My Diamondback Bike Almost Killed Me -- Really!

[Vince Mazur]

This is my first time positing to a board, and I want to tell my brief story. April 14th of last
year I was riding my Diamondback Voyager training for the Ride The Rockies Tour. I rode this comfort
mountain bike only on pavement/concrete and am a very conservative rider.

As I was riding along I-25 on the service road and without any hint of warning, the seat post on the
bike snapped like a piece of chalk. I went tumbling toward oncoming traffic on the interstate, but
fortunately stopped short. I thought for sure a rib was lodged in my left lung, but after an
ambulance ride and emergency room treatment, I was sent home with a broken collarbone and severely
bruised ribs. I couldn't lie flat for 8 weeks! I feel very fortunate my life was not taken that day,
but still have a bum left shoulder.

My question to the group: Is a seat post failure such as this common out there?

I am no feather-weight (I weighed about 235 lbs.), but am disgusted that I could be riding straight
and level and just have the seat collapse under me. I thought it long overdue to go public on this
unfortunate event.

Vince

 

[Mike Jacoubowsk]

> As I was riding along I-25 on the service road and without any hint of warning, the seat post on
> the bike snapped like a piece of chalk.

This happened a year ago, I assume you've brought it into a shop since then... what did they say?

Seatposts can fail for a variety of reasons, including being set up too high (not enough left in
the frame), impact (often from being mounted on a roof rack and running into something), an
incorrectly-installed saddle (if it's a failure of the clamping area), etc. The broken parts tell
a tale. In many cases, the time of failure of a components isn't related to when the actual
damage happened.

> My question to the group: Is a seat post failure such as this common out there?

Fortunately, seatpost failures are a rare thing. More common are failures of saddle rails, and
sometimes we'll see a failure of the bolt that holds a seat to the seatpost, but very rarely do we
see a seatpost break in two.

> I am no feather-weight (I weighed about 235 lbs.), but am disgusted that I could be riding
> straight and level and just have the seat collapse under me. I thought it long overdue to go
> public on this unfortunate event.

The issue isn't about "going public" but rather finding out the cause. As I asked earlier, what did
the shop say when it happened? The further you get from the event, the more difficult it becomes to
reconstruct what happened.

--Mike-- Chain Reaction Bicycles www.ChainReaction.com

 

[Gary German]

"Vince Mazur" <[email protected]> wrote in message
news:[email protected]...
> This is my first time positing to a board, and I want to tell my brief story. April 14th of last
> year I was riding my Diamondback Voyager training for the Ride The Rockies Tour. I rode this
> comfort mountain bike only on pavement/concrete and am a very conservative rider.
>
> As I was riding along I-25 on the service road and without any hint of warning, the seat post on
> the bike snapped like a piece of chalk. I went tumbling toward oncoming traffic on the interstate,
> but fortunately stopped short. I thought for sure a rib was lodged in my left lung, but after an
> ambulance ride and emergency room treatment, I was sent home with a broken collarbone and severely
> bruised ribs. I couldn't lie flat for 8 weeks! I feel very fortunate my life was not taken that
> day, but still have a bum left shoulder.
>
> My question to the group: Is a seat post failure such as this common out there?
>
> I am no feather-weight (I weighed about 235 lbs.), but am disgusted that I could be riding
> straight and level and just have the seat collapse under me. I thought it long overdue to go
> public on this unfortunate event.
>
> Vince

Did you purchase it new, or used? If used, I suspect it was abused by its former owner.

Even if you bought it new, that was a pretty low-end bike. The original aluminum seatpost was made
by "Lee Chi" (a Taiwanese manufacturer).

Did you ever inspect the seatpost? Presumably, it didn't just suffer a catastrophic failure if you
were "just riding along". More likely, it had stress fractures that built up over time.

Still, that does kind of suck.

BTW - At your weight, I recommend avoiding anything marketed as "light weight"...it will be more
prone to breakage.

GG

 

[David]

"Vince Mazur" <[email protected]> wrote in message
news:[email protected]...
> My question to the group: Is a seat post failure such as this common out there?

Not *that* common, but it does happen.

> I am no feather-weight (I weighed about 235 lbs.),

I"ve read what the rated rider weight is for most bike parts. I've forgotten the number, but if I
had to guess I'd say 225 lbs. Anyway when you replace your post make sure it's rated for your
weight. Also you might consider a downhill MTB seatpost. Or a steel one. I'm sure lots of 235lb+
riders get away with normal posts. But I'd also imagine you want to be really careful now.

Also make sure you have strong handlebars. I had a cheap stem fail once. It's a very unlikely
failure, but it's to avoided if possible.

David

 

[Patrick O'Grady]

In article <[email protected]>, "David" <[email protected]> wrote:

> "Vince Mazur" <[email protected]> wrote in message
news:[email protected]...
> > My question to the group: Is a seat post failure such as this common out there?
>

I've seen it happen in cyclo-cross, with a much lighter rider. The dude definitely was not enjoying
himself after he leapt back onto the saddle after a barrier only to have the post snap and punch a
hole in his ... well, you get the idea. Lighter is not always better.

Patrick O'Grady Mad Dog Media

 

[Pete Hickey]

In article <[email protected]>, Vince Mazur
<[email protected]> wrote:

>My question to the group: Is a seat post failure such as this common out there?

Funny you ask this. I was thinking about asking it myself (but I was going to ask on
rec.bicycles.tech)

A year of so ago, my son was riding no handed, when his seatpost broke. Fortunately, he only broke
his wrist. I remember Jobst telling a story of a companion of his having a much more serious
accident, (I think while riding without hands as well.)

Now, I like to ride without hands. Is there a way to test a seat post to see if it is about to go?
Is steel the way to go instead of aluminium?

I think I'll crosspost this to rec.bicycles.tech, where the guys hang out who know the answers, and
don't just speculate.

-Pete

--
--
LITTLE KNOWN FACT: Did you know that 90% of North Americans cannot taste the difference between
fried dog and fried cat?

 

[Steve McDonald]

I put my own seat posts together, for just this reason. I take a standard, but extra-long steel
post, ram a one-size smaller steel post inside of that and then put an alder hardwood dowel in the
center. They never would break with this structure and the extra length lets me raise the seat very
high and still have plenty of meat inside the frame. A little extra weight is well-applied here.

Steve McDonald

 

[Gary Jacobson]

I had an Avocet seatpost break under me many years ago. GJ

"Pete Hickey" <[email protected]> wrote in message
news:[email protected]...
> In article <[email protected]>, Vince Mazur
> <[email protected]> wrote:
>
> >My question to the group: Is a seat post failure such as this common out there?
>
> Funny you ask this. I was thinking about asking it myself (but I was going to ask on
> rec.bicycles.tech)
>
> A year of so ago, my son was riding no handed, when his seatpost broke. Fortunately, he only broke
> his wrist. I remember Jobst telling a story of a companion of his having a much more serious
> accident, (I think while riding without hands as well.)
>
> Now, I like to ride without hands. Is there a way to test a seat post to see if it is about to go?
> Is steel the way to go instead of aluminium?
>
> I think I'll crosspost this to rec.bicycles.tech, where the guys hang out who know the answers,
> and don't just speculate.
>
> -Pete
>
> --
> --
> LITTLE KNOWN FACT: Did you know that 90% of North Americans cannot taste the difference between
> fried dog and fried cat?

 

[Jonathan Bond]

Pete Hickey wrote:
> In article <[email protected]>, Vince Mazur
> <[email protected]> wrote:
>
>
>>My question to the group: Is a seat post failure such as this common out there?
>
>
> Funny you ask this. I was thinking about asking it myself (but I was going to ask on
> rec.bicycles.tech)
>
> A year of so ago, my son was riding no handed, when his seatpost broke. Fortunately, he only broke
> his wrist. I remember Jobst telling a story of a companion of his having a much more serious
> accident, (I think while riding without hands as well.)
>
> Now, I like to ride without hands. Is there a way to test a seat post to see if it is about to go?
> Is steel the way to go instead of aluminium?
>
> I think I'll crosspost this to rec.bicycles.tech, where the guys hang out who know the answers,
> and don't just speculate.
>
> -Pete

I've got two words on how to never deal with that again: Thomson Elite.

Jon Bond

 

[Garmonboezia]

[email protected] (Vince Mazur) wrote in news:[email protected]:

> This is my first time positing to a board, and I want to tell my brief story. April 14th of last
> year I was riding my Diamondback Voyager training for the Ride The Rockies Tour. I rode this
> comfort mountain bike only on pavement/concrete and am a very conservative rider.
>
> As I was riding along I-25 on the service road and without any hint of warning, the seat post on
> the bike snapped like a piece of chalk. I went tumbling toward oncoming traffic on the interstate,
> but fortunately stopped short. I thought for sure a rib was lodged in my left lung, but after an
> ambulance ride and emergency room treatment, I was sent home with a broken collarbone and severely
> bruised ribs. I couldn't lie flat for 8 weeks! I feel very fortunate my life was not taken that
> day, but still have a bum left shoulder.
>
> My question to the group: Is a seat post failure such as this common out there?
>
> I am no feather-weight (I weighed about 235 lbs.), but am disgusted that I could be riding
> straight and level and just have the seat collapse under me. I thought it long overdue to go
> public on this unfortunate event.
>
> Vince

Seatpost failure is rare. In fact you're first I've heard of. There are plenty of 200lb+ riders out
there, so I think you're well within the design margin of most bikes.

 

[Luigi De Guzman]

garmonboezia <cthvlhv@r'lyeh.arg> wrote in message news:<sMona.481776$L1.140428@sccrnsc02>...

> Seatpost failure is rare. In fact you're first I've heard of. There are plenty of 200lb+ riders
> out there, so I think you're well within the design margin of most bikes.

Seatposts and stems have a 'minimum insertion line' inscribed on them--you must not raise them
higher than that line, otherwise they will crack...!

I've never experienced a seatpost failure myself--and I'm a big fat ******* at 235 lb/ 18
stone/ 106 kg.

-Luigi

 

[Bob]

"Luigi de Guzman" <[email protected]> wrote in message
news:[email protected]...
> garmonboezia <cthvlhv@r'lyeh.arg> wrote in message
news:<sMona.481776$L1.140428@sccrnsc02>...
>
> > Seatpost failure is rare. In fact you're first I've heard of. There
are
> > plenty of 200lb+ riders out there, so I think you're well within the
design
> > margin of most bikes.
>
> Seatposts and stems have a 'minimum insertion line' inscribed on them--you must not raise them
> higher than that line, otherwise they will crack...!
>
> I've never experienced a seatpost failure myself--and I'm a big fat ******* at 235 lb/ 18
> stone/ 106 kg.
>
> -Luigi

I've always wondered about that little line they slice into the post that says "don't raise above
this line." Aren't they asking for trouble when you raise it above the line? Heck, the weakest point
has to be that line. Personally, my mountain bike has the seat post raised to exactly that line.

--
Bob ctviggen at rcn dot com

 

[David]

"Luigi de Guzman" <[email protected]> wrote in message
news:[email protected]....
>
> Seatposts and stems have a 'minimum insertion line' inscribed on them--you must not raise them
> higher than that line, otherwise they will crack...!

That line isn't about preserving the post, it's about preserving the frame.

 

[Brink]

Failure may be rare, but not unheard of. I am attaching a fantastic site so that you can review any
replacement seatpost that you want to get. The site also has customer reviews of many parts and
bikes. This site should be viewed by all cyclists before purchase of any parts in my opinoin.

http://www.roadbikereview.com/Seatposts/PLS_2510crx.aspx

brink

garmonboezia <cthvlhv@r'lyeh.arg> wrote in message news:<sMona.481776$L1.140428@sccrnsc02>...
> [email protected] (Vince Mazur) wrote in news:[email protected]:
>
> > This is my first time positing to a board, and I want to tell my brief story. April 14th of last
> > year I was riding my Diamondback Voyager training for the Ride The Rockies Tour. I rode this
> > comfort mountain bike only on pavement/concrete and am a very conservative rider.
> >
> > As I was riding along I-25 on the service road and without any hint of warning, the seat post on
> > the bike snapped like a piece of chalk. I went tumbling toward oncoming traffic on the
> > interstate, but fortunately stopped short. I thought for sure a rib was lodged in my left lung,
> > but after an ambulance ride and emergency room treatment, I was sent home with a broken
> > collarbone and severely bruised ribs. I couldn't lie flat for 8 weeks! I feel very fortunate my
> > life was not taken that day, but still have a bum left shoulder.
> >
> > My question to the group: Is a seat post failure such as this common out there?
> >
> > I am no feather-weight (I weighed about 235 lbs.), but am disgusted that I could be riding
> > straight and level and just have the seat collapse under me. I thought it long overdue to go
> > public on this unfortunate event.
> >
> > Vince
>
> Seatpost failure is rare. In fact you're first I've heard of. There are plenty of 200lb+ riders
> out there, so I think you're well within the design margin of most bikes.

 

[Thomas Reynolds]

[email protected] (Vince Mazur) wrote in message
news:<[email protected]>...
> This is my first time positing to a board, and I want to tell my brief .................... taken
> that day, but still have a bum left shoulder.
>
> My question to the group: Is a seat post failure such as this common out there?
>
> I am no feather-weight (I weighed about 235 lbs.), but am disgusted that I could be riding
> straight and level and just have the seat collapse under me. I thought it long overdue to go
> public on this unfortunate event.
>
> Vince

Well I'm happy that you survived. I had a seat post break on January 1, 2002. In my case I wasn't
hurt at all. I was climbing a hill and went to sit down and felt the seat slide out from under me.

I had an aluminum seat post that had a steel insert. It would seem pretty solid but it broke at the
top, where the part that mounts the seat is welded to the post itself. Specifically, the weld broke.

After getting some good info from this group I purchased a Thomson Elite forged (no welds) 7075
aluminum seatpost.

Tom

 

[Hunrobe]

>[email protected] (Steve McDonald)

wrote:

>
> I put my own seat posts together, for just this reason. I take a standard, but extra-long
> steel post, ram a one-size smaller steel post inside of that and then put an alder hardwood
> dowel in the center. They never would break with this structure and the extra length lets me
> raise the seat very high and still have plenty of meat inside the frame. A little extra weight
> is well-applied here.

I'm almost afraid to ask how you "protect" against flat tires, pedal pullout, or chain skip. Are
you the guy I see riding his three speed occasionally? He's always wearing a full coverage
motorcycle helmet and what appears to be a padded suit of chain mail. Sure, it's a little extra
weight but......

Regards, Bob Hunt