On Friday, July 5, 2019 at 6:33:37 PM UTC-7, 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.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

I went back and watched a couple of the carbon vs aluminum bars. He showed a fairly large number of carbon bars with voids and failures ranging from visible to total failures.

Then he began talking about aluminum bars. He said that for a while they were making ultra-light aluminum bars weighing in at 200 grams. He said that they didn't even bother with inspecting the bars but replaced them yearly because they would have catastrophic failures. He then said that now they make the bars 250 grams. I assumed from his statements that they were a hell of a lot more reliable because of the 25% additional weight.

After what I saw in those video's it sort of gives me the willies about any ultralight bars.

No problem since the Chinese CF bars are somewhat heavier than the expensive ones. Another video compared the American made Enve carbon rims with the Chinese. The Enve had what I'd consider a slightly better shape but it also had some visible voids. They did not appear to be in areas that are important but a crash may disable the bike because of that.

So in regard to your posting - perhaps the bars you've been seeing fail were the ultralights and not the newer. The failure of all of his stack of carbon bars certainly couldn't give you confidence in carrying on after a crash.