I've read that another problem with Teledynes was that they tried to use metallurgically pure titanium, as opposed to alloys. This may have applied to Speedwell also. Not quite sure what this comment meant - whether pure titanium is brittle when drawn into tubes, or whether the alloying metals make titanium easier to weld properly. Frankly, I find it odd a large high-tech company like Teledyne, which I believe was involved in military aerospace contracts, would be ignorant of the advantages of titanium alloys. Yet, whether pure titanium or no, there were definitely problems with the DT neckdown, the forks, and perhaps sometimes the welds. Kind of makes you wonder about the safety of F-16s, doesn't it?
Regards,
Jerry Moos
PeterGrenader wrote:
> A lot of the Teledyne's broke on the downtube where the diameter decreased to
> accept the clamp on shifters. I've seen about 5 that bit the dust in that
> spot. There may have been other places where they failed as well.
>
> As you know, titanium alloy on it's own is strong. Strong enough to be the metal
> of choice for fighters. It's the welding that screws things up. When I saw the
> carbon rear-end Colnago Ti bikes unveiled at interbike in 1999, I was horrified
> at the dark discoloration around the welds, which, if I remember Bill Holland's
> comments is a indication that the Oxygen was not completely purged when the
> tubes were welded together (a big no no) which leads to brittle junctions and
> are prone to failure under repeated stress.
>
> While i do not pretend to be an expert in the specific process steps involved in
> making a clean Ti weld, I have watched Bill at work and have seen the
> precautions he meticulously goes through to assure their strength. it's
> complicated and justifies the cost of the frame. If everything is done
> correctly, you will have a frame that will last very long time. Hugo Derosa
> himself you'll remember commented that he felt titanium was the material of
> choice for bike frames, it's only set back being the cost involved, most f which
> have to do with the processes required for manufacturing.
>
> Peter
> LA
>
> Cino1947@aol.com wrote:
>
> > I've read about breakage with titanium frames from Colnago and Teledyne.
> > Where are the breakages occuring? I can't imagine that the titanium itself
> > would break so easily. Russia is supposed to have very extensive experience
> > with titanium fabrication. Welding titanium has to be done in an atmosphere
> > of inert gas (argon) to prevent oxygen contamination resulting in a brittle
> > joint.. I would guess that the breakages of these frames would occur at the
> > joints due to improper welding techniques, but I don't know for a fact.
> > Josh Berger
> > In a message dated 11/11/00 5:27:00 PM Eastern Standard Time, Cino1947
> > writes:
> >
> > << The BiTitan problems were:
> > - made in Russia of alleged high quality Ti but who knows (and many suspect
> > foul play!)
> > - Breakage.. All hard ridden (and some soft pedaled) BiTitans seemed to
> > break.
> > - Lack of support. Ernesto is said to be indifferent to breakage, "Itsa all
> > your fault!" his interpreter is said to have uttered. Todsun, the last
> > importer of Colnago to the USA, is said to have a room full of broken
> > BiTitans at their offices. They were contemplating how, indeed, they were
> > going to eat them.
> > >>