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Old December 27th 18, 01:22 AM posted to rec.bicycles.tech
John B. Slocomb
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Default Interesting track crashes

On Wed, 26 Dec 2018 12:02:58 -0800 (PST), wrote:

On Thursday, November 29, 2018 at 1:25:28 PM UTC-8, Sir Ridesalot wrote:
An interesting video of track bicycles crashing. Amazing what happens when a tubular tire comes off the rim. I was surprised at how long one rider stayed up - he was okay until the front tire went under his rear wheel.

I saw bits flying around in some of the crashes but couldn't make out what those bits were.

https://www.youtube.com/watch?v=tf17hFikqrQ

Cheers


Track tubulars are paper thin so flats from overheating aren't all that uncommon. My friend who has turned into a total anti-carbon fiber nut sent me a video link to a subject he called "carbon fiber rim exploding under track rider." That isn't what I would have called it. If you look at it closely it looks like a track tandem gets a flat in the final sprint which throws the entire weight of the team unto the front disk which slowly comes apart as the tire peels off.

I showed him that foregoing manufacturing errors that all of the bicycle materials have approximately the same loaded lifespan. That was sort of surprising to me since I have a lot of steel bikes and never had a failure. But I suppose I usually buy them with very little use and they simply don't have that many miles.

Actually the most common frame material to fail is aluminum. Come sources say never keep an aluminum frame for more than 10 years max. And the failures are highly reminiscent of the Internet pictures of carbon fiber failures save that the CF bikes usually have been hit by cars whereas the AL bikes simply fall apart.


Interesting.
Of course Sheldon Brown, that sneaky devil, describes a study
conducted by EFBe (Engineering for Bikes) which is now, I believe, one
of the main elements of the DIN 79100 bicycle-testing standard, which
was published in TOUR magazine of Oct 1997 ( more then 20 years ago)
that demonstrated that two of the three frames that completed the test
with no failures were welded aluminum frames. Two out of three... lets
see, that is about 66.666 %, isn't it?

The Christian Bible has a phrase that seems to apply here (Proverbs
17:28. New International Version)

"Even a fool is thought wise if he keeps silent, and discerning if he
holds his tongue."

cheers,

John B.


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