On 7/5/2019 9:33 PM, AMuzi wrote:
On 7/5/2019 4:33 PM, Tom Kunich wrote:
My friend just returned from Italy on a tour up the entire length of
the east coast.

He visited the factory that built his and his wife's custom steel frames.

They also build carbon fiber frames and sponsor a Pro team. When Mike
asked them about their reliability the company official that was
showing them around said that he would not recommend ANYONE buying a
carbon fiber frameset.

He said that pro teams replace their framesets generally each race
because they cannot take the chance injuring a rider with a failure.
This is a famous Italian marque that has made bicycles since 1957. So
the opinion of the factory should bear some weight.

Global Cycling Network has performed a series of tests of carbon
handlebars vs aluminum. What they discovered should come as no
surprise to anyone - carbon has four or five times the fatigue
resistance of aluminum.

So under loads that are at or under their designed strength they have
a much longer life than aluminum.

However, at loads above their designed strength carbon fiber will
break whereas aluminum tends to bend instead of break.

What this means is that a properly designed and manufactured carbon
fiber bike should have four or more times the lifespan of an aluminum
frameset designed to the same limits.

There is only one thing wrong with this theory - carbon fiber
construction has a number of problems - they can be build more easily
with flaws than can aluminum or steel bikes and since everyone is
going for the lightest possible bikes these days, the design of carbon
bikes and their strength isn't known closely enough to be as reliable
as necessary.

So if you're Joe Modern and want a super-light carbon frame be honest
with yourself and realize that your bike could break and it could
occur at the worst possible times. If you're a Pro racer it is your
business to be competitive at the highest levels. If you are not
perhaps another material may be more appropriate.


We almost never see modern aluminum race bars bent, they just snap.
Back when they were thicker and less tempered they bent, but that's over
for race quality bars now.

It seems it's almost a law of nature that the higher the strength, the
lower the ductility. Often, that means the less warning before fracture.


--
- Frank Krygowski