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  1. #1
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    Thomson Seatpost Broke today

    I'm OK, which is the main thing. Seriously, if I had not been riding on smooth concrete, this would have been a compete disaster. Added help was that I have a small Cannondale seatbag for a spare tube under my seat with small velcro loop that goes around the post in addition to the seat rails. That's the only thing that saved me from an aluminun colonoscopy. I have 5 Thomson seatposts and never had an issue with any of them till today. Across those posts I have over 100,000 care free miles. Owned this particular post 10 months and about 2000 miles. It's a Thomson Setback 31.6 410mm I have been using in Cannondale Caffeine framesets. The post has never been dropped, wrecked, knock over or even put in a repair stand.

    Frankly I did not think this was possible because I read that the bolts are supposed to break before the seatpost. I have not even heard of a Thomson failure before.






  2. #2
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    That really sucks. Call them and they'll take care of you.

  3. #3
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    Wow, that sucks. Although, not everyone can brag about breaking a Thomson, so at least you have that much going for you.

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    I'm guessing they will be very concerned, send you a new one, and ask for the broken one for analysis

  5. #5
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    Ever hit a garage?

  6. #6
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    Quote Originally Posted by Jerk_Chicken
    Ever hit a garage?
    'Zakly what I was thinking .

  7. #7
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    Quote Originally Posted by Jerk_Chicken
    Ever hit a garage?
    Nope. Don't even own a roof rack. Don't even own a garage.

    Had to ride 18 miles home standing. That gets a little old after awhile. But not too bad. The weather was nice and I had the wind at my back.

  8. #8
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    Quote Originally Posted by apacherider
    Nope. Don't even own a roof rack. Don't even own a garage.

    Had to ride 18 miles home standing. That gets a little old after awhile. But not too bad. The weather was nice and I had the wind at my back.
    Wow, that is just nuts...looks like something absolutely catastrophic happened there. 18mi...no cell phone? I called the wife today to come and rescue me with the truck because I flatted on the road bike a 2nd time 15 miles from home, grrr.

  9. #9
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    Is this even common for any kind of kind of seat post, including non name brands? Just thinking about the potential injury from taking that up the rear is disturbing.

  10. #10
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    Now I've seen it all.

  11. #11
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    Maybe it was a manufacturing defect that took 2k miles to finally break?

  12. #12
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    Any chance of getting a macro close up of the cross section on both ends? I'd love to see a close up of the damage.

    I had a post fail on me on the trainer. But the funny part was that I was on the trainer b/c I had a broken collar bone so I couldn't use my arm/ride outside.

    When the post broke, I collapsed to the floor banging my arm/shoulder into pretty much everything, that really hurt. But kinda funny now....

  13. #13
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    Quote Originally Posted by civil
    Any chance of getting a macro close up of the cross section on both ends? I'd love to see a close up of the damage.



    That's about as good a photo as I can get with my crummy camera. I know nothing about metal or fatigue. The front side is the clean break side, the rear is the jagged side. From what I understand, the seatpost has an elliptical build to it with more material on the front/back rather than the sides. Does it look like the rear end lacks some material or is that just a result of the deforming when it broke?

    In the photo below, see all the little teeny tiny fractures? They are on the rear facing side of the seat post. I don't know if they occured over time and I did not notice or if they occured as a result of the post at the moment it broke.


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    Well, I'll make some generalizations here, but here's a quick guess..

    Judging by the pic (I can't really tell b/c I can't see enough detail), it looks like a crack may have initiated here (arrow) and slowly propagated outward towards the line. Every loading cycle would cause the crack to propagate further. (front side of post in Tension and back side in Compression, cracks propagated through tension side due to opening and closing of crack from loading cycles)

    The surface looks smooth up until the line, indicating the area that the fatigue crack propagated through.

    To the right of the line, the remaining material wasn't strong enough to hold the stress and a shear failure (rough surface indicates this) occured, which would have deformed the rear end of the surface. The little wrinkles on the back of the post could be some straining due to the final shearing.

    Do I'll chalk it up to a fatigue failure due to some stress riser/imperfection.

    *edit* Glad you were OK
    Attached Images Attached Images

  15. #15
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    Geez that scares the crap out of me, and its a 31.6mm post too!

    I guess I will be examining my 31.6mm straight post tonight real careful. From the lack of shiny rub points in the fracture zone it looks like it happened more or less all at once, sure looks thin on the relieved side.

    Thanks for sharing with us, you may have saved someone elses rectum if they have a similar post issue. Glad you weren't hurt, it could have been real nasty.

    Kinda makes me rethink the weight savings from these seat posts, for the small amount of weight a straight gauge tube sure sounds safer.

  16. #16
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    Can't say I've seen a report of anything like the OP experienced FWIW. Everyone's gonna have a problem here and there. I think you can usually rely on Thomson's products more than many others in any case...
    "...the people get the government they deserve..."
    suum quique

  17. #17
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    OP, how much do you weigh?




    /hoping it's twice as much as I weigh

  18. #18
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    Quote Originally Posted by RookieBeotch
    Is this even common for any kind of kind of seat post, including non name brands? Just thinking about the potential injury from taking that up the rear is disturbing.
    I've broken a post, and I don't think there is a huge danger of getting sodomized by the post. When it breaks you have the seat between your a$$ and the top of the post. Now, if you forget about it as you ride on, that's a different story.

  19. #19
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    Thompson will want to see this.

    I'd send it to them for science alone. Now whether you want to see if they will cover it, that is another issue but I don't sense that you feel they are obliged

  20. #20
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    Also looks to me like a MFR issue.
    Just goes to show ALL parts need a regular check.

    Oh, I would not have expected it to fail at that point. Should have been more flex further down the shaft. I would be very sure this was a fault from production.

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    I ride nothing but Thomson, that blows my mind I thought they were indestructable. Glad to hear your ok, but 18 miles standing up...Your an ANIMAL!!!!

  22. #22
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    was anything sharp on your saddle bag rubbing the seatpost?

  23. #23
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    Caution;  Merge;  Workers Ahead! Thanks Apacherider

    Apacherider,

    I noted a similar incident on a Thomson Elite seatpost on my blog. Read it here.

    Seems like a good way to connect...

    As you will see in my writeup and the attached pictures, I did the best I could to collect all relevant details from the rider as to how he used it. Given his information (and trusting it), I don't see how the bolting ears could have just snapped off like that.

    In your case, again...I can't see how 2000 miles of riding will cause the post to crack at that spot.

    What's your weight? And did you follow all installation instructions in the manual, like torque settings on the clamps? Did the post also take a fall anytime you remember, and like someone asked before me, do you remember having put anything sharp in your saddlebag that may have marked up the post? (I do not see how that can happen when something sharp is inside your bag but for the sake of information collection, let's have it all from you...)


    Thanks...

    Ron
    Cozy Beehive Bike Blog

  24. #24
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    I noted a similar incident on a Thomson Elite seatpost on my blog. Read it here.
    This failure is not similar.

  25. #25
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    Anodized Finish ?

    Quote Originally Posted by Jerk_Chicken
    This failure is not similar.
    No, no one said its a similar failure. I said the incident is similar as in it involves a Thomson post.

    Failures with Thomson are pretty rare given their reputation among cyclists for making strong components. But these two incidents occurred not very far apart from each other (both this year). Marketing materials from Thomson claim "over 40% on ultimate strength test than the strongest production seat posts on the market" and the presence of a unique 'bending fuse' to prevent catastrophic failure. In my writeup, we determined that this fuse could be nothing more but a fancy term for the cushion of safety achieved by the elliptical bore, specifically in the lateral sections of the post where it is thinnest, as opposed to the bolt ear locations which are thickest. Due to this, the sides of the post folds before the fore and aft sections having the bolt ears do, offering some degree of protection to the cyclist from a fall.

    What could be interesting about the pictures provided by apacherider is that the ideas behind the "bend, not break" philosophy and the elliptical bore may be insignificant in reality...because as Civil pointed out here before, the crack originated on the thicker section (pointed by red arrow). But that's needs confirming through a fracture analysis.

    Just one final thought. The black finish is beautiful. It is chemically polished and then anodized. But my mind keeps asking whether this treatment makes the post any more susceptible for failure. Jobst Brandt, mechanical engineer and author of "The Bicyle Wheel", didn't favor anodized rims, advising that when rims are anodized, a thin layer of porus, Al oxide is the result and the problem is that this oxide material is extremely hard but brittle. This makes the rim more susceptible to cracking and fatigue failure. This is actually a well known issue in materials circles. As Al bends elastically, the anodized surface cracks and the crack grows into the body of the Al. Anodized aluminum only worsens the fatigue limitations of Al. You can't bend anodized Al significantly without cracking it. The cracks that develop on the coating are stress risers and potential sources for fatigue failure in the substrate metal.

    Could the same be said for this seatpost, which also has an anodized finish? My feeling is that anodizing is a bad choice for a part made to take bending.
    Last edited by Cozy.Beehive; 04-12-2009 at 01:00 AM.

  26. #26
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    No, no one said its a similar failure. I said the incident is similar as in it involves a Thomson post.

    Failures with Thomson are pretty rare given their reputation among cyclists for making strong components. But these two incidents occurred not very far apart from each other (both this year). Marketing materials from Thomson claim "over 40% on ultimate strength test than the strongest production seat posts on the market" and the presence of a unique 'bending fuse' to prevent catastrophic failure. In my writeup, we determined that this fuse could be nothing more but a fancy term for the cushion of safety achieved by the elliptical bore, specifically in the lateral sections of the post where it is thinnest, as opposed to the bolt ear locations which are thickest. Due to this, the sides of the post folds before the fore and aft sections having the bolt ears do, offering some degree of protection to the cyclist from a fall.

    What could be interesting about the pictures provided by apacherider is that the ideas behind the "bend, not break" philosophy and the elliptical bore may be insignificant in reality...because as Civil pointed out here before, the crack originated on the thicker section (pointed by red arrow). But that's needs confirming through a fracture analysis.

    Just one final thought. The black finish is beautiful. It is chemically polished and then anodized. But my mind keeps asking whether this treatment makes the post any more susceptible for failure. Jobst Brandt, mechanical engineer and author of "The Bicyle Wheel", didn't favor anodized rims, advising that when rims are anodized, a thin layer of porus, Al oxide is the result and the problem is that this oxide material is extremely hard but brittle. This makes the rim more susceptible to cracking and fatigue failure. This is actually a well known issue in materials circles. As Al bends elastically, the anodized surface cracks and the crack grows into the body of the Al. Anodized aluminum only worsens the fatigue limitations of Al. You can't bend anodized Al significantly without cracking it.

    Could the same be said for this seatpost, which also has an anodized finish? My feeling is that anodizing is a bad choice for a part made to take bending.
    Your theory doesn't take into account that the moment Al is exposed to air, its surface oxidizes anyway. It's true, it's not controlled oxidation as Anodizing is, but there is a thin layer (thinner than anodization) that is actually protective.

    You obviously haven't seen plenty of non-anodized parts bent that exhibit cracks like that.

    Additionally, you're relating two things incorrectly. The cracks are on the back, and from shifting and bending as the last piece of the post was was still attached there. Some of your words here, and on your site, are looking like Alex Jones conspiracy theories, just jumping around for conclusions. And we get it. You're looking to get people to visit your site. Big deal. The post cracked, either from impact in a crash while riding, rider, anything, then the crack worked its way backwards and tore off. We can have a multitude of theories here, in and against the OP's favor, but there's also a history of Thomson's posts as having a low rate of failure and outlasting bikes.

  27. #27
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    Quote Originally Posted by Jerk_Chicken
    Your theory doesn't take into account that the moment Al is exposed to air, its surface oxidizes anyway. It's true, it's not controlled oxidation as Anodizing is, but there is a thin layer (thinner than anodization) that is actually protective.

    You obviously haven't seen plenty of non-anodized parts bent that exhibit cracks like that.

    Additionally, you're relating two things incorrectly. The cracks are on the back, and from shifting and bending as the last piece of the post was was still attached there. Some of your words here, and on your site, are looking like Alex Jones conspiracy theories, just jumping around for conclusions. And we get it. You're looking to get people to visit your site. Big deal. The post cracked, either from impact in a crash while riding, rider, anything, then the crack worked its way backwards and tore off. We can have a multitude of theories here, in and against the OP's favor, but there's also a history of Thomson's posts as having a low rate of failure and outlasting bikes.


    For a successful surface preparation before anodizing, an AL surface is chemically cleaned off all oxides and this is a basic requirement for the process. [See : AL and AL Alloys, ASM Handbook, Joseph Davis] I'm not sure what other intermediate oxide you're talking about. Please clarify.

    Anodizing significantly decreases the fatigue strength of Al alloys. I based my judgment off that fact. I acknowledged the reputation of Thomson components already, as you can see. Infact, I'm a Thomson seatpost user and I wouldn't install one on my bike if I didn't think it was good. But again, no design is perfect. Not sure why you're so angry but you need to calm down. Again, if you actually read my blog post, you'd see that I made an effort to collect facts and discuss what might have caused the failure, since I understand a lot of folks may be using this product. You're quick to jump to narrow judgments.

    Way to inform others about your knowledge though....

  28. #28
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    For a successful surface preparation before anodizing, an AL surface is chemically cleaned off all oxides and this is a basic requirement for the process. [See : AL and AL Alloys, ASM Handbook, Joseph Davis] I'm not sure what other intermediate oxide you're talking about. Please clarify.
    Way to inform others about your knowledge though....
    I'm displaying the contrast between the two parts of your post. You either don't read very well (comparing my post, and your first paragraph), or you don't want to read well and want to keep referring to your big book 'o knowledge.

    And anger? Where do you gather that from? This is a message board and this is entertainment. You just don't seem to like when opinions counter yours because you have a book. You and Alex Jones should pair up.

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    Quote Originally Posted by Jerk_Chicken
    I'm displaying the contrast between the two parts of your post. You either don't read very well (comparing my post, and your first paragraph), or you don't want to read well and want to keep referring to your big book 'o knowledge.

    And anger? Where do you gather that from? This is a message board and this is entertainment. You just don't seem to like when opinions counter yours because you have a book. You and Alex Jones should pair up.

    Ok I will pair up if I wish. Tell me something. What oxide were you talking about? Thought you were going to reply to that. I acknowledge my mistake... I meant to say the wall thickness of the post body are thinnest at the sides, when you look from the bottom. It is more thicker to the front and rear.
    Last edited by Cozy.Beehive; 04-12-2009 at 02:39 AM.

  30. #30
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    The answer is in post 26.

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    Quote Originally Posted by Jerk_Chicken
    The answer is in post 26.
    I did see that and replied right away that before anodizing, the industry standard is to chemically clean the surface off any pre-existing oxides to ensure a good anodized finish through electrolysis, which you didn't bother replying to.

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    I did see that and replied right away that before anodizing, the industry standard is to chemically clean the surface off any pre-existing oxides to ensure a good anodized finish through electrolysis, which you didn't bother replying to.
    Then I can't help you.

    Also noted is altering your posts after I reply to them.

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    Quote Originally Posted by apacherider
    I'm OK, which is the main thing. Seriously, if I had not been riding on smooth concrete, this would have been a compete disaster. Added help was that I have a small Cannondale seatbag for a spare tube under my seat with small velcro loop that goes around the post in addition to the seat rails. That's the only thing that saved me from an aluminun colonoscopy. I have 5 Thomson seatposts and never had an issue with any of them till today. Across those posts I have over 100,000 care free miles. Owned this particular post 10 months and about 2000 miles. It's a Thomson Setback 31.6 410mm I have been using in Cannondale Caffeine framesets. The post has never been dropped, wrecked, knock over or even put in a repair stand.

    Frankly I did not think this was possible because I read that the bolts are supposed to break before the seatpost. I have not even heard of a Thomson failure before.

    Apache, no where did I come across a statement that their bolts are supposed to break before the seatpost. I would expect something like this to be counterproductive to safety. If the bolts break, the saddle comes off and there goes the rider.

    From marketing materials, this is said : "Under severe impact the Thomson seatpost would bend slightly and allows the rider to come to a safe stop or finish the ride. The ride could continue."

    Putting this alongside what you actually experienced, things do not add up.

  34. #34
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    Quote Originally Posted by Cozy.Beehive
    Apacherider,

    I noted a similar incident on a Thomson Elite seatpost on my blog. Read it here.

    Seems like a good way to connect...

    As you will see in my writeup and the attached pictures, I did the best I could to collect all relevant details from the rider as to how he used it. Given his information (and trusting it), I don't see how the bolting ears could have just snapped off like that.

    In your case, again...I can't see how 2000 miles of riding will cause the post to crack at that spot.

    What's your weight? And did you follow all installation instructions in the manual, like torque settings on the clamps? Did the post also take a fall anytime you remember, and like someone asked before me, do you remember having put anything sharp in your saddlebag that may have marked up the post? (I do not see how that can happen when something sharp is inside your bag but for the sake of information collection, let's have it all from you...)


    Thanks...

    Ron
    Cozy Beehive Bike Blog
    Read your link. Wow! You really got in depth there.

    To answer your questions, I weigh anywhere from 190-200lbs depending on the time of year. I only ride XC, mostly fire roads, XC trails and pavement. That post has never been in a wreck, collision, never hit a tree, post or pole. Never even been in a repair stand.

    Installation instructions were followed to the letter. Not so much for the seat post's sake but because I have an expensive Fizik saddle and do not want to bugger it up. Like I said in my post above, it is a 31.6mm 410, which fits the Cannondale Caffeine. I was using it in a 2009 Cannondale 29er 2, that I have only owned since early March. I have been over that bike with a fine tooth comb a dozen times since I bought it. Here is the top tube/seattube junction:



    Brand new bike for the most part. Maybe 800 miles on the frame, only 50 of which were on dirt.

    Here are a few more photos with the hardware removed. Gives one a better sense of where it broke:

    Back:

    Front:


    Also included a photo of the saddlebag I use, since you asked about it.


    Must just be a complete fluke that it broke. Like I said, I have used Thomson seatposts for a decade, 100,000 miles worth. I'm one of their biggest fans. Just left me scratching my head as to how it broke. I average about 800-1000 miles a month riding, so this was a very low mileage part for me.

    I'll get in contact with them on Monday and see about a warranty replacement. Still have the cloth bag it came in too!

  35. #35
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    This is not that big of a mystery. Things break. Even high quality things that almost never break sometimes break. It's like the lottery: You can pretty much count on NOT winning with near certainty, and it is a huge surprise when you do, but it's not "how could this possibly happen?"

    I would say that after 100,000 miles, it is not that outlandish that you could see some unlikely event, such as one of these failing. That's what, 5,000 20-miles rides? A 20 mile ride every day for almost 14 years?

    After 2,000 miles (100 20-mile rides, or roughly three 20-milers per week for the ten months you've had it) I find it unlikely that you can say for certain that there was never any damage that happened to the post, or some blow that could have started the crack. Not saying you did it, but I can't see how that could possibly be ruled out.

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    Quote Originally Posted by kapusta
    I find it unlikely that you can say for certain that there was never any damage that happened to the post, or some blow that could have started the crack. Not saying you did it, but I can't see how that could possibly be ruled out.
    Just to rule that out, I don't have so much as a scratch of any kind on my saddle. It's a Fizik with 5000 miles on it. Like I have said, no damage to the seatpost. Besides, that failure is so far up underneath the saddle nose(on the front) and basically under the rails(on the rear), that I don't think anything could contact it. It. Just. Broke.


  37. #37
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    Quote Originally Posted by kapusta
    This is not that big of a mystery. Things break.
    Very true, but the question is why. Riding mishap? Installation error? Manufacturing defect?

    Quote Originally Posted by kapusta
    I find it unlikely that you can say for certain that there was never any damage that happened to the post, or some blow that could have started the crack. Not saying you did it, but I can't see how that could possibly be ruled out.
    While it may not be certain, it's highly unlikely that something would have hit that area while riding. It's very high on the post, almost hidden by the bolt, and shielded by his legs. For an item small enough to hit that exact spot, with enough force to damage the post, while dodging all the obstacles in the way is pretty low on the probability scale. Not impossible, but unlikely.

    Probably not an installation error, that would have failed the post at the seat-tube clamp or post bolt.

    A much more probable solution was that there was some kind of stress riser there from the manufacturing process.

    Or it was damaged in shipping and handling. That being said, for it not to be noticed during installation would mean a very small damaged area which would require a very large force by a very small object. Possibly your room-mate with a hammer and nail punch. Do you have any enemies that would benefit from your passing?
    Last edited by civil; 04-12-2009 at 08:58 AM.

  38. #38
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    Quote Originally Posted by civil
    Possibly your room-mate with a hammer and nail punch.
    I was thinking pissed off ex.

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    Regardless, I still want a Thomson post for my bike.

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    Quote Originally Posted by kapusta
    I was thinking pissed off ex.
    Even more likely

    Quote Originally Posted by RookieBeotch
    Regardless, I still want a Thomson post for my bike.
    PM apacherider, I think he has one for cheap.

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    Quote Originally Posted by apacherider
    Read your link. Wow! You really got in depth there.

    To answer your questions, I weigh anywhere from 190-200lbs depending on the time of year. I only ride XC, mostly fire roads, XC trails and pavement. That post has never been in a wreck, collision, never hit a tree, post or pole. Never even been in a repair stand.

    Installation instructions were followed to the letter. Not so much for the seat post's sake but because I have an expensive Fizik saddle and do not want to bugger it up. Like I said in my post above, it is a 31.6mm 410, which fits the Cannondale Caffeine. I was using it in a 2009 Cannondale 29er 2, that I have only owned since early March. I have been over that bike with a fine tooth comb a dozen times since I bought it.

    Must just be a complete fluke that it broke. Like I said, I have used Thomson seatposts for a decade, 100,000 miles worth. I'm one of their biggest fans. Just left me scratching my head as to how it broke. I average about 800-1000 miles a month riding, so this was a very low mileage part for me.

    I'll get in contact with them on Monday and see about a warranty replacement. Still have the cloth bag it came in too!

    Sounds good. Let us know how the conversation goes. The last time I tried emailing them on this topic, their email wasn't even working. I figured concerns about the reliability of the seatpost must have flooded their inbox, but in reality...a lady who worked there told me that they were having some work done to their telephone network. Either way, if you're going to call them based on the number on their website, its going to go to a call center...the people who work there may have limited knowledge about technical issues. Just a heads up.

  42. #42
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    This has been an interesting read , I run thomson posts on two of my bikes and no problems thus far ( like 99 % of us) . As Kapusta said " it`s like winning the lottery" I think that is a pretty good point . Thomson posts , stems are some of the strongest in the industry . I think this thread is just another good reason to inspect our equipment when mantaining it . I know you won`t catch every hairline crack, but you never know what you might find .
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  43. #43
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    Quote Originally Posted by Jerk_Chicken
    Your theory doesn't take into account that the moment Al is exposed to air, its surface oxidizes anyway. It's true, it's not controlled oxidation as Anodizing is, but there is a thin layer (thinner than anodization) that is actually protective.

    You obviously haven't seen plenty of non-anodized parts bent that exhibit cracks like that.

    Additionally, you're relating two things incorrectly. The cracks are on the back, and from shifting and bending as the last piece of the post was was still attached there. Some of your words here, and on your site, are looking like Alex Jones conspiracy theories, just jumping around for conclusions. And we get it. You're looking to get people to visit your site. Big deal. The post cracked, either from impact in a crash while riding, rider, anything, then the crack worked its way backwards and tore off. We can have a multitude of theories here, in and against the OP's favor, but there's also a history of Thomson's posts as having a low rate of failure and outlasting bikes.
    The answer is in post 26..I looked, and there it is!
    I think JC is talking about a non-anodized post becoming "anodized" (IE oxidized) anyway when exposed to the elements. Thereby nullifying to some extent the claim that anodizing is worse than non anodized!
    By Jove!
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  44. #44
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    I had a seatpost break once when I first started to ride. It was not a Thomson so I am not as talented as apacherider. I was on a really fast downhill and I just jumped off a small lip and when I landed all I heard was PING and I was on the ground looking at the sky. Had a round bruise in the middle of my chest so I think there is less chance of rectal damage and more chance of torso damage. I had to ride 7 miles back standing up and I thought that was bad....18 miles!

  45. #45
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    I guess we all should get thermal cams then. Easy to spot a crack with a thermal cam!

  46. #46
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    Quote Originally Posted by CdaleTony
    The answer is in post 26..I looked, and there it is!
    I think JC is talking about a non-anodized post becoming "anodized" (IE oxidized) anyway when exposed to the elements. Thereby nullifying to some extent the claim that anodizing is worse than non anodized!
    By Jove!
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    How does it nullify it? Just cause nicks of exposed aluminum oxidized slightly doesn't mean it has the same affect that a large scale chemical anodization does. It raises a question that needs to be researched but far from nullifies the original statement.

  47. #47
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    Yeah, this has been interesting. Thomson makes some nice, tough seatposts, but as already stated, nothing is indestructible. The only Thomson seatpost issue I've ever seen is the "crimping" that can occur, usually in cases of overtighening the post collar at the seat tube. Seatposts shouldn't be overtightened, but a Thomson is one such post that can develop a "waist" at the point of normal seating height. Not that the Thomson is the only one that can have this occur. Even then, however, I've never seen one break at that "waisted" spot on the post. Usually the only evidence of this is when the post won't stay put exactly where you tighten it.

  48. #48
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    OK from an industry standpoint Thompson stuff is great and has one of the best reps around, but they're far from perfect. I've installed a few hundred posts and stems and seen a good number of broken and poorly-machined parts. Of course I don't know of a post maker I haven't seen break. Parts breakages are part of the game and it's so much better than 10-20 years ago. I generally tell folks that if you have a lightweight post, stem, or bar think about replacing them after 10,000 miles.

    Personally I have a Control Tech, a couple American Classic, and various Campy posts that are well over a decade old and 10,000 miles was a long time ago on all of them. I also have a superlight ti McMahon post that supposedly "always broke" still running strong. I know I'm on borrowed time on each of these posts and I just keep that in mind when I ride. It's not about if a part will break, it's about when it'll break.

    Again, Thompson parts are some of the most reliable parts in the industry, but they won't last forever.

  49. #49
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    Its a brittle fracture, I guess all these common aluminum alloys breaks brittle more or less. What could have caused it? I dont know, anything from bad hair day to alloying % being out of specs to microscopic pores to bad heat treatment or overheating while being machined etc etc etc probably 1000s of possible resons for this failure. Could be anything really
    Quote Originally Posted by Curmy
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  50. #50
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    Quote Originally Posted by longcat
    Its a brittle fracture, .......... Could be anything really
    Did you actually read any of the posts?

    There are a couple of educated guesses with some valid reasoning behind them which point to a specific answer.

  51. #51
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    Quote Originally Posted by civil
    Did you actually read any of the posts?
    Yes, all of them.
    Quote Originally Posted by Curmy
    Carbon is a fad.
    Quote Originally Posted by robicycle
    Just lube your ass with asscream and ride for how long you want.

  52. #52
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    Quote Originally Posted by longcat
    Yes, all of them.
    Your previous post begs to differ.

    Quote Originally Posted by longcat
    etc etc etc probably 1000s of possible resons for this failure. Could be anything really
    The damaged x-section gives plenty of info to narrow it down to a few things.

  53. #53
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    Quote Originally Posted by civil
    Your previous post begs to differ.



    The damaged x-section gives plenty of info to narrow it down to a few things.
    Does it? Could you elaborate?
    Quote Originally Posted by Curmy
    Carbon is a fad.
    Quote Originally Posted by robicycle
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  54. #54
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    Quote Originally Posted by longcat
    Does it?
    Absolutely.

    Quote Originally Posted by longcat
    Could you elaborate?
    See post #14 and #26 for some opinions and reasoning.

    Are you sure you read all the posts?

  55. #55
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    civil just because there are some people posting good speculation, and it is only speculation, there can be a thousand other reasons the part fails. No one on this thread has done any kind of xray or dye penetration tests, or even FEA. We're all a bunch of folks on the internet and if you hadn't heard 'everybody on the internet is an expert.'

  56. #56
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    Quote Originally Posted by themanmonkey
    civil just because there are some people posting good speculation, '
    There's wild speculation, and there's speculation with reason.

    I have seen 3 reasonable guesses with some evidence that make it seem plausible.

    I took note of the previous poster's comment b/c it was obvious that he didn't read the thread at all and gave some wild speculation and I called him on that. No big deal, I skim through threads all the time an miss details.

    If you read my post, which I'm sure you did, you will see that I state the limitations of my interpretation.

    Quote Originally Posted by themanmonkey
    there can be a thousand other reasons the part fails.
    Yes there can, but looking at the evidence can help point to a probable cause, and reduce the it from thousands to several.

    Quote Originally Posted by themanmonkey
    or even FEA.
    Funny this topic came up actually, here is a project I did just 2 days ago on my Thomson setback post. Is it correct? Who knows......probably not given my crap Abaqus skills . But it was fun.
    Attached Images Attached Images

  57. #57
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    Quote Originally Posted by civil

    Funny this topic came up actually, here is a project I did just 2 days ago on my Thomson setback post. Is it correct? Who knows......probably not given my crap Abaqus skills . But it was fun.
    Nice paint job

  58. #58
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    Thanks, I was worried it was going to be too blingy

  59. #59
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    If you need any proof that Thomson is a great company, check this out. I sent them an email late this afternoon, outlining my seatpost issue. Thought nothing of it, considering it's Easter Sunday afternoon. Probably hear back later in the week. Boy was I shocked when someone sent me an email almost right back regarding replacement of the post! On Easter Sunday!

    Can you believe that?

    Great companies do business this way.

  60. #60
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    Quote Originally Posted by civil
    Funny this topic came up actually, here is a project I did just 2 days ago on my Thomson setback post. Is it correct? Who knows......probably not given my crap Abaqus skills . But it was fun.
    But doesn't include the radius where the fatigue occurred....

    Your analysis of the fracture (post #14) is correct...only thing I would add is that I see multiple fatigue origins on the tensile side of the post (there are "ratchet" marks along about a 5 mm length) rather than just one initiation site. This argues against the discreet material defect theory and for the theory of "just plain exceeded the fatigue strength of the material".

  61. #61
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    Quote Originally Posted by CdaleTony
    The answer is in post 26..I looked, and there it is!
    I think JC is talking about a non-anodized post becoming "anodized" (IE oxidized) anyway when exposed to the elements. Thereby nullifying to some extent the claim that anodizing is worse than non anodized!
    By Jove!
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    Sir, unless you come to this thread armed with Tobin's Spirit Guide, you are not welcome here

  62. #62
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    Quote Originally Posted by apacherider
    Can you believe that?
    Yep, that's the reason they're one of the most respected names making bike parts. It's also is the reason the post is one of the best reviewed parts over in the reviews section.

  63. #63
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    Quote Originally Posted by steadite
    But doesn't include the radius where the fatigue occurred....
    Yeah, I should have clarified, that was just for an unrelated project I was doing on my own. I only posted it b/c thought it was funny how I had just recently finished that and this thread came up. They are only related by the product name....

    Quote Originally Posted by steadite
    ........only thing I would add is that I see multiple fatigue origins..........This argues against the discreet material defect theory and for the theory of "just plain exceeded the fatigue strength of the material".
    I can't see the ratchet marks very well, my eyes are not as good as they used to be so I'll take your word for it (a high quality pic of that area would help me). However, if it was the case of just exceeding the fatigue strength of the material, does it surprise you that it occurred at such a low cycle count (used for ~ 2000 miles)?

  64. #64
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    I visited the Thomson factory in Georgia once on a road trip. In fact, the late Mr. Thomson himself was there, on a Sunday! I came to ride their trail network that they had behind the factory just to break up the monotony of a road trip, but ended up touring the factory and checking out some new parts they had and chatting with them for a bit. They are a super cool company and very nice guys. When I saw this thread I was sure they would take care of you regardless of what the problem was. They charge a premium but the service and quality you get justify it! That said, nothing is 100% and even good parts break or have defects once in a while.

  65. #65
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    Quote Originally Posted by civil
    if it was the case of just exceeding the fatigue strength of the material, does it surprise you that it occurred at such a low cycle count (used for ~ 2000 miles)?
    Well, the whole thing flies in the face of everyone else's experience: the fact that these posts don't generally break. With trail bumps and whatnot, I suppose it's reasonable that a lot of cycles could be racked up in 2000 miles (100 bumps per mile would be 200k cycles).

    Who knows...maybe the material wasn't aged right (low hardness)...maybe some machining damage (surface deformation or tool marks) or anodizing pits that we can't see...they need a real failure analysis...one with microscopes involved!!

    I do agree with the statement that anodizing is bad for aluminum fatigue---that's a known thing. it's done successfully on bike components all the time tho. The natural oxidation that occurs in air is not nearly as thick as the anodized layer.

    To the OP...don't rub the fractures together and wrap them in paper towel separately in ziplock bags b4 sending back. hard for their lab to analyze the fracture if they're all rubbed up.
    Last edited by steadite; 04-13-2009 at 07:49 AM.

  66. #66
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    Those are the first 2 I have ever heard or seen break.

  67. #67
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    Yes, I did read every reply but I didn't see anything mentioned about: were all the OPs other Thomson seatposts "setback" posts and...could the potential for failure in a Thomson seatpost be possibly higher because it is a setback? I have four Thomson straight seatposts working now with two more in a box.
    So it seems to me to be, this thing that I think I see.

  68. #68
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    Quote Originally Posted by xcguy
    Yes, I did read every reply but I didn't see anything mentioned about: were all the OPs other Thomson seatposts "setback" posts and...could the potential for failure in a Thomson seatpost be possibly higher because it is a setback? I have four Thomson straight seatposts working now with two more in a box.
    All my other posts are traditional straight seatposts. Don't think that really matters though since the failure occured up near the top. If you try to visualize it, I don't see how the bend further down the seatpost could be a cause.

  69. #69
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    Just figured I would throw in my two pennies here...I have four bikes with Thomson posts and stems. The oldest one is on a full sus. cross bike that is nearly ten years old. In 2004 the face plate developed a crack. I called up Thomson and they sent me a new one, no questions asked. About three weeks ago, my brother was riding the above mentioned bike and as he got to the top of a steep loose gravel climb, he said "I think something is wrong with the handlebars" Upon further inspection the bars had rotated. I straightened the bars and went to tighten the steerer tube clamp bolts and noticed they were very loose. The bike does not get much use these days and spent most of the winter in my unheated garage. I did not think much of and we finished the ride (probably another hour or so). Well the following weekend I grabbed the bike to go for a ride and noticed a crack from top to bottom on the back of the steerer tube clamp. It is a black stem and there is no way I would have missed that on the trail...perhaps I over tightend the bolts, perhaps there already was a hairline crack...who know...I called up Thomson and they said to send it back and they would send me a new one. The stem got here about a week later, no questions asked. THEY REPLACED A PART NEARLY 10 YEARS OLD!! THOMSON ROCKS!

    Ok, well I have rambled enough...glad to hear you are ok and that they took care of you too.

    Cheers,

    Doug

  70. #70
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    Quote Originally Posted by steadite

    To the OP...don't rub the fractures together and wrap them in paper towel separately in ziplock bags b4 sending back. hard for their lab to analyze the fracture if they're all rubbed up.

    I already mailed it before I read your post.The head of the post I wrapped in a paper towel, then stuck it in the Thomson bag with the rest of the post, inside a bubble mailer.

  71. #71
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    Quote Originally Posted by apacherider
    All my other posts are traditional straight seatposts. Don't think that really matters though since the failure occured up near the top. If you try to visualize it, I don't see how the bend further down the seatpost could be a cause.
    Trust me, I'm no engineer but every time I look at a "setback" or "layback" seatpost it seems to me that there would be stresses applied totally unlike with a straight post along its entire length.
    So it seems to me to be, this thing that I think I see.

  72. #72
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    Quote Originally Posted by apacherider
    That post has never been in a wreck, collision, never hit a tree, post or pole. Never even been in a repair stand
    You ride 2000 miles without crashing once? That's insane.
    beaver hunt

  73. #73
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    Quote Originally Posted by snowdrifter
    You ride 2000 miles without crashing once? That's insane.
    Nope. No wrecks. No falling down. Nearly all my riding with that seatpost was on pavement. Some fireroads, some singletrack. I spend more than half my time in Dallas, the balance in Taos, NM. The Cannondales that I ride with this particular seatpost have spent over 90% of it's time in Dallas rather than Taos.

    Plus, much of last year (spring and summer) I was recovering from a monster huge car accident I was in, that occured in October 2007. Car drivers fault, ruined a road bike, I got a nice check. Broken ribs, messed up tailbone, shoulder etc. So....all last spring and summer I would ride everyday, but just on pavement. Falling and wreckin' was verboten! Pretty incredible how careful you can be while riding if you are scared of re-breaking a rib.

  74. #74
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    since it was in a cannondale, it looks like it heard that cannondale's will now be made in taiwan and it's head exploded.

  75. #75
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    Thomson setback posts are machined and then bent to the setback position. You would think if there were any fatigue points they would be caused by this. This doesn't appear to be the case in apacherider's situation though.
    Riding Fat and still just as fast as I never was.

  76. #76
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    Quote Originally Posted by crashtestdummy
    Thomson setback posts are machined and then bent to the setback position. You would think if there were any fatigue points they would be caused by this. This doesn't appear to be the case in apacherider's situation though.
    I'm not talking about "induced" fatigue points caused by the actual bending/manufacturing process. I'm talking about the funky forces caused by the saddle not being in the same relative position as on a straight post (maybe even exacerbated by the saddle being back on the rails).

    Again, I'm no engineer but it seems clear to me that it just isn't the same situation all around, setback vs straight. Doesn't it seem odd that the OP has a history of Thomson seatposts and the only one he's broken was a setback?

    We all know Thomson makes the best seatposts but I wonder if their parameters for a setback are as stringent as on their straight ones? You know, like they might be saying "setbacks aren't the best way to re-position a rider (due to long thighs or too-short a top tube or whatever) but if the rider really wants one we'll give him one, even though it's not going to be as strong as our straight seatposts". Maybe. Kind of like doing curls with your elbows out in front of you and not at your sides.
    So it seems to me to be, this thing that I think I see.

  77. #77
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    Setback seatposts used to be used much, much more than inline posts, so I don't really think so.

  78. #78
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    Quote Originally Posted by xcguy
    I'm not talking about "induced" fatigue points caused by the actual bending/manufacturing process. I'm talking about the funky forces caused by the saddle not being in the same relative position as on a straight post (maybe even exacerbated by the saddle being back on the rails).

    Again, I'm no engineer but it seems clear to me that it just isn't the same situation all around, setback vs straight. Doesn't it seem odd that the OP has a history of Thomson seatposts and the only one he's broken was a setback?

    We all know Thomson makes the best seatposts but I wonder if their parameters for a setback are as stringent as on their straight ones? You know, like they might be saying "setbacks aren't the best way to re-position a rider (due to long thighs or too-short a top tube or whatever) but if the rider really wants one we'll give him one, even though it's not going to be as strong as our straight seatposts". Maybe. Kind of like doing curls with your elbows out in front of you and not at your sides.
    The seat on that particular seatpost was pretty far back on the rails. Meaning in addition to having the setback post, I had the seat moved back a little further back beyond the neutral position on the rails. If that makes sense. The result was that the post was clamped on the forward 1/3 of the usable rail area. Not sure if that made a difference or not but it would have given a little bit more leverage on the top end of the post. Although I bet my saddle rails would have bent before the seatpost did.

  79. #79
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    Quote Originally Posted by steadite
    But doesn't include the radius where the fatigue occurred....

    Your analysis of the fracture (post #14) is correct...only thing I would add is that I see multiple fatigue origins on the tensile side of the post (there are "ratchet" marks along about a 5 mm length) rather than just one initiation site. This argues against the discreet material defect theory and for the theory of "just plain exceeded the fatigue strength of the material".
    This is correct - there is a large process zone there where the material fatigued. Only thing wrong in that post is the assertion that there was subritical crack growth through 1/2 of the circumference - you can see the crack origin pretty clearly and the crack would have gone to a critical flaw size well before that. T6 aluminum is a 40ksi material and pretty much linear to very close to failure. The rider must have been putting some serious weight down on the nose of his saddle (many times).

    I'm surprised to see such a process zone in T6.

  80. #80
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    Quote Originally Posted by apacherider
    Nope. No wrecks. No falling down. Nearly all my riding with that seatpost was on pavement. Some fireroads, some singletrack. I spend more than half my time in Dallas, the balance in Taos, NM. The Cannondales that I ride with this particular seatpost have spent over 90% of it's time in Dallas rather than Taos.

    Plus, much of last year (spring and summer) I was recovering from a monster huge car accident I was in, that occured in October 2007. Car drivers fault, ruined a road bike, I got a nice check. Broken ribs, messed up tailbone, shoulder etc. So....all last spring and summer I would ride everyday, but just on pavement. Falling and wreckin' was verboten! Pretty incredible how careful you can be while riding if you are scared of re-breaking a rib.
    Apache,

    This is interesting because if this is true, you're essentially telling us that you didn't abuse it. However, what I was interested in knowing was whether you used a torque wrench to tighten the bolts. According to Thomson, a majority of failures like these happen due to over torquing. You're really lucky to escape without injury. Let us know your thoughts on this.



    -Ron

  81. #81
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    Quote Originally Posted by Cozy.Beehive
    Apache,

    This is interesting because if this is true, you're essentially telling us that you didn't abuse it. However, what I was interested in knowing was whether you used a torque wrench to tighten the bolts. According to Thomson, a majority of failures like these happen due to over torquing. You're really lucky to escape without injury. Let us know your thoughts on this.



    -Ron
    Yes. I used a torque wrench. I use a torque wrench on virtually all my bike parts. In the past, back when I used square taper bottom brackets, using a torque wrench was essential. I have kept that practice up over the years. I'm 100% positive a torque wrench was used on this particular seatpost. Matter of fact, if you look at one of the bolts, you can see where I kind of buggered up the head of one of them with the torque wrench as it slipped off.

    Besides, where the seatpost broke is far removed from the area where the bolts affix to the seatpost itself. I do not see how there could be any correlation.

    Like I have said before, I'm a big fan of Thomson seatposts. I have them on many of my bikes. I would never consider using anything but them. I have gone through and carefully looked at all my other Thomsons, checked for cracks and also checked the torque on the bolts. Each were crack free and right on the money.

  82. #82
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    I wouldn't worry about it Apache. Manufacturers buy metal in bulk, and then process it into a final product. Sometimes the metal has defects. Thompson is pretty good at detecting flawed material, and their machining techniques are top-notch. I'm no expert metalurgist, but I've got a little experience from the machinists end. Looks like there was a flaw that slowly expanded to failure. It happens. See if Thompson is willing to warranty the post, and call it a day.

  83. #83
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    Quote Originally Posted by Barkleyfan
    I wouldn't worry about it Apache. Manufacturers buy metal in bulk, and then process it into a final product. Sometimes the metal has defects. Thompson is pretty good at detecting flawed material, and their machining techniques are top-notch. I'm no expert metalurgist, but I've got a little experience from the machinists end. Looks like there was a flaw that slowly expanded to failure. It happens. See if Thompson is willing to warranty the post, and call it a day.

    You seem to be inventing your own little story here. I have been in talks with Thomson and so far, no mention was made of defective material. They absolutely stand by their products. It seems you know more about their material than they do.

  84. #84
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    Quote Originally Posted by Cozy.Beehive
    You seem to be inventing your own little story here. I have been in talks with Thomson and so far, no mention was made of defective material. They absolutely stand by their products. It seems you know more about their material than they do.
    I think you meant to say you work for Thomson. Why on earth would any manufacturer mention to a customer that there was a flaw in their product materials? You do not need to admit fault to stand by your product. You just send out a replacement item or fix it if possible.

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    Quote Originally Posted by wormvine
    I think you meant to say you work for Thomson. Why on earth would any manufacturer mention to a customer that there was a flaw in their product materials? You do not need to admit fault to stand by your product. You just send out a replacement item or fix it if possible.
    You bring together some of your "little" machinist experience working for some company in the past to make generalizations about Thomson and their QC. How come you know that their material is defective for certain? Can you spell F-L-U-F-F?

  86. #86
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    Quote Originally Posted by Cozy.Beehive
    You seem to be inventing your own little story here. I have been in talks with Thomson and so far, no mention was made of defective material. They absolutely stand by their products. It seems you know more about their material than they do.
    LMFAO Vested interest? Seriously, WTF do you care about Apaches resolution? If you wanna pretend Thompson does UT testing on every inch of every peice they put out, pretend away. Having done production level QA, I know it's highly unlikely. Especially for the price. Sometimes flaws get through.It's not the end of the world.

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    Sorry, you lose. Your attitude is the traditional way of thinking and it doesn't help. All to often its easy to say 'things break, let's move on'. If this was someone in your family getting hurt, you would probably change your outlook. Your claims about Thomson's QC is some conjecture at best. I'm also not sure what caused you to "LMFAO". All this is a circus act to you.

  88. #88
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    Cozy.Beehive has at last exposed the truth, 2 Thomson seatposts, of the thousands upon thousands of posts sold, have broke. The sky is officially falling. Thomson is not perfect, the Apocalypse has begun.

    PS anyone wanna trade their Sette for my 30.9x367 Thomson? I no longer feel safe.

  89. #89
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    Quote Originally Posted by Cozy.Beehive
    Sorry, you lose. Your attitude is the traditional way of thinking and it doesn't help. All to often its easy to say 'things break, let's move on'. If this was someone in your family getting hurt, you would probably change your outlook. Your claims about Thomson's QC is some conjecture at best. I'm also not sure what caused you to "LMFAO". All this is a circus act to you.
    If we are allowed a 0% failure rate then every manufacturer in the world would shut their doors. No product is perfect, and no amount of testing is going to ensure that it is. The idea is to design it right, build it right, and have enough QC checks in place to try and get as close to that 100% perfect as you possibly can.

    You want a product with a 0% chance for failure? Go pick up rocks and sell them as paper weights. Of course, then someone will drop one on a family member's toe and sue you anyway.

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    To the op, glad you are okay. I consider Thomson posts and stems to be the best in the industry, and it sounds like you would agree. I would let them have it for testing, but request it back, because you will need proof that you broke one.

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    Quote Originally Posted by adam728
    If we are allowed a 0% failure rate then every manufacturer in the world would shut their doors. No product is perfect, and no amount of testing is going to ensure that it is. The idea is to design it right, build it right, and have enough QC checks in place to try and get as close to that 100% perfect as you possibly can.

    You want a product with a 0% chance for failure? Go pick up rocks and sell them as paper weights. Of course, then someone will drop one on a family member's toe and sue you anyway.

    I didn't propose anywhere that the manufacturer in question has 0% failure rate.

  92. #92
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    Quote Originally Posted by Cozy.Beehive
    I didn't propose anywhere that the manufacturer in question has 0% failure rate.
    No, but you're pushing an issue, that not only isn't yours, but one that is one of the least to be concerned with in the whole of the mountain bike component world...you have more of the flavor of a lawyer looking for that very small exception on which to base a rule...
    "...the people get the government they deserve..."
    suum quique

  93. #93
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    Quote Originally Posted by MarcusSommers
    To the op, glad you are okay. I consider Thomson posts and stems to be the best in the industry, and it sounds like you would agree. I would let them have it for testing, but request it back, because you will need proof that you broke one.
    It hit their mailbox in Georgia, last friday. Should be getting a new one back any day now. No problems! Only reason I started the thread was due to the rarity of a failure. Had it been some other random part I would not even have mentioned it, much less started a thread. I hope you guys now include periodic checks of all your parts for cracks. I personally don't know when this crack formed or how long I'd been riding with it this way. Think I mentioned before, that I'm rather anal about bike maintenance, so this crack was a complete shock to me.

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    Please read on the engineering issues and analysis of the broken seatpost in question. Here's the results of my latest interview with a Thomson insider. http://cozybeehive.blogspot.com/2009...ightening.html


    Apache, you're copied to this as well. Thomson says there is no doubt in their minds that you overtightened this seat post, as much as 2.5 to 3 times the recommended values (read link above). Again, that's not me saying it. I also have a vested interest in this matter only so far as to get objective information.

  95. #95
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    What a fukin joke?

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    That was quick. Turns out you didn't even read the link I posted.

  97. #97
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    Quote Originally Posted by Cozy.Beehive
    Please read on the engineering issues and analysis of the broken seatpost in question. Here's the results of my latest interview with a Thomson insider. http://cozybeehive.blogspot.com/2009...ightening.html


    Apache, you're copied to this as well. Thomson says there is no doubt in their minds that you overtightened this seat post, as much as 2.5 to 3 times the recommended values (read link above). Again, that's not me saying it. I also have a vested interest in this matter only so far as to get objective information.
    Did you even ask anyone's permission to do such a thing?

  98. #98
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    Quote Originally Posted by Cozy.Beehive
    Please read on the engineering issues and analysis of the broken seatpost in question. Here's the results of my latest interview with a Thomson insider. http://cozybeehive.blogspot.com/2009...ightening.html


    Apache, you're copied to this as well. Thomson says there is no doubt in their minds that you overtightened this seat post, as much as 2.5 to 3 times the recommended values (read link above). Again, that's not me saying it. I also have a vested interest in this matter only so far as to get objective information.
    What else was said? We only have limited quotes and nothing you have put up there is "proof" of the claims being made. Having looked at the pics I have a hard time believing that line blaming the customer. A REALLY hard time thinking anyone with any training would see that failure and fall for that line. Your own "information" even points to holes in the lines you were fed blaming the customer.

    "Dave : "I also observed that the bolt heads are distorted. The bolts are grade 12.8. We know how much torque it requires to distort the bolt heads, and it is in excess of 125 inch pounds. ....."

    THAT is ABSOLUTELY idiotic. You are a fool for putting such a stupid comment online and thinking it supports your "case".

    In my opinion, I wouldn't "trust" any "engineer" who acted like you have been.
    No supporting evidence of your claims, reproducing claims made by others (who may or may not be qualified and ARE not independent) and misrepresenting this as being an open minded and valid investigation of an issue.


    Do you have permission to use the photos?

  99. #99
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    Smile

    Quote Originally Posted by ash240
    What else was said? We only have limited quotes and nothing you have put up there is "proof" of the claims being made. Having looked at the pics I have a hard time believing that line blaming the customer. A REALLY hard time thinking anyone with any training would see that failure and fall for that line. Your own "information" even points to holes in the lines you were fed blaming the customer.

    "Dave : "I also observed that the bolt heads are distorted. The bolts are grade 12.8. We know how much torque it requires to distort the bolt heads, and it is in excess of 125 inch pounds. ....."

    THAT is ABSOLUTELY idiotic. You are a fool for putting such a stupid comment online and thinking it supports your "case".

    In my opinion, I wouldn't "trust" any "engineer" who acted like you have been.
    No supporting evidence of your claims, reproducing claims made by others (who may or may not be qualified and ARE not independent) and misrepresenting this as being an open minded and valid investigation of an issue.


    Do you have permission to use the photos?


    Sorry that you didn't like the outcome of this case. I'm not supporting either one, just informing people of what the user did, and what Thomson says. Be known, that if you live in Georgia, and contact Dave Parett, he'll be more than happy to lead to on a factory tour to show you how everything is done. Maybe you can argue with him there? In the end, I obviously see contradications. Apache says he used a torque wrench, like he always did...Thomson claims he didn't and that their observation of the broken specimen shows there's only limited number of ways that seatpost could break. My job is to inform people that eitherway, you cannot afford to overlook the tightening values of nuts on bolts on your bike. That's some sound advice that many people in the bike industry has been giving over the years. Not many riders keep a tool like a torque wrench at home nor know how to use it. Meanwhile, you're most welcome to do a rebuttal of Dave's comments on my blog. I value the discussion. If you think something was stated wrong, come and talk about it.

  100. #100
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    Weird thing is, I use a Park Tool Torque Wrench and it only goes to 60 pounds. Huh.

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