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Vitus brochure, including Durifort 
PostPosted: Thu Dec 20, 2007 12:11 am Reply with quote
vanhelmont
Joined: 11 Dec 2007
Posts: 242
Location: Florida
I thought this was interesting enough to deserve its own thread. One page gave me a "file not found" error, but the Durifort page downloaded properly.

http://www.yellowjersey.org/vitus.html
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Vitus Tubing REVISED 
PostPosted: Thu Dec 20, 2007 2:22 am Reply with quote
verktyg
Joined: 14 Jan 2007
Posts: 2810
Location: SF Bay Area
Ateliers de la Rive was a French manufacturer of specialty steel tubing. From the early 1980s through 1990s they dabbled in aluminum tubing, also CFRP carbon fiber reinforced plastic tubing. They were well known for their Vitus aluminum and composite frames.

This Classic Rendezvous link about Vitus tubes by Norris Lockley has a few incorrect bits of information concerning Ateliers de la Rive's products.

http://www.classicrendezvous.com/France/Vitus_history.htm


The Ateliers de la Rive tubing catalog posted on the Yellow Jersey site came out about 1977 or 78. The catalog listed their then current product offering: Super Vitus 971, Vitus 172, and Durifort/Rubis 888 tubesets.

http://www.yellowjersey.org/vitus.html

In that catalog Durifort and Rubis 888 were lumped together as a single straight gage tube set.


I gathered the additional information below from some earlier sources including "Delong's Guide to Bicycles & Bicycling" first edition 1974.

In the 1930s there was a French brand of light weight tubing called Rubis. It's unclear whether it was affiliated with Ateliers de la Rive but it may have been a predecessor of Durifort and Vitus tubing .








In the early 30s Ateliers de la Rive introduced Durifort butted tubes made of French designation A35 carbon steel that had about 2/3rds the strength of Reynolds 531 and similar alloy steels. It was first named DURIF and then later called DURIFORT.

Here's an early French ad for Durifort tubing:



Durifort frame decals from the mid 60s:





Durifort decals from the 1970s:







BTW, only the top and down tubes on a "double butted" frame are double butted. Seat tubes and steerers are single butted. The other tubes usually have straight wall thicknesses or slightly tapered thicknesses.


Durifort tubing was made from seamed tubes. Up through the late 1970s the Durifort 3 main tubes were butted. After they were drawn and rolled over mandrels during the butting process, any potential weakness of seamed tubing was eliminated.

Tubing wall thicknesses for Durifort "butted" tubing during that period:

3 main tubes 1.1mm/0.75mm butted
chainstays 1.0mm
seatstays 1.0mm
fork blades 1.5mm
head tube 1.0mm
steering tube 1.6mm/2.6mm tapered


Ateliers de la Rive also made sets of 3 straight gage main tubes out of the same steel as Durifort. They had a 0.8mm wall thickness and were called Rubis 888 tubing. Bikes made with Rubis main tubes had an oval yellow seat tube sticker "Rubis 888" similar to Rubis seatpost sticker.



The bikes made of 3 Tube Rubis main tubes were slightly above entry level and rarely made it to the US.


The name Rubis 888 was later changed to Durifort 888 and complete straight gage Durifort 888 tube sets were produced.

Rubis 888 (later Durifort 888) Wall Thickness

3 main tubes 0.8mm straight gage
all other tubes same as regular Durifort

There was also Durifort 788 which may have had a top or seat tube with 0.7mm wall thickness.

Many middle to top quality French bikes from the 1960s up into the early 70s had frames made with Reynolds 531 butted main tubes and Durifort forks and stays. I always viewed as any advertising ploy because the Reynolds main tubes most commonly used back then had just about the same 1.0mm x 0.7mm wall thickness as Durifort main tubes.


Plain Vitus tubing came out in the 1930s too. I've never seen any technical information on early Vitus tubing but it was considered to be equal to Reynolds 531 at the time and was probably much lighter than Durifort.






Vitus 172 tubing appeared in the US in the early 70s. I never saw any bikes made with Vitus 172 until the late 70s when Motobecane started making several upper end models using that tubing.

Vitus 172 tubing was seamed and made in the same way as Durifort except that it used same fork blades as the stronger Super Vitus tubesets. It was also made of a stronger low alloy steel than Durifort that was within 5-10% of the strength of Reynolds and Columbus tubing.

The wall thickness of Vitus 172 was the same as Durifort butted tubing except for the fork blades which were 1.2mm thick. These were the same fork blades as used on the premium Super Vitus 971 tubesets. The rest of the tubes had the same wall thickness as Columbus SP tubing and Reynolds 531 1.0/0.7 mm tubes.





One correction th the CR Vitus article linked above concerns Vitus 171 which was introduced much later than Vitus 172. I've not seen any technical information about Vitus 171.


Vitus 181 tubing came later and was made from a Chrome Moly alloy steel. It was designed to compete against Reynolds 501 Chrome Moly steel tubing used in mid level bikes during the 1980s.


In the 1980s there was also Vitus 888 tubing which was probably made from the same steel as Durifort or Vitus 171/172/181? The 3 main tubes were 0.8mm thick thus .8.8.8 on the frame decals. They also made some 988 and 999 tubing which I assume had straight gage .9mm wall thickness main tubes.


The top of the line tubing from Ateliers de la Rive during the 70s was seamless Super Vitus 971. It had the same strength as Reynolds 531 and Columbus tubing. Seamless tubing is usually considered to be better than seamed tubing.





Super Vitus 971 tubing wall thicknesses:

3 main tubes 0.9mm/0.6mm butted
chainstays 0.8mm
seatstays 0.8mm, available with 14mm or 16mm diameter tubes at the large end.
fork blades 1.2mm
head tube 1.0mm
steering tube 1.6mm/2.6mm tapered

This is the same wall thickness as Columbus SL tubing. Reynolds 531 had tubing sets with similar wall thicknesses too. Frames made with thinner walled tubes took more care in brazing to prevent overheating but produced lightweight bikes in the 21 Lb. range when equipped with sewups.

In the early 70s Super Vitus 971 was made with a French steel designated as XC-38. By the late 70s, they switched to XC-35 steel that was a slightly different formulation than XC-38. These are both low alloy high strength steels.

There was also Super Vitus 980 and 983.

Super Vitus 980 was used from the late 1970s until the late 1980s. I was made of the same steel as SV 971 except SV 980 had some of the thinnest wall thickness tubes used in production bikes of that era. It had a reputation for being "whippy" in frames 60cm and larger. In smaller frames it was maybe a little smoother riding than Reynolds 753R.



Super Vitus 983 was made of a chrome molybdenum alloy steel that had very high strength. The tubing wall thickness was between SV 971 and SV 980.



By the late 1980s marketers took over the tubing industry and a lot of "new" types of tubes were introduced.

Most alloy steels were developed after 1900. Up until that time carbon steels were the most common kinds of steel. Carbon steels usually have less than 5% alloying elements by weight.

The addition of small amounts of manganese, chrome, molybdenum, vanadium, nickel and/or other alloying elements can greatly increase the strength of steel but more importantly alloy steels (with more than 5% alloy content) have much higher fatigue resistance. They can withstand many more cycles of flexing before failure.

Tubing made of stronger more fatigue resistant steels can be made thiner thus producing lighter bike frames.

Chas.
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Vitus brochure, including Durifort 
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