thing that I would add is that, it was my impression, that GTI was, also, internally ribbed at the butted ends, a la Columbus SLX. If that is incorrect, Chas. et al, will correct me!
Peter H.