Page 2 of 3 FirstFirst 123 LastLast
Results 51 to 100 of 142
  1. #51
    ♥ ς╥33£
    Reputation: longcat's Avatar
    Join Date
    Apr 2008
    Posts
    488
    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.

  2. #52
    mtbr member
    Reputation:
    Join Date
    Feb 2008
    Posts
    1,058
    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.

  3. #53
    ♥ ς╥33£
    Reputation: longcat's Avatar
    Join Date
    Apr 2008
    Posts
    488
    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
    Just lube your ass with asscream and ride for how long you want.

  4. #54
    mtbr member
    Reputation:
    Join Date
    Feb 2008
    Posts
    1,058
    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?

  5. #55
    Bike Dork
    Reputation: themanmonkey's Avatar
    Join Date
    Nov 2005
    Posts
    1,365
    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.'

  6. #56
    mtbr member
    Reputation:
    Join Date
    Feb 2008
    Posts
    1,058
    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

  7. #57
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,407
    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

  8. #58
    mtbr member
    Reputation:
    Join Date
    Feb 2008
    Posts
    1,058
    Thanks, I was worried it was going to be too blingy

  9. #59
    mtbr member
    Reputation:
    Join Date
    Mar 2004
    Posts
    826
    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.

  10. #60
    mtbr member
    Reputation:
    Join Date
    Jan 2007
    Posts
    1,366
    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".

  11. #61
    banned
    Reputation: Jerk_Chicken's Avatar
    Join Date
    Oct 2005
    Posts
    16,466
    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!
    CDT
    Sir, unless you come to this thread armed with Tobin's Spirit Guide, you are not welcome here

  12. #62
    Bike Dork
    Reputation: themanmonkey's Avatar
    Join Date
    Nov 2005
    Posts
    1,365
    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.

  13. #63
    mtbr member
    Reputation:
    Join Date
    Feb 2008
    Posts
    1,058
    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)?

  14. #64
    Its got what plants crave
    Reputation: Jim311's Avatar
    Join Date
    Feb 2006
    Posts
    5,934
    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.

  15. #65
    mtbr member
    Reputation:
    Join Date
    Jan 2007
    Posts
    1,366
    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.

  16. #66
    mtbr member
    Reputation: kntr's Avatar
    Join Date
    Jan 2004
    Posts
    3,611
    Those are the first 2 I have ever heard or seen break.

  17. #67
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    7,951
    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.

  18. #68
    mtbr member
    Reputation:
    Join Date
    Mar 2004
    Posts
    826
    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.

  19. #69
    mtbr member
    Reputation:
    Join Date
    Feb 2007
    Posts
    40
    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

  20. #70
    mtbr member
    Reputation:
    Join Date
    Mar 2004
    Posts
    826
    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.

  21. #71
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    7,951
    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.

  22. #72
    the train keeps rollin
    Reputation: snowdrifter's Avatar
    Join Date
    Aug 2006
    Posts
    3,212
    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

  23. #73
    mtbr member
    Reputation:
    Join Date
    Mar 2004
    Posts
    826
    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.

  24. #74
    banned
    Reputation: cruso414's Avatar
    Join Date
    Aug 2004
    Posts
    2,101
    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.

  25. #75
    NMBP
    Reputation: crashtestdummy's Avatar
    Join Date
    Jun 2005
    Posts
    2,183
    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.

  26. #76
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    7,951
    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.

  27. #77
    Unfit Norwegian
    Reputation: Dazed's Avatar
    Join Date
    Feb 2004
    Posts
    1,260
    Setback seatposts used to be used much, much more than inline posts, so I don't really think so.

  28. #78
    mtbr member
    Reputation:
    Join Date
    Mar 2004
    Posts
    826
    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.

  29. #79
    mtbr member
    Reputation:
    Join Date
    Nov 2008
    Posts
    18
    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.

  30. #80
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    31
    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

  31. #81
    mtbr member
    Reputation:
    Join Date
    Mar 2004
    Posts
    826
    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.

  32. #82
    plasma donor
    Reputation: Barkleyfan's Avatar
    Join Date
    Jul 2008
    Posts
    754
    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.

  33. #83
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    31
    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.

  34. #84
    mtbr member
    Reputation: wormvine's Avatar
    Join Date
    Oct 2005
    Posts
    3,160
    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.

  35. #85
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    31
    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?

  36. #86
    plasma donor
    Reputation: Barkleyfan's Avatar
    Join Date
    Jul 2008
    Posts
    754
    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.

  37. #87
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    31
    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.

  38. #88
    mtbr member
    Reputation:
    Join Date
    Jun 2008
    Posts
    359
    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.

  39. #89
    Braaaapp!
    Reputation: adam728's Avatar
    Join Date
    Jan 2006
    Posts
    471
    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.

  40. #90
    mtbr member
    Reputation:
    Join Date
    Sep 2008
    Posts
    668
    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.

  41. #91
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    31
    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.

  42. #92
    Old man on a bike
    Reputation: Bikinfoolferlife's Avatar
    Join Date
    Feb 2004
    Posts
    12,386
    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

  43. #93
    mtbr member
    Reputation:
    Join Date
    Mar 2004
    Posts
    826
    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.

  44. #94
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    31
    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.

  45. #95
    mtbr member
    Reputation: wormvine's Avatar
    Join Date
    Oct 2005
    Posts
    3,160
    What a fukin joke?

  46. #96
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    31
    That was quick. Turns out you didn't even read the link I posted.

  47. #97
    banned
    Reputation: Jerk_Chicken's Avatar
    Join Date
    Oct 2005
    Posts
    16,466
    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?

  48. #98
    mtbr member
    Reputation:
    Join Date
    Jun 2007
    Posts
    247
    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?

  49. #99
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    31

    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.

  50. #100
    mtbr member
    Reputation:
    Join Date
    Mar 2004
    Posts
    826
    Weird thing is, I use a Park Tool Torque Wrench and it only goes to 60 pounds. Huh.

Page 2 of 3 FirstFirst 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •