Physics lesson

John B. wrote:
On Sun, 11 May 2014 23:17:02 -0700 (PDT), Dan O
wrote:

On Sunday, May 11, 2014 10:41:17 AM UTC-7, Dan O wrote:
On Friday, May 9, 2014 4:25:38 PM UTC-7, jbeattie wrote:

snip

http://www.channel3000.com/news/bicy...ident/25893480

Hmm... Shaina doesn't say she witnessed the crash - just that it's
out in front of her apartment.


More comments: "we saw it happen. no red light at that intersection,
no cones warning cyclists of the giant crack in the road"

Still not definitive, but "giant crack" sounds more like a fork
breaker than a front wheel grabber.

Is the implication here that a bicyclist requires some sort of notice
about road conditions? After all, a "construction zone" is sort of
under construction and one might expect somewhat less then pristine
road conditions.

--
Cheers,


Sometime the whole city is a construction zone. Two cyclists in recent
weeks hit by flatbread trucks used to transport cranes. Two separate
incidents. One dead and one critical.

We have cracks in roads bad enough to take down cyclists without any
construction zone.



--
duane

On 5/12/2014 5:54 AM, John B. wrote:
On Sun, 11 May 2014 23:17:02 -0700 (PDT), Dan O
wrote:

On Sunday, May 11, 2014 10:41:17 AM UTC-7, Dan O wrote:
On Friday, May 9, 2014 4:25:38 PM UTC-7, jbeattie wrote:

snip

http://www.channel3000.com/news/bicy...ident/25893480

Hmm... Shaina doesn't say she witnessed the crash - just that it's
out in front of her apartment.


More comments: "we saw it happen. no red light at that intersection,
no cones warning cyclists of the giant crack in the road"

Still not definitive, but "giant crack" sounds more like a fork
breaker than a front wheel grabber.

Is the implication here that a bicyclist requires some sort of notice
about road conditions? After all, a "construction zone" is sort of
under construction and one might expect somewhat less then pristine
road conditions.


OK I'm with you generally. On to specifics.

Except in 2014 E Johnson, a major one-way arterial, is
pocked so badly the the orange cones start by my friend's
house at 100 east and goes all the way out to 1400 east with
traffic pinched to one lane. The usual pace of road repairs
inches along. There are deep utility trenches, not so deep
slits, piles of materials, various equipment and general
obstruction beyond the cones.

I wouldn't tell a cyclist where or how to ride but my choice
of route is parallel on a paved street.

This is a file photo not actually Johnson street:
http://madisoneast.channel3000.com/n...reconstruction

This shows the area:
http://www.cityofmadison.com/enginee...johnsonMap.jpg

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

On 5/12/2014 7:09 AM, Duane wrote:

Sometime the whole city is a construction zone. Two cyclists in recent
weeks hit by flatbread trucks used to transport cranes. Two separate
incidents. One dead and one critical.

How did those crashes happen?


--
- Frank Krygowski

On 5/9/2014 4:25 PM, jbeattie wrote:

snip

The comment by police that the broken fork caused the accident is very typical. Riders have wall impacts or catch a stick in their forks, get ejected and wake to find a broken CF fork. As a result of head injury or poor reasoning skills, they immediately conclude that the broken fork caused their fall. In the course of representing manufacturers, I have seen very few forks of any design that simply fell apart during normal use. It happens, but it is very rare.

They fail a lot but it's usually a latent defect or a design issue that
doesn't become apparent until the fork is stressed. So while it isn't
accurate to say that the broken fork cause the crash it's probably
accurate to say that the rough road caused the broken fork. He would
likely have crashed even if the fork hadn't broken if the wheel got
caught in a crack in the pavement. If he just hit a bump and the fork
broke as a result (which is common with CF forks) then that's another story.

CF doesn't require a very high force to cause a failure, and you get
fatigue from relatively low forces. There's a good article about carbon
fiber forks he
https://web.archive.org/web/20100531033826/http://www.rivbike.com/products/show/carbonoms-fork/50-718.
Unfortunately the replacement program has ended.

On Monday, May 12, 2014 11:46:33 AM UTC-4, sms wrote:
On 5/9/2014 4:25 PM, jbeattie wrote:



snip



The comment by police that the broken fork caused the accident is very typical. Riders have wall impacts or catch a stick in their forks, get ejected and wake to find a broken CF fork. As a result of head injury or poor reasoning skills, they immediately conclude that the broken fork caused their fall. In the course of representing manufacturers, I have seen very few forks of any design that simply fell apart during normal use. It happens, but it is very rare.



They fail a lot but it's usually a latent defect or a design issue that

doesn't become apparent until the fork is stressed. So while it isn't

accurate to say that the broken fork cause the crash it's probably

accurate to say that the rough road caused the broken fork. He would

likely have crashed even if the fork hadn't broken if the wheel got

caught in a crack in the pavement. If he just hit a bump and the fork

broke as a result (which is common with CF forks) then that's another story.



CF doesn't require a very high force to cause a failure, and you get

fatigue from relatively low forces. There's a good article about carbon

fiber forks he

https://web.archive.org/web/20100531033826/http://www.rivbike.com/products/show/carbonoms-fork/50-718.

Unfortunately the replacement program has ended.

More rubbish. What planet did you come from anyway?

Cheers

On Monday, May 12, 2014 3:54:41 AM UTC-7, John B. wrote:
On Sun, 11 May 2014 23:17:02 -0700 (PDT), Dan O wrote:
On Sunday, May 11, 2014 10:41:17 AM UTC-7, Dan O wrote:
On Friday, May 9, 2014 4:25:38 PM UTC-7, jbeattie wrote:

http://www.channel3000.com/news/bicy...ident/25893480


Hmm... Shaina doesn't say she witnessed the crash - just that it's
out in front of her apartment.


More comments: "we saw it happen. no red light at that intersection,
no cones warning cyclists of the giant crack in the road"

Still not definitive, but "giant crack" sounds more like a fork
breaker than a front wheel grabber.

Is the implication here that a bicyclist requires some sort of notice
about road conditions?

I believe that was implied by the commenter I quoted. I was
not endorsing their views in any way, shape, or form - just
taking clues from the eyewitness account for my little game
of "best guess" CSI. The commenter actually goes on to say
something like "the rider did nothing wrong except not wear
a helmet" :-) (I must say I wish I had better sources of
information for even the objective stuff I'm trying to glean
for my little guessing game.)

After all, a "construction zone" is sort of
under construction and one might expect somewhat less then pristine
road conditions.

I said earlier, "Surely it was what the rider did that put
the fork into such a predicament."

As and aside, I note the usual vitriol and vehement animosity -
all out of any semblance of proportion - toward bicyclists, along
with ample remarks like, "the kind of biker who gives all the
others a bad reputation" (which is just stupid).

sms wrote:
On 5/9/2014 4:25 PM, jbeattie wrote:

snip

The comment by police that the broken fork caused the accident is very
typical. Riders have wall impacts or catch a stick in their forks, get
ejected and wake to find a broken CF fork. As a result of head injury
or poor reasoning skills, they immediately conclude that the broken fork
caused their fall. In the course of representing manufacturers, I have
seen very few forks of any design that simply fell apart during normal
use. It happens, but it is very rare.

They fail a lot but it's usually a latent defect or a design issue that
doesn't become apparent until the fork is stressed. So while it isn't
accurate to say that the broken fork cause the crash it's probably
accurate to say that the rough road caused the broken fork. He would
likely have crashed even if the fork hadn't broken if the wheel got
caught in a crack in the pavement. If he just hit a bump and the fork
broke as a result (which is common with CF forks) then that's another story.

CF doesn't require a very high force to cause a failure, and you get
fatigue from relatively low forces. There's a good article about carbon
fiber forks he
e: https://web.archive.org/web/20100531033826/http://www.rivbike.com/products/show/carbonoms-fork/50-718.
Unfortunately the replacement program has ended.

You stick to steel I keep using my CF ones.

--
Lou

On Monday, May 12, 2014 8:46:33 AM UTC-7, sms wrote:
On 5/9/2014 4:25 PM, jbeattie wrote:



snip



The comment by police that the broken fork caused the accident is very typical. Riders have wall impacts or catch a stick in their forks, get ejected and wake to find a broken CF fork. As a result of head injury or poor reasoning skills, they immediately conclude that the broken fork caused their fall. In the course of representing manufacturers, I have seen very few forks of any design that simply fell apart during normal use. It happens, but it is very rare.



They fail a lot but it's usually a latent defect or a design issue that

doesn't become apparent until the fork is stressed. So while it isn't

accurate to say that the broken fork cause the crash it's probably

accurate to say that the rough road caused the broken fork. He would

likely have crashed even if the fork hadn't broken if the wheel got

caught in a crack in the pavement. If he just hit a bump and the fork

broke as a result (which is common with CF forks) then that's another story.



CF doesn't require a very high force to cause a failure, and you get

fatigue from relatively low forces. There's a good article about carbon

fiber forks he

https://web.archive.org/web/20100531033826/http://www.rivbike.com/products/show/carbonoms-fork/50-718.

Unfortunately the replacement program has ended.

So Steve, on what do you base your comment that CF forks fail "a lot." I get the sense that they don't fail a lot in Oregon, because I've only defended a couple CF fork cases, and I represent some big manufacturers state-wide. My last CF fork failure involved a dog leash getting wrapped up in the wheel (avoid MUPs). The forks were a casualty and not the cause of the fall. If there is an epidemic, it's not reached my desk.

-- Jay Beattie.

On 5/12/2014 12:23 PM, jbeattie wrote:
On Monday, May 12, 2014 8:46:33 AM UTC-7, sms wrote:
On 5/9/2014 4:25 PM, jbeattie wrote:



snip



The comment by police that the broken fork caused the accident is very typical. Riders have wall impacts or catch a stick in their forks, get ejected and wake to find a broken CF fork. As a result of head injury or poor reasoning skills, they immediately conclude that the broken fork caused their fall. In the course of representing manufacturers, I have seen very few forks of any design that simply fell apart during normal use. It happens, but it is very rare.



They fail a lot but it's usually a latent defect or a design issue that

doesn't become apparent until the fork is stressed. So while it isn't

accurate to say that the broken fork cause the crash it's probably

accurate to say that the rough road caused the broken fork. He would

likely have crashed even if the fork hadn't broken if the wheel got

caught in a crack in the pavement. If he just hit a bump and the fork

broke as a result (which is common with CF forks) then that's another story.



CF doesn't require a very high force to cause a failure, and you get

fatigue from relatively low forces. There's a good article about carbon

fiber forks he

https://web.archive.org/web/20100531033826/http://www.rivbike.com/products/show/carbonoms-fork/50-718.

Unfortunately the replacement program has ended.

So Steve, on what do you base your comment that CF forks fail "a lot." I get the sense that they don't fail a lot in Oregon, because I've only defended a couple CF fork cases, and I represent some big manufacturers state-wide. My last CF fork failure involved a dog leash getting wrapped up in the wheel (avoid MUPs). The forks were a casualty and not the cause of the fall. If there is an epidemic, it's not reached my desk.

-- Jay Beattie.


Indeed we don't see broken carbon forks in service much,
especially given their ubiquitous nature on modern bikes. Of
the failures, something-in-wheel is the primary cause,
accounting for virtually all cracked carbon blades:
http://www.yellowjersey.org/photosfromthepast/CRASH.JPG

If there's an epidemic it's well hidden.

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

On 5/12/2014 1:54 PM, AMuzi wrote:
On 5/12/2014 12:23 PM, jbeattie wrote:
On Monday, May 12, 2014 8:46:33 AM UTC-7, sms wrote:
On 5/9/2014 4:25 PM, jbeattie wrote:



snip



The comment by police that the broken fork caused the accident is
very typical. Riders have wall impacts or catch a stick in their
forks, get ejected and wake to find a broken CF fork. As a result
of head injury or poor reasoning skills, they immediately conclude
that the broken fork caused their fall. In the course of
representing manufacturers, I have seen very few forks of any design
that simply fell apart during normal use. It happens, but it is
very rare.



They fail a lot but it's usually a latent defect or a design issue that

doesn't become apparent until the fork is stressed. So while it isn't

accurate to say that the broken fork cause the crash it's probably

accurate to say that the rough road caused the broken fork. He would

likely have crashed even if the fork hadn't broken if the wheel got

caught in a crack in the pavement. If he just hit a bump and the fork

broke as a result (which is common with CF forks) then that's another
story.



CF doesn't require a very high force to cause a failure, and you get

fatigue from relatively low forces. There's a good article about carbon

fiber forks he

https://web.archive.org/web/20100531033826/http://www.rivbike.com/products/show/carbonoms-fork/50-718.


Unfortunately the replacement program has ended.

So Steve, on what do you base your comment that CF forks fail "a
lot." I get the sense that they don't fail a lot in Oregon, because
I've only defended a couple CF fork cases, and I represent some big
manufacturers state-wide. My last CF fork failure involved a dog leash
getting wrapped up in the wheel (avoid MUPs). The forks were a
casualty and not the cause of the fall. If there is an epidemic, it's
not reached my desk.

-- Jay Beattie.


Indeed we don't see broken carbon forks in service much, especially
given their ubiquitous nature on modern bikes. Of the failures,
something-in-wheel is the primary cause, accounting for virtually all
cracked carbon blades:
http://www.yellowjersey.org/photosfromthepast/CRASH.JPG


"Something in wheel" is probably the primary cause for AL forks as well
wouldn't you say?

If there's an epidemic it's well hidden.


I keep asking where all the bodies are hidden ...