Paranoid thought of the day:Magnesium components - stability?

[bicycletricycle]

corrosion is a bigger concern than fire. Magnesium corrodes at an amazing rate when uncoated.

[zap]

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Originally Posted by martl

I know about precisely *one* bicycle part produced in larger numbers ever to be made out of Magnesium, which were the Avid Mag V-Brakes in the early 2000s. They were discontinued after an accident at their factory which, i believe, cost one life (see below).

Have a set on one of my wife's bikes. Added ti bits to it too.

Deda made a mag stem.

https://www.velonews.com/2002/06/bik...road-stem_2337

[Mark McM]

Originally Posted by bicycletricycle

corrosion is a bigger concern than fire. Magnesium corrodes at an amazing rate when uncoated.

This, I believe, was one of the big problems with the American Classic Magnesium rims. The brake tracks couldn't be reliably protected (any coatings would be quickly worn away), and the rim rapidly corroded.

[martl]

Originally Posted by Mark McM

This, I believe, was one of the big problems with the American Classic Magnesium rims. The brake tracks couldn't be reliably protected (any coatings would be quickly worn away), and the rim rapidly corroded.

well if a metal likes to interact with O², it likes to interact with O²...

[GOTHBROOKS]

what about the uk kirk precision magnesium frames?
those mag american classics were super lightweight though it was totally worth it.

[bicycletricycle]

Originally Posted by Mark McM

This, I believe, was one of the big problems with the American Classic Magnesium rims. The brake tracks couldn't be reliably protected (any coatings would be quickly worn away), and the rim rapidly corroded.

I had a friend who polished his mag 21. it needed polishing just about every other day after that.

[paredown]

BITD, a friend modified his own Honda 750 to go racing at the Salt Flats. This was a total budget operation, so he bought rough cast magnesium wheels that my dad helped him machine--and I know that dad was very careful while working on them.

The fun part was lighting the container of magnesium chips on fire when they were done--OMG, it was a pyromaniac's delight--burned hotter than bejeesus and was so bright you could not look directly at it. Oh, and it produced cool smoke...

[dddd]

Originally Posted by GOTHBROOKS

what about the uk kirk precision magnesium frames?
those mag american classics were super lightweight though it was totally worth it.

Ok, I have one of these Kirk Precision (road) bikes, and they aren't very light at all, certainly no lighter than an SLX frame and probably a few ounces heavier.

Their reputation for failure only matured after they began making mountain bike frames that were not-so-structurally-improved over their road frames.
Kind of like Lambert/Viscount with their use of cast-aluminum forks and bronze-welded thinwall Cr-Mo tubing, and with circlip notches (perfect stress-risers) in their bottom bracket spindles. These English companies marketed space-age bikes at a relatively low price which weren't so well-tested.

Their claim to fame (at least in their marketing efforts) was I believe a video of a car being driven over their frame without it being damaged!

Don't be surprised though if die-cast bicycle frames make a comeback soon. The die-casting process has improved greatly in recent years. Complex major portions of thin-walled aluminum alloy motorcycle frames sold by the big Japanese makers is now mature/proven technology used on some the most advanced motorcycles ever made.

[jischr]

Stella Azzurra made some mag stems, Vice Versa AZ91. I've been using a couple for several years. No issues with corrosion or anything else.

[bikinchris]

Originally Posted by 93KgBike

If you are riding in a lightening storm, and being struck by lightening, then yes your magnesium parts could burn - and the nickel metal-hydride or lithium ion batteries in your tech could explode - but so too could your carbon parts, your aluminum parts, even your steel and titanium parts.

But, "welder dies in bike-fire" is a story I've yet to hear.

ITM's "the stem" has never been recalled for failure, and still sets the bar (npi) for weight, even if it is almost equally ugly.

You should be fine, imho. Ride on.

Not to mention your gonads exploding and your socks flying off.

[93KgBike]

So the bike industry will be selling new magnesium alloy frames, that do not burn, the alloy melts.

Can't wait!

https://www.youtube.com/watch?v=HyTICWKzrpQ

[Bob Ross]

Another part, in case anyone's keeping a list:

About a dozen years ago fizik made saddles that afaik were only used for OEM (they never sold them directly) with magnesium rails. Identified with, appropriately enough, an "Mg" suffix. My 2006 Cannondale Synapse came stock with an Aliante Mg which is the saddle that made the Aliante my go-to ever since.

The magnesium rails broke after 10 years. If I had remembered my high school chemistry classes I would have tried to set the broken rails on fire.

[unterhausen]

it's tough to set something like a saddle rail on fire. Need to put it in your milling machine and reduce it to chips. Ti chips burn pretty well too, although someone sent me a video of trying to set chips on fire and they didn't burn all that well. But machine tools have been destroyed by Ti fires.

[Hindmost]

Originally Posted by Bob Ross

...Aliante Mg...

I have a hunch it was a manganese steel alloy.

[Mark McM]

Magnesium fire starters are popular among outdoors people. They are basically just a chunk of (pure) magnesium and a flint and steel. Slivers or chips are shaved off the magnesium block with a knife, and then the flint and steel is used to create sparks to ignite the magnesium. Magnesium burns hot, and will easily ignite tinder and wood shavings.