Post-recall R-Sys wheel failure

On Jun 9, 8:04*pm, "Mike Jacoubowsky" wrote:
"Robert Chung" wrote in message

...

Mike Jacoubowsky wrote:

Perhaps. But one of the most-interesting things about this is that it
was in VeloNews, a publication that Mavic advertises in pretty
heavily

Dumbass,

It happened to the Editor in Chief for Velonews. Think if it'd
happened to one of us (same circumstances same witnesses same article)
they'd've published it?

The Editor in Chief, of all people, is made sensitive to the needs of
advertisers. More likely to see that sort of thing come out from a
less-senior staff member, and then an editor gets in all manner of
trouble for allowing it to be printed.

My guess is that Mavic made a monumental error in even suggesting the
possibility that the rider may have been at fault. That probably set him
off. Even if it's possible the rider *was* somehow responsible, that
sort of thing has to be handled very carefully when the rider has, well,
teeth. And the Editor of a cycling publication has teeth.

--Mike Jacoubowsky
Chain Reaction Bicycleswww.ChainReaction.com
Redwood City & Los Altos, CA USA

"Robert Chung" wrote in message

...

Mike Jacoubowsky wrote:

Perhaps. But one of the most-interesting things about this is that it
was in VeloNews, a publication that Mavic advertises in pretty
heavily

Dumbass,

It happened to the Editor in Chief for Velonews. Think if it'd
happened to one of us (same circumstances same witnesses same article)
they'd've published it?

Nothing 'set him off'(being in Boulder and knowing a lot of these guys
has it's advantages). Two 'teams' met, represented by lawyers on both
sides, calm discussions ensued at the site, with the wheel and
bicycle, another in a conference room. Mavic just doesn't seem
interested in taking any responsibility here(my opinion). I am sure
this issue went up and down at Velonews considering the plus and
minuses of writing this. I think rider safety is an issue that
Velonews couldn't ignore.

On Wed, 10 Jun 2009 11:01:28 +0200, Donald Munro
wrote:

I don't see the point anyway - I doubt if they're much lighter than
Sapim CX-ray or DT Revolution spokes. Didn't these R-Sys wheels test
as the least aerodynamic wheel from a large range of wheels a while
back ? Any minimal weight gain would probably be cancelled out by
the aero drag.

The no-spoke wheels were reportedly heavier than typical spoked
wheels, so in typical rbr logic, we can argue that the fewer the
spokes, the heavier the wheel.

Doubt the no-spoke wheels (I saw an operational set at a LAW or LAB
meeting and I kind of remember them being two rims, with one rotating
on the set, suspended one - changing the ball bearings would be a
bear) were particularly aero or anything, but it was cool looking.
Better than the skate wheels as bike wheels that AFAIK came and
disappeared with nary a ripple in the cycling or rbr world. Think
someone sent the inventor down a San Francisco road that had ruts...

Curtis L. Russell
Odenton, MD (USA)
Just someone on two wheels...

On Tue, 9 Jun 2009 16:19:47 -0700, "Tom Kunich" cyclintom@yahoo. com
wrote:

Steel bends while carbon breaks. Total failure of both frame materials is
about the same these days but the steel frame tends to fail in a manner that
throws you sideways while carbon failures puts you face first into the
ground. Ain't much fun.

I'm guessing frame tendencies are far from a primary cause of how your
bike falls. If you are over the handlebars when it fails, you'll have
a nose like mine. FWIW, I haven't had enough carbon long enough to
know about frame failures, but half of my steel frame failures before
accidents were nasty looking separations, with lots of jokes about
what would of been if I had inthe wrong place at the wrong time. Two
were the traditional bent bar version.

I will take responsibility for the painted frame - I ignored signs of
internal damage. The damned chrome frame from hell (lots of issues
with that one) kept the damage to itself IMO and snapped when it made
its mind up to do so. Top tube and it was very pointy after snapping.
Very little frame stability with a two piece top tube.

There were lots of rumors of how nasty carbon was and you could see
the signs when you saw a frame that had shattered. OTOH, I don't
recall a single incident that resulted in someone headed to ER from
anything spectacular in a race or training ride. The closest was a
couple of carbon rims, and that was when the husband drove his wife's
wheels into a parking lot height control thing and shattered them a
couple of minutes before her race. That had all the signs of becoming
very bloody, but he wouldn't leave the car during the 'discussion', so
he came out OK.

Curtis L. Russell
Odenton, MD (USA)
Just someone on two wheels...

On Tue, 09 Jun 2009 21:34:02 -0700, Fred Fredburger
wrote:

At the other end of the spectrum there's Bicycling, which exists solely
to provide ad space. Who takes that magazine seriously?

With every sign they use their agreements with bicycling organizations
to pump subscription numbers (fact) and misreport them as paid or
requested subscriptions (rumor, but from someone that was tracking
numbers).

Curtis L. Russell
Odenton, MD (USA)
Just someone on two wheels...

On Tue, 09 Jun 2009 19:58:53 -0700, Michael Press
wrote:

In article ,
"Robert Chung" wrote:

http://www.velonews.com/article/9305...-wheel-failure

Appears to have suffered brain damage as a result of that little mishap.

Read for content. The aluminum can analogy clearly shows he is a
candidate for the Livedrunk(C) group.

And aluminum cans ARE safer. Back in the day, when steel cans and
aluminum cans were both about, I saw a guy slam a steel can against
his forehead, intending to crush it. I think he is a track racer
today...

Curtis L. Russell
Odenton, MD (USA)
Just someone on two wheels...

Fred Fredburger wrote:
At the other end of the spectrum there's Bicycling, which exists solely
to provide ad space. Who takes that magazine seriously?

I subscribe to our local dead tree newspaper only because my
wife wants to get the advertising circulars. They have a
relationship with the local chamber of commerce that I might
describe in colorful terms but won't because I know many
here have delicate sensibilities.

There are times when I don't take them seriously. But I do
understand that traditional media is under financial pressure.

Bob Schwartz

Fred Fredburger wrote:
At the other end of the spectrum there's Bicycling, which exists solely
to provide ad space. Who takes that magazine seriously?

Bob Schwartz wrote:
I subscribe to our local dead tree newspaper only because my wife wants
to get the advertising circulars. They have a relationship with the
local chamber of commerce that I might describe in colorful terms but
won't because I know many here have delicate sensibilities.

I have ****ing delicate sensibilities.

"Mike Jacoubowsky" wrote in message
...

Since down tubes act in tension a buckled down tube is not
the proximate cause of failure. How did those frames fail
that had buckled down tubes?

Frontal impact. Steel frames & forks were typically not very strong in
such situations. You and I may be interpreting this thread differently; I
am not talking about JRA (Just Riding Along) failures.

Try hitting a dog while going 20 mph. A well known and expensive carbon bike
head tube broke off like it was paper mache'. A steel bike wouldn't fail
that way.

Tom Kunich wrote:


Try hitting a dog while going 20 mph.

No Thanks. I'd avoid that.

A well known and expensive carbon
bike head tube broke off like it was paper mache'. A steel bike wouldn't
fail that way.


Carbon Frames are fully endorsed by PETA for causing animals less damage
when hit by a bicycle.

not unlike automobiles that are made to crumple in a certain way to
provide better safety.


Bill


--
William R. Mattil

http://www.celestial-images.com

On Jun 9, 12:16*pm, "Robert Chung"
wrote:
http://www.velonews.com/article/9305...rience---a-pos...

I saw this the other day, and went to Mavic's page to look at the
details on the "Trancomp" technology, where the tubular carbon spokes
support loads in both tension and compression. The videos are
interesting to watch, as the tubular CF spokes are quite amazing in
their ability to support significant compressive loads. That said, I
can't see much advantage from these wheels, and their reliability
under real-world conditions doesn't look impressive. They appear to be
about the same weight as steel-spoked wheels of similar spoke count
(e.g. Easton EA90 SLX @1398 gm with skewers vs 1350 gm for standard R-
Sys wheels), have poorer aerodynamics (due to fat, round CF spokes),
are more expensive, and are more complex to service (assuming the
wheel doesn't completely explode when a spoke lets go). The only
positive I see for these wheels is a claim of higher stiffness, but I
haven't seen any comparative data.

In the case that was cited, it may be that transitioning over the
crown of the road, or hitting some other road imperfection or debris
subjected the rim to enough lateral force such that the compressed
carbon spoke exceeded its ability to handle the side load and
collapsed. Given the low spoke count it may be that it only takes one
spoke to fail for the wheel to lose its structural integrity and to
collapse. It would be interesting to compare the ability of such
wheels to withstand a spoke falure to wheels that depend solely on
tension, I suspect that highly tensioned wheels are more resistant to
collapse in the event of a spoke failure.

Brad Anders