At 07:46 AM 11/1/06 -0800, Jerome & Elizabeth Moos wrote:
> 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.
>
It was probably an urban legend that race cars with magnesium parts would catch fire easily. I don't think it was a magnesium body, but an engine block that was blamed for the 1955 Mercedes Le Mans fire, but, obviously, it was the fuel that caught fire and started it all.
Back in the 1960s many race car parts were made of magnesium. Even the VW Beetle had a magnesium crankcase. Many race cars had magnesium wheels and the name "mag wheels" has stuck to this day for any kind of alloy or even chromed steel wheels. In Europe the magnesium alloy used for these light, high performance parts was known as Elektron and was usually gold anodized for corrosion resistance. I had a 1967 CZ motocross bike with these "gold" engine cases and brake drums. I never notice any problems with the spoke holes in the hubs. A couple of years later my next CZ no longer had magnesium parts, probably cost-cutting.
John Betmanis
Woodstock, Ontario
Canada