If I remember correctly, Mercedes-Benz had a magnesium bodied sports prototype in the 50's or early 60's. One such car crashed into the crowd at LeMans and in the ensuing fire the magnesium body burned with great intensity. Several spectators were killed an a number of others injured. Mercedes withdrew from racing for a number of years as a result.
I seem to recall that Avocet in the early 80's announced and advertised "Model III" hubs, to be made by Ofmega probably. They were to have magnesium bodies and I think titanium axles. I'm pretty sure these were never actually sold. Aside from the dubious value of flammable metal bodies, magnesium is pretty brittle, and I would expect hub flange cracking at the spoke holes would have been a big problem.
It seems construction materials become "in vogue" at certain periods of time, often soon after they first become affordable enough for commercial use. Typically, one sees the "hot" material used in all sorts of applications, including those in which it has no real advantages and even some real disavantages. Engineeers are not immune from being influenced by fashion.
Regards,
Jerry Moos, BSEE, BSChE Big Spring, Republic of Texas
Joseph Bender-Zanoni <joebz@optonline.net> wrote: I see magnesium parts now and again in various applications and I am usually very unimpressed. I have been out of the engineering game for ten years what I remember was it had big corrosion problems and little design data. If you can't figure out the effects of stress concentrations, corrosion and fatigue, you basically can't do a design except for some stupid lump like the Kirk. For these reasons and because of fire hazards, Magnesium was forbidden for aerospace designs. Even 7075 aluminium is probably underused in bicycle applications. But corrosion is tricky. I had a seatpost part turn to a chalklike oxide.
Beryllium was allowed for specialty purposes but poisonous in the machine shop. The next step in ultra low density metals would be Lithium. I'm waiting for that.
Joe Bender-Zanoni Great Notch, NJ
Chuck Schmidt wrote:
> Amir Avitzur wrote:
>
>> Anybody ever heard of Magnesium tubed road bikes?
>> Someone mentioned that there was a maker in the UK at one time.
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> Kirk Precision... I sold one on eBay about seven or more years ago.
> They were HEAVY DOGS and pretty much a complete failure.
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> One on eBay recently: Item: 300041223845
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> One on First Flight web site:
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> Chuck Schmidt
> South Pasadena, Southern California
> United States of America
> http://www.velo-retro.com (reprints, t-shirts & timelines)
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