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Old 05-27-08, 08:22 PM   #1
sadams
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Alexrim AT450 broken spokes

My 10 year old son had a bad accident today while riding his 4 month old Trek 1.2 bike with Alexrim AT450 wheels. We were going about 15mph and I heard a loud noise and witnessed him do a flip over the handle bars and land on his head and then bounce a few more times on the pavement. It appears a few of the front spokes broke and locked up the wheel causing him to flip. He might have a broken foot and a bruised chest and thank God the helmut worked flawlessly. Luckily we just got off the main road when the accident happened or the end result could have been tragic. I believe this is VERY SERIOUS product problem and I'm going to contact the bike shop in the morning to inquire about getting this reported to the manufactor(s). I wanted to post my story to see if anyone else has experienced similar problems and/or to serve as a warning to others using similar equipment.
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Old 05-27-08, 08:44 PM   #2
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I can only find one reference to broken spokes in relation to an AT450 rim, and not a single complaint in regards to the Trek 1.2 ever suffering such an issue.

Are you sure (and don't let your emotions get in the way of your answer - think it out calmly and rationally) that the cause of the accident (and the broken front spokes) might have been as a result of your son jamming the front brake on? How long has your son been riding bikes equipped with dual-pivot brakes or V-brakes?

Were there any branch or tube/pipe/object that might have jammed between the spokes and front fork nearby?

For that matter, you said you heard a loud sound, but did not specify what the sound was from, or when it happened. May I inquire as to whether the front tire remained inflated or was it deflated after the accident?

I find it most unusual that a whole series of spokes broke at once. One broken spoke alone would have bent out of the way and scratched the fork. It would take at the least, two or three spokes in strategic locations to jam up that front wheel. Seems to me that there is more here then meets the eye.

Take care,

-Kurt

P.S.: I'm still leaning towards the idea that he slammed on the front brake too hard. It would be human nature for a 10 year old not to admit his fault in doing so for fear of being reprimanded (and for that matter, it is a rare person that will admit fault as opposed to blame a happening on someone else).

P.S. #2: The bike shop is not the place for you to vent your complaint about the product. Concern about it and warranty replacement components, yes, but if you have a beef with the product itself (remember, the bike shop does not manufacture those spokes or the wheel), your venue is www.trekbikes.com.
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Old 05-28-08, 09:33 AM   #3
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Other things to consider are: a squirrel tried to jump threw the front wheel (not that uncommon) or somehow a stick flipped into the wheel (that has happened to me a couple of times with my back wheel.)
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Old 05-28-08, 10:29 AM   #4
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Could you post pictures of the broken spokes, and any other damaged parts (Trek will also want pictures). Did any of the spokes pull out of the rim? Hope your son recovers soon.
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Old 05-28-08, 10:49 AM   #5
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Quote:
Originally Posted by sadams View Post
thank God the helmut worked flawlessly.
Send some love to the manufacturers of the helmet as well. I used to make body armor for the troops and what made it so rewarding wasn't the minuscule pay or long hours, it was knowing that my job was having an impact and saving lives.
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Old 05-29-08, 04:47 AM   #6
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I really don't think he jammed on his brakes because I was 5 ft in front of him and I heard the loud noise (not the sound of braking) before he fell. There was nothing on the road and the surface was flat and clear. Also, both tires are fully inflated. Also, we typically go on 10 - 20 miles and he knows how to control the bike and use the brakes.

Did you read a similar post from 2004 which describes practically the same thing happening ? However, this doesn't appear to be a widespread problem because there would be more chatter out there on this subject.

My goal is to make sure this gets some technical and engineering attention to find out why and how this happened. I called the bike shop already and told them what happened. They asked me to bring in the bike and they were going to put me in touch with the Trek rep.

I'll post a few pictures later that show 3 spokes separated from the rim.



Quote:
Originally Posted by cudak888 View Post
I can only find one reference to broken spokes in relation to an AT450 rim, and not a single complaint in regards to the Trek 1.2 ever suffering such an issue.

Are you sure (and don't let your emotions get in the way of your answer - think it out calmly and rationally) that the cause of the accident (and the broken front spokes) might have been as a result of your son jamming the front brake on? How long has your son been riding bikes equipped with dual-pivot brakes or V-brakes?

Were there any branch or tube/pipe/object that might have jammed between the spokes and front fork nearby?

For that matter, you said you heard a loud sound, but did not specify what the sound was from, or when it happened. May I inquire as to whether the front tire remained inflated or was it deflated after the accident?

I find it most unusual that a whole series of spokes broke at once. One broken spoke alone would have bent out of the way and scratched the fork. It would take at the least, two or three spokes in strategic locations to jam up that front wheel. Seems to me that there is more here then meets the eye.

Take care,

-Kurt

P.S.: I'm still leaning towards the idea that he slammed on the front brake too hard. It would be human nature for a 10 year old not to admit his fault in doing so for fear of being reprimanded (and for that matter, it is a rare person that will admit fault as opposed to blame a happening on someone else).

P.S. #2: The bike shop is not the place for you to vent your complaint about the product. Concern about it and warranty replacement components, yes, but if you have a beef with the product itself (remember, the bike shop does not manufacture those spokes or the wheel), your venue is www.trekbikes.com.

Last edited by sadams; 05-29-08 at 04:59 AM. Reason: corrections
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Old 05-29-08, 11:03 AM   #7
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The spoke breakage could have permitted the rim to taco and jam against the brake causing the header. If something had caught in the spokes I would expect a bent spoke and corresponding paint damage on the fork. Did the spokes break at the nipples or did the nipples pull through the rim?
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Old 05-29-08, 05:39 PM   #8
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Quote:
Originally Posted by AndrewP View Post
The spoke breakage could have permitted the rim to taco and jam against the brake
Bend, you mean - not taco. The tube, supposedly, has remained inflated throughout the entire ordeal, so the rim could not have bent up upon itself.

-Kurt

P.S.: Mods, wouldn't this be better served in Bicycle Mechanics?
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Old 05-29-08, 05:42 PM   #9
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I really don't think he jammed on his brakes because I was 5 ft in front of him and I heard the loud noise (not the sound of braking) before he fell.
10-4. What type of a sound was it that you heard?

Quote:
Originally Posted by sadams View Post
Did you read a similar post from 2004 which describes practically the same thing happening ? However, this doesn't appear to be a widespread problem because there would be more chatter out there on this subject.
No, I did not see it. Would appreciate a link to the topic you speak of. When did you happen to locate that archived thread, incidentally?

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My goal is to make sure this gets some technical and engineering attention to find out why and how this happened. I called the bike shop already and told them what happened. They asked me to bring in the bike and they were going to put me in touch with the Trek rep.
Reasonable enough.

-Kurt
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Old 05-29-08, 07:09 PM   #10
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It was a loud popping sound as you would imagine spokes being pulled through the rim. One of the prior posts listed below describes the same thing happening to him and he later makes a correction that he was using the same AT450 rim.

Here are two prior posts:
Broken spokes
http://www.bikeforums.net/showthread...ighlight=at450
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Old 05-29-08, 07:11 PM   #11
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The nipples pulled through the rim and I'll post some pictures once I figure out how to reduce the file size

Quote:
Originally Posted by AndrewP View Post
The spoke breakage could have permitted the rim to taco and jam against the brake causing the header. If something had caught in the spokes I would expect a bent spoke and corresponding paint damage on the fork. Did the spokes break at the nipples or did the nipples pull through the rim?
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Old 05-29-08, 08:35 PM   #12
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The nipples pulled through the rim and I'll post some pictures once I figure out how to reduce the file size
Pulled through the rim? Very interesting - pics are a must. Sounds as if stress cracks developed around the non-eyeleted drillings in the rim until one spoke failed and caused a chain reaction amongst the others.

Question is whether these stress cracks were a result of a bad rim design or over-tightening of the nipples from factory.

Irfanview.com - download their image editor, then resize the photo and adjust .jpg compression when you re-save it.

-Kurt
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Old 06-01-08, 01:50 PM   #13
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pics

Here are two pics of the broken spokes and I hope this works.
Attached Images
File Type: jpg IMG_1019.jpg (78.8 KB, 37 views)
File Type: jpg IMG_1024.jpg (87.8 KB, 37 views)
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Old 06-04-08, 11:05 PM   #14
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The rim is fine - the spoke nipples (the "nuts" at the end of the spoke) broke off at the head. Could be either defective spoke nipples (manufacturing defect), or a lack of lubrication combined with factory overtightening. I'd put a guess to the former.

-Kurt
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Old 09-08-11, 03:54 AM   #15
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broken spoke

This is a reply to an old post but I recently had a similar event myself i.e. AlexRims w/ black spokes / front wheel broken spoke mid-way / spoke jammed in fork (or possibly jammed in bike computer magnetric sensor attachment on fork) / rider carries forward onto head etc.

I try to keep an open mind but am really quite convinced that the spoke caused the accident, and this was the independent opinions of the amulance crew and a bike shop mechanic too.

I can try to describe the broken spoke. The part attached to the rim was loose but completely straight. The break seems to be clean, that is: it looks as it would had wire cutters been used. The half that got stuck in the fork was bent back over itself several times - really quite mangled.

For those interested in the technicalities: Specialised Secteur bike somewhat in need of general servicing after 350 recent miles in Switerzland (and thank goodness it didn't break on any of those decents), size 58

Last edited by MountainMan4; 09-08-11 at 03:57 AM.
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