I was looking up the tensile strength of carbon fiber. This is a great deal dependent upon the direction of load since carbon fiber lay-ups are about 60% resin. Resin itself does not bear loads well but it can hold together load bearing fibers such as carbon, Spectra, Kevlar, Zylar or Vectran. Kevlar is the strongest material known but it is a little heavier than Spectra. Carbon Fiber can have a tensile strength of 6,000 MPascals. (4340 steel is 1,700.)

Resins do not have strength even in the ballpark with these fibers and it is important to know that at around 1/3rd of the strength they have (~80 MPascals) resins begin to grow micro-cracks which then slowly connect with other microcracks until the resin fails and that leaves the fibers with no tensile strength to side loadings.

Of course this is dependent upon the loadings but due to the roads and condition thereof, this occurs pretty rapidly. Since carbon fiber bicycle framesets are designed for the lightest weight in mind this means that there is a relatively short life expectancy on carbon fiber construction. Of course this is all relative since as weight of these structures goes up, the distance these micro cracks have to grow to meet with others increases.

The larger companies are turning more and more to heavy compression of the layups so that more and more of the resins are pressed out of the layups and the fibers themselves take more of the loads than the resins. But while this improves the lifespan of a carbon fiber frameset, it is only by a minor degree. All of the space between fibers must be filled with resins or the strength disappears.

Carbon forks tend to have longer lives simply because the loads are all from a single direction and it is easier to build them without areas that are loaded only by the resin.

The purpose of all of this is to explain that older used carbon fiber frames are on the market bit necessarily because they are stronger or even good, but because they haven't been stressed long enough for high enough to cause catastrophic failures.

While Jay has told us that he has had failures of steel and aluminum which fail for different reasons, they seldom fail catastrophically and you need to be aware of that. If safety is your desire metal frames are probably more up your alley.

I noted that at least one of the teams in the Vuelta were riding aluminum bikes this is likely to cause an attempt to make lighter aluminum frames that are as rigid as the carbon fiber frames. Unfortunately this will also cause more stress failures in such frames making them as unreliable as carbon fiber.

Down in my garage I have an Eddy Merckx Elite which is an aluminum bike that rides about as good as you could ever want in such a large frameset (19 lbs at 61 cm without any attempt to be light).

So it is possible that your future could be aluminum.

On Friday, September 10, 2021 at 8:47:43 PM UTC+2, cycl...@gmail.com wrote:

>
> I noted that at least one of the teams in the Vuelta were riding aluminum bikes this is likely to cause an attempt to make lighter aluminum frames that are as rigid as the carbon fiber frames. Unfortunately this will also cause more stress failures in such frames making them as unreliable as carbon fiber.

Can you tell us what Pro team that was? I saw only CF frames.

> So it is possible that your future could be aluminum.

Everything is possible.

Lou

On 9/11/2021 6:01 AM, Lou Holtman wrote:
> On Friday, September 10, 2021 at 8:47:43 PM UTC+2, cycl...@gmail.com wrote:
>
>>
>> I noted that at least one of the teams in the Vuelta were riding aluminum bikes this is likely to cause an attempt to make lighter aluminum frames that are as rigid as the carbon fiber frames. Unfortunately this will also cause more stress failures in such frames making them as unreliable as carbon fiber.
>
> Can you tell us what Pro team that was? I saw only CF frames.
>
>> So it is possible that your future could be aluminum.
>
> Everything is possible.
>
> Lou
>

Yes, possible to the extent one might bear the various costs
(not only financial).

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

On Saturday, September 11, 2021 at 4:01:35 AM UTC-7, lou.h...@gmail.com wrote:
> On Friday, September 10, 2021 at 8:47:43 PM UTC+2, cycl...@gmail.com wrote:
>
> >
> > I noted that at least one of the teams in the Vuelta were riding aluminum bikes this is likely to cause an attempt to make lighter aluminum frames that are as rigid as the carbon fiber frames. Unfortunately this will also cause more stress failures in such frames making them as unreliable as carbon fiber.
> Can you tell us what Pro team that was? I saw only CF frames.
> > So it is possible that your future could be aluminum.
> Everything is possible.

Damned if I know. That was mentioned on the Vuelta coverage and we saw riders jumping up after a mass crash and riding off without even looking at their bikes - perhaps it was Ridley that makes aluminum bikes that ride so well that I have no idea why they ever changed to carbon fiber since they already made aluminum bikes that weighed the UCI limit.

On Saturday, September 11, 2021 at 7:02:26 AM UTC-7, Tom Kunich wrote:
> On Saturday, September 11, 2021 at 4:01:35 AM UTC-7, lou.h...@gmail.com wrote:
> > On Friday, September 10, 2021 at 8:47:43 PM UTC+2, cycl...@gmail.com wrote:
> >
> > >
> > > I noted that at least one of the teams in the Vuelta were riding aluminum bikes this is likely to cause an attempt to make lighter aluminum frames that are as rigid as the carbon fiber frames. Unfortunately this will also cause more stress failures in such frames making them as unreliable as carbon fiber.
> > Can you tell us what Pro team that was? I saw only CF frames.
> > > So it is possible that your future could be aluminum.
> > Everything is possible.
> Damned if I know. That was mentioned on the Vuelta coverage and we saw riders jumping up after a mass crash and riding off without even looking at their bikes - perhaps it was Ridley that makes aluminum bikes that ride so well that I have no idea why they ever changed to carbon fiber since they already made aluminum bikes that weighed the UCI limit.
I should say that my Eddy Merckx Elite weighs in at the same as my Trek Madone did.

On Saturday, September 11, 2021 at 4:01:35 AM UTC-7, lou.h...@gmail.com wrote:
> On Friday, September 10, 2021 at 8:47:43 PM UTC+2, cycl...@gmail.com wrote:
>
> >
> > I noted that at least one of the teams in the Vuelta were riding aluminum bikes this is likely to cause an attempt to make lighter aluminum frames that are as rigid as the carbon fiber frames. Unfortunately this will also cause more stress failures in such frames making them as unreliable as carbon fiber.
> Can you tell us what Pro team that was? I saw only CF frames.
> > So it is possible that your future could be aluminum.
> Everything is possible.

I don't know about the grand tours, but Bora Hansgrohe and Quick Step used the Specialized aluminum Allez in some races. https://www.bikeradar.com/news/specialized-allez-sprint-schwalbe-classic-criterium/

From a safety standpoint, I don't think there is much risk of catastrophic failure of any frame absent a crash. CF frames don't just fall apart without warning, and the usual non-crash failures based on my conversation with the folks at Ruckus are cracks and rubs from wheels, impacts from tool drops and that sort of stuff. https://ruckuscomp.com/news/category/featured-repair

In a good crash, however, CF frames can vaporize, but the rider is launched anyway; however, when the rider gets up from the pavement, he or she has to get a new frame rather than having ye olde frame shop straighten the forks and replace some tubes -- or just live with the buckled tubes and a slightly steeper steering angle.

I'm amazed Tom is so positive about CF forks. All my bikes have carbon forks, but they're the only thing that I worry about based on reported (take that with a grain of salt) JRA failures. I am very wary of squirrels. These fine Specialized forks (looks like a Roubaix) withstood the squirrel test: https://www.thesun.co.uk/wp-content/uploads/2016/11/nintchdbpict000284504998-e1479985846886.jpg?w=1440

-- Jay Beattie.

On 9/11/2021 9:19 AM, jbeattie wrote:
> On Saturday, September 11, 2021 at 4:01:35 AM UTC-7, lou.h...@gmail.com wrote:
>> On Friday, September 10, 2021 at 8:47:43 PM UTC+2, cycl...@gmail.com wrote:
>>
>>>
>>> I noted that at least one of the teams in the Vuelta were riding aluminum bikes this is likely to cause an attempt to make lighter aluminum frames that are as rigid as the carbon fiber frames. Unfortunately this will also cause more stress failures in such frames making them as unreliable as carbon fiber.
>> Can you tell us what Pro team that was? I saw only CF frames.
>>> So it is possible that your future could be aluminum.
>> Everything is possible.
>
> I don't know about the grand tours, but Bora Hansgrohe and Quick Step used the Specialized aluminum Allez in some races. https://www.bikeradar.com/news/specialized-allez-sprint-schwalbe-classic-criterium/
>
> From a safety standpoint, I don't think there is much risk of catastrophic failure of any frame absent a crash. CF frames don't just fall apart without warning, and the usual non-crash failures based on my conversation with the folks at Ruckus are cracks and rubs from wheels, impacts from tool drops and that sort of stuff. https://ruckuscomp.com/news/category/featured-repair
>
> In a good crash, however, CF frames can vaporize, but the rider is launched anyway; however, when the rider gets up from the pavement, he or she has to get a new frame rather than having ye olde frame shop straighten the forks and replace some tubes -- or just live with the buckled tubes and a slightly steeper steering angle.
>
> I'm amazed Tom is so positive about CF forks. All my bikes have carbon forks, but they're the only thing that I worry about based on reported (take that with a grain of salt) JRA failures. I am very wary of squirrels. These fine Specialized forks (looks like a Roubaix) withstood the squirrel test: https://www.thesun.co.uk/wp-content/uploads/2016/11/nintchdbpict000284504998-e1479985846886.jpg?w=1440
>
> -- Jay Beattie.
>

Without any formal engineering training, nor privy to
statistical quality control procedures in slave labor PLA
fork production facilities, I can only look at the
experience of this industry, where carbon forks are common,
cheap and reliable. Or as reliable as any high volume
consumer product with liability insurance anyway.

I'm been writing here for twenty years that the plague of
carbon fork failures, though often predicted, has yet to
occur. But who knows? Another couple of decades with tens of
millions per year could prove me wrong.

Do carbon forks fail? Yes. But, just like P&W engines, not
every day:

https://abcnews.go.com/US/plane-makes-emergency-landing-philadelphia/story?id=54530003

Unlike Tom, she died.

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

On Saturday, September 11, 2021 at 7:19:46 AM UTC-7, jbeattie wrote:
> On Saturday, September 11, 2021 at 4:01:35 AM UTC-7, lou.h...@gmail.com wrote:
> > On Friday, September 10, 2021 at 8:47:43 PM UTC+2, cycl...@gmail.com wrote:
> >
> > >
> > > I noted that at least one of the teams in the Vuelta were riding aluminum bikes this is likely to cause an attempt to make lighter aluminum frames that are as rigid as the carbon fiber frames. Unfortunately this will also cause more stress failures in such frames making them as unreliable as carbon fiber.
> > Can you tell us what Pro team that was? I saw only CF frames.
> > > So it is possible that your future could be aluminum.
> > Everything is possible.
> I don't know about the grand tours, but Bora Hansgrohe and Quick Step used the Specialized aluminum Allez in some races. https://www.bikeradar.com/news/specialized-allez-sprint-schwalbe-classic-criterium/
>
> From a safety standpoint, I don't think there is much risk of catastrophic failure of any frame absent a crash. CF frames don't just fall apart without warning, and the usual non-crash failures based on my conversation with the folks at Ruckus are cracks and rubs from wheels, impacts from tool drops and that sort of stuff. https://ruckuscomp.com/news/category/featured-repair
>
> In a good crash, however, CF frames can vaporize, but the rider is launched anyway; however, when the rider gets up from the pavement, he or she has to get a new frame rather than having ye olde frame shop straighten the forks and replace some tubes -- or just live with the buckled tubes and a slightly steeper steering angle.
>
> I'm amazed Tom is so positive about CF forks. All my bikes have carbon forks, but they're the only thing that I worry about based on reported (take that with a grain of salt) JRA failures. I am very wary of squirrels. These fine Specialized forks (looks like a Roubaix) withstood the squirrel test: https://www.thesun.co.uk/wp-content/uploads/2016/11/nintchdbpict000284504998-e1479985846886.jpg?w=1440

The stress and strain on a fork is very well controlled and not at all like a frameset which has stresses and strains in 3 dimensions.