Magnesium?



On Sat, 30 Jun 2007 17:57:46 -0400, [email protected]
(It's Chris) wrote:

>
>I don't think anyone has come up with a mag alloy that can offer the
>specs needed for a bicycle frame; Stiffness, strength, fatigue
>resistance, etc. but I could be mistaken.


Another shoot from the hip answer, but I don't think that's the issue.
They do some great things with magnesium. But, cost is very high.
That's the reason "mag wheels" are no longer made from magnesium
alloys, but from inferior aluminum alloys that weigh more and bend too
easily (bending being a solvable issue).

>Remember also, if the pro
>racers don't like it, it doesn't really matter what suits the rest of
>us.


Agreed :)

>Besides, carbon fiber is lighter, does meet the requirements and is much
>easier to manufacture. I don't think we will be seeing to many new
>exotic alloys anytime soon, the current direction is composites. I'm
>suprised they haven't started with boron fiber yet.


I think you need to combine this factor with the "trend" factor above.
Carbon fiber is in vogue. Oh, so trendy!
 
<[email protected]> wrote in message
news:[email protected]...
>
> I was under the impression that it wasn't used in frames more because
> it is difficult (expensive) to work with and this means a very limited
> market that is more or less dominated by carbon fiber for the
> lightweight segment. I'm looking at a used Pinarello Dogma. I like the
> sound of it because I want lightweight but I am concerned about the
> lack of stiffness in lightweight carbon frames in large sizes with
> lots of weight and (hopefully) lots of power. Do you think a magnesium
> frame would have a high likelihood of cracking? Which would be worse
> for a 200lb+ guy: a lightweight carbon frame or a lightweight
> magnesium frame?
>


Both are worse.

Greg
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On Jun 30, 10:43 am, "[email protected]"
<[email protected]> wrote:
> On Jun 30, 5:27 pm, DirtRoadie <[email protected]> wrote:
>
> > On Jun 30, 7:49 am, D'ohBoy <[email protected]> wrote:

>
> > > Frames have been made - Paketa, others... Stems as well. Don't know
> > > if still in production.

>
> > Fork sliders are typically magnesium.
> > Off the top of my head, other examples of magnesium bike parts have
> > included brake parts (levers, v-brake arms) and even wheel rims.http://www.amclassic.com/magnesium_clincher.html

>
> > DR

>
> I am in particular considering a welded magnesium frame, and a cnc-'d
> magnesium stem. I wonder what the pitfalls of using magnesium for
> these components is, and if there is any particular reason I should
> avoid them. I am interested in them for the light weight and strength,
> but if they are susceptible to breakage particularly from my weight
> I'll give them a pass.
>
> Joseph


Take a close look at what they are actually made of and you will see a
relatively small amount of the material is actually Mg..it is mostly
aluminum.