First … thanks for the very kind comps from thread readers.
Now to speak to Woz's comments and questions: I'm not an expert on frame design, and I failed physics at school. So, I cannot speak to Mr Bontrager's article. But as an aside, as well as in reference to what he said about motorcycle frames, I did do some motorcycle racing back in the Cretaceous. And I experienced some pretty hair-raising moments riding an up-rated engine that overpowered the frame. I experienced the frustration of not getting power to the ground because the frame was flexing in direct proportion to increasing throttle when exiting corners. There is my sum total of real-world experience with frame flexing.
As a casual "exercise rider" the geometrical stability of the Vitus 979 is not an issue. Old Ned may want to comment here. And my two thumbs are up for his racing efforts aboard this classic machine. Good on ya' mate! I was glued onto your linked picture
So, the issue does not affect my riding. I rarely sprint, and most of my stress and strain is involved in fighting some headwind blowing into eastern Japan from northern China or Mongolia. The Hirose River levee road is a sort of funnel for moving air. Anyway, it far as one can get from a sprint to the finish line among a pack of insane super humans flushed with adrenilan.
How do they hold up? Well, I don't pound this frame up and over curbs and other urban impediments. For one thing, I have too much respect for the ageing GP-4's. Giant potholes are not an issue here — unless maybe you're in the areas most affected by the 3-11 tsunami. I stay clear. Stress is not an issue. The bike feels very much like my 531 frames — not quite as "silky", but I never get the sense of anything wondering. And I don't have shifting problems on climbs.
To conclude this bit, I do not think that the sports enthusiast need worry. That being said, at least one writer has opined that the brazed steel frames will be flying about the planet when the bonded ones have been grounded. We will see. I do recall a surviving De Havilland Mosquito with a glued wooden airframe was doing astonishing displays at British airshows for a decade before a tragic mishap involving maladusted carburettors caused the destruction of the aeroplane, and the instant death of both the spectacular pilot and the man in the right hand seat. An exhaustive investigation of this incident concluded that the 1940's airframe was not at fault.
Now let's look at these questions another way. Al Vitus frames and their cousins were produced by the thousands. The next generation were similar designs using Al lugs and bonded carbon tubes. If there were significant horror stories of failure, where are the iconic reports? I cannot say that there are none, but I haven't found them. They have not come up in the articles and forums I have been trawling through for years. And if someone comes up with some on this thread, we could also pull in some stories of failed welds and brazing — cracked and failing steel tubing.
Some years ago, there was guy in Vancouver, B.C. who was a proprietor of a bicycle repair service. In addition, he did restorations — in particular, Vitus. His signature on-line advert featured a guy holding a failed Vitus frame member. There were no accompanying statistics or apocryphal stories. But there were some interesting adverts for spare frame parts, and most importantly, a description of a restoration service for Vitus frames — the dismantlement an rebonding of frames.
You can check it out, but some time ago, this restoration service seemed to be a fading enterprise, whether from lack of demand or for a myriad of other reasons — who knows? But it was interesting to see, and it was AFAIK the only site on-line offering such a thing.
Could he have been offering the real thing? Perhaps. Even some years go when this site was being revised and cared for, the chemistry and techniques very possibly had come a long way from when aerospace companies were charged with the assembly of bonded bicycle frames.
In 1980 I attended an industrial exhibition in Paris. I spent an hour in the aerospace section where the salient features were micro machining and an exhibit of aggregate sections of airframes (polymers and aluminium) that were fabricated without fasteners … but rather with adhesives! In my deficient French I was able to clarify with the exhibitors that this was the future of airframe construction. All these years on, so it is with sections of airliners as well as in the production of the world's more expensive military airframes.
If I were one of the world's few thousand or so supermen (or superwomen) charging down twisting mountain descents at 70 Kph … and being quite mad enough to qualify and ride a bonded, obsolete Al bicycle in one of the great classic alpine races, I might feel more secure if the frame were new, or at least remanufactured. On the other hand, for my recreation and velo madness, my 979 gives me no concern.
And one last thing: I think that it can be said that Sean Kelly had a distinct and special relationship with the Vitus frame. This involved his style of riding, his phsique and the size of frame he was riding. And let us remember that any of his frames would have been the so-called 'A' line products with pinned interfaces. How much the this contributed to any success we may never know. Anyway, pinning was a common practice for steel team or services des courses frames back in the day — Mercier being a notable example.
