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Old June 24th 19, 12:17 AM posted to rec.bicycles.tech
JBeattie
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Default Steel is Real and Carbon is Lighter

On Sunday, June 23, 2019 at 3:05:17 PM UTC-7, Tom Kunich wrote:
On Saturday, June 22, 2019 at 8:10:16 PM UTC-7, jbeattie wrote:
On Saturday, June 22, 2019 at 7:29:10 PM UTC-7, John B. wrote:
On Sun, 23 Jun 2019 05:17:38 +0700, John B.
wrote:

On Fri, 21 Jun 2019 09:15:50 -0700 (PDT), Tom Kunich
wrote:

On Wednesday, June 19, 2019 at 9:49:48 AM UTC-7, duane wrote:
On 19/06/2019 10:25 a.m., jbeattie wrote:
On Tuesday, June 18, 2019 at 8:06:37 PM UTC-7, Frank Krygowski wrote:
On 6/18/2019 1:24 PM, jbeattie wrote:
On Tuesday, June 18, 2019 at 9:49:50 AM UTC-7, Frank Krygowski wrote:

For ordinary riding? No, most tiny improvements make no noticeable
difference. Even though we all know the near-magic power of red paint.


What is a "tiny improvement"? The frame on my Emonda probably weighs less than the Columbus steel forks off my last custom racing bike. Those things were suitable for clubbing baby harp seals or home defense. Weight and stiffness do matter when climbing. If we're talking about aero bits, that's harder call -- except that dopes on aero bars riding in packs can result in a massive worsening of your riding experience. Wearing aero shoe covers may keep your feet warmer on chilly mornings, which might make you faster. It all adds up.

Stiffness probably does not make a detectable difference, unless the
frame is so flexible that things are scraping. Remember the discussion
we had about the bike magazine's test of modern stiff CF frames vs.
older, heavier steel frames? The test riders gushed about how the
stiffness improved their climbing, but the math showed the speed
difference was precisely what would be predicted by the weight difference.

Weight matters when climbing. If getting to the top of the hill before
your buddy is really, really important, a lighter bike will help by
whatever the percent difference in total bike+rider weight. If a 160
pound rider changes his 20 pound bike for an 18 pound bike, he should be
about 1% faster up a steep hill. Whoopee!

Make that a 5lb weight difference. You need to borrow a well-fitting modern 15lb racing bike with an appropriate gear range and then do a long ride with lots of hills. It's not a subtle or imagined difference compared to a T1000 or old-school steel sport touring bike, particularly if you're trying to keep up with others.

-- Jay Beattie.


5lbs? My Tarmac is probably closer to 12 lbs lighter than my cro moly
Volpe.

And no in reality it's not a subtle or imagined difference. And no,
it's not just about weight unless everything else is exactly the same.

I changed my Look pedals from CX 6 cyclocross pedals which are very easy to get into and put 206's on which were much lighter. Then since I had those 50 mm deep clinchers just sitting there I installed those The "out-the-door" weight was 21.7 lbs. for the Pinarello. I'm pulling my Basso apart to refinish it and I have another set of cheap Chinese tubeless wheels that I'll install when it get's back together. Also I think that my 44 mm bars are too wide so will reduce this to 42 mm. Chinese carbon bars as well. I think that I can keep a steel bike and have it about the same weight as the Colnago. Granted that the Colnago is not an ultra-light but my friend is touring Italy and he went to a bike factory and they advised him against buying carbon. They said that they support a racing team with these ultra-lights but that they are replaced every single race. They say that there's no way that you can get any reliability out of a piece of cloth that tears with resin on it that cracks.

That last is a rather strange statement given that practically all
modern recreation and work boats are made from a mixture of cloth and
resin. Do you mean that my 15 year old, 40 ft sloop, that had sailed
across the pacific ocean and that I sailed from Thailand to Australia
and back was prone to crack?

Or is this just another of your poorly thought out and wild eyed
statements.


As an addendum to the above I found a site that had tested a number of
carbon composite samples. The average of 4 separate test samples was
982.5 MPa or 142,499psi. In comparison the ultimate tensile strength
of "mild steel" (Aisi 1018) is 440 MPa or 63,816 psi.
http://www.scielo.br/scielo.php?scri...92006000100016
https://www.azom.com/article.aspx?ArticleID=6115

As an aside, the carbon composite samples appeared to show no
elongation before fracturing during the tensile strength testing while
the mild steel specifications show a 15% elongation before failure.
Also the tensile strength necessary to produce elongation of the mild
steel is 370 MPa. Which illustrates a major difference between carbon
composite and steel. The steel bends or elongates prior to complete
failure while the carbon just breaks.
--
cheers,

John B.


This is fascinating, but I think your first comment was correct -- Tom is either hallucinating or getting smoke blown up his a**. All my CF bikes have lifetime warranties, including an exceptionally light Emonda SLR. My brother flew CF Dreamliners and lived to retirement. The factory making disposable, one-race CF bikes is made-up by someone.

-- Jay Beattie.


Jay - I realize the Trek gives a lifetime warranty on the frameset. And my friend has exercised that three times. Another friend had a Lynskey titanium frame and I warned him to watch for cracks since the material is EXTREMELY sensitive to oxidation in the welding process. He laughed in my face and the very following week I pointed out a crack around the upper headset.


Yup, things break. And with your history of breaking CF forks, I might warn you away from anything CF, even a bottle opener. https://images.bonanzastatic.com/afu...74/s-l1600.jpg If I broke a pair of forks, I might be leading the Grant Peterson anti-CF parade with my wool shako and steel baton. However, after 25 years, I've yet to break a set.


-- Jay Beattie.
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