Re: components manufacturing methods

bicycle_disciple wrote:
I speculate this topic may have been beaten to death. I'm lazy to go
over the innumerable archives of RBT, so let me shoot out the
question.

What manufacturing methods are being used in high end components these
days and how do each one affect strength, failure due to fatigue,
stiffness etc? I wonder if cranksets are cast at all in these days
where cnc machining and so on is rampant technology to cut costs. Most
cranksets I read about (Stronglight, Zero Gravity,FSA) talk about CNC
machining and I've also heard some folks who think these methods don't
produce enough strength and durability as forging or casting and so
on. These days theres carbon every here and there, especially in
carbon cranksets, so what kind of manufacturing is done here to make
these parts? I'm not only looking for an answer to high end components
which could be mostly made in-house, but also the ones that people
with an average budget ride everyday, and whose parts are outsourced
to Taiwan, China etc...


-BD


you seem to be confused about how cnc is different from casting or forging. cnc is simply a machining process that's used for finishing, not for basic form creation like casting or forging.

briefly, forgings are much better in fatigue than castings. a subset of casting is thixoforming, which is better than straight casting, but still not as good as forging. thixoforming is very fashionable with certain manufacturers like avid.

for fatigue, high quality carbon fiber is best, followed by cold forging, then hot forging, then thixoforming, with casting a distant runner-up. carbon that is basically a veneer on top of an aluminum substrate is debatable.
.

Relevant Pages

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