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  1. #1
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    Cracked my Syntace Racelite carbon bars today...

    I went to install my new Deda Zero stem, The stem say max torque of 8NM. That seemed a bit high in my mind. SO went with 5NM same as the Ritchey stem uses thatw as just on there.

    So Install it and wehn I tightend the bottom right bolt I heard a cracking sound. I looseded eveyhting up and there is a hairlie crack in the mesh reinforcement area the length of the stem clamp.

    I have installed a WHOLE bunch of CF bars and nothign ever like this has happened. Just what I need with a long wekend coming up and a century in 3 weeks, downtime. Well to the back-up bike....

    I ordered a new bar tonight and will deal with this on Tuesday with Syntace USA and or Performace Bike. I bought the bar new from Performance in March. I have never crashed these bars either. Maybe just a bad bar or something.....
    Last edited by DIRT BOY; 10-09-2007 at 05:57 AM.
    DIRT BOY

    "Pain is a big fat creature riding on your back. The farther you pedal, the heavier he feels. The harder you push, the tighter he squeezes your chest. The steeper the climb, the deeper he digs his jagged, sharp claws into your muscles." - Scott Martin


  2. #2
    Fat'r + Slow'r than TMB
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    Ouch....sorry to here about that. I won't even bother to ask the usual question because I know you have installed these sort of things before. Hopefully a quick replacement and fix and back on the primary bike for you. Any pics available so we can see what the heck happened or is it too small to really show? Carbon is always such a pain to photo well.

  3. #3
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    Wink

    That really stinks. I've never used Suntace bars althoguh I do know a few that do and have without any issues. I'm a Zipp SL user.

    Hopefully it works out. With Performance it should.
    For my next trick I will now set myself on fire!

  4. #4
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    Keep me posted, since I've got his bar, too.



    I'm curious, Deda uses 31.7mm, but the Syntace bar is 31.8mm. Doesn't sound like a lot of difference, but I wonder if you compressed the carbon bar too much when torquing the stem bolts down on an ever-so-slightly fatter bar?
    Ride Hard,
    Mike B.

  5. #5
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    Quote Originally Posted by 1speed_Mike
    Keep me posted, since I've got his bar, too.



    I'm curious, Deda uses 31.7mm, but the Syntace bar is 31.8mm. Doesn't sound like a lot of difference, but I wonder if you compressed the carbon bar too much when torquing the stem bolts down on an ever-so-slightly fatter bar?
    It SHOULD not matter. 31.7 is the Italian way, 31.8 is US. It's the same. I will confirm with Syntace.
    DIRT BOY

    "Pain is a big fat creature riding on your back. The farther you pedal, the heavier he feels. The harder you push, the tighter he squeezes your chest. The steeper the climb, the deeper he digs his jagged, sharp claws into your muscles." - Scott Martin


  6. #6
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    why are you running the deda zero stem? It's not even the lightest. I thought you were on the extralite stem.

  7. #7
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    Quote Originally Posted by Cheers!
    why are you running the deda zero stem? It's not even the lightest. I thought you were on the extralite stem.
    Bolts got stripped even though torque was lower than reccomended. I had too saw off them off.

    The stem is bac to Extralite foe evaluation. I wanted to try something different than the Ritchey 4-axis as the face plate finish SICKS donkey balls!
    I think the bolts are too soft and EL says I have a crappy TW.

    Now it looks like USPS lost it. I am having a bad week...

    The Deda SC in 120mm came in at 118g. Looks really nice on my bike.
    DIRT BOY

    "Pain is a big fat creature riding on your back. The farther you pedal, the heavier he feels. The harder you push, the tighter he squeezes your chest. The steeper the climb, the deeper he digs his jagged, sharp claws into your muscles." - Scott Martin


  8. #8
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    Here is a picture of the crank.

    It's bar is picture upside down.



    I just spoke with Syntace/Magura about this issue. They said they were having issues with some Racelite carbon bars cracking here the bar drops, not in the stem clamp area where I have mine. The bar is being re-designed by Jo Klieber to fix this. I am not aware of ant recall and they did not say. But id there is any possible need for one, Syntace will do it fast and easy. They had a minor issue with their F99 stems last year and did a voluntary recall and gave you a little something back for you effort (bar/stem combo for $35 off or a Torque wrench and bits for $95).

    If you have this bat, keep and I on it when changing tape. If you are that worried about it, contact Syntace and I am SURE they will take care of you. New bars arrive in 3-4 weeks.

    I have one coming today and will ride it until the new ones arrive. I have not seen or heard of any cracking issues until mine and when I try to order another pair a few weeks back and what told there was a updated model coming "due to some possible QC issues."

    If my position was not so dialed in with the fit/reach of this bar, I might have just ordered an aluminum bar till the news ones arrive.

    But Syntace told me to ride the new bar and return it to them when I get my new one on exchange and I should be fine as it's a very minor issues and it's not widespread at all.
    Last edited by DIRT BOY; 10-09-2007 at 06:16 AM.
    DIRT BOY

    "Pain is a big fat creature riding on your back. The farther you pedal, the heavier he feels. The harder you push, the tighter he squeezes your chest. The steeper the climb, the deeper he digs his jagged, sharp claws into your muscles." - Scott Martin


  9. #9
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    cause...

    A crack like that appears to be the result of a mismatch between the bar and stem diameters, assuming there is no obvious raised edge or burr on the stem. If the bar is too big or the stem clamp too small, you get line contact at the leading edge of the stem and the result is a crack from excessive pressure.

    To be safe, when installing a new bar, push it into the stem by hand to see if it catches on the leading edges of the stem. If so, then some shallow angle chamfering of the leading edges may be necessary to eliminate the interference.

    Miscalibrated click-type torque wrenches can also be a cause of such a problem. Cheap beam types wrenches are harder to read, but never need calibration. Personally, I've never used either on small M5 or M6 bolts. I use a 4-5-6 Y-style wrench and go by feel.

  10. #10
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    hoop strength

    maybe this is a good time to read Thomson's discussion on carbon for stems/posts in relation to hoop strength (which your pic illustrates):

    http://www.lhthomson.com/carbon_seatpost.htm

  11. #11
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    Quote Originally Posted by C-40
    A crack like that appears to be the result of a mismatch between the bar and stem diameters, assuming there is no obvious raised edge or burr on the stem. If the bar is too big or the stem clamp too small, you get line contact at the leading edge of the stem and the result is a crack from excessive pressure.

    To be safe, when installing a new bar, push it into the stem by hand to see if it catches on the leading edges of the stem. If so, then some shallow angle chamfering of the leading edges may be necessary to eliminate the interference.
    Thanks. I was worrired as the stem is 31.7 and the bar is 31.8. Syntace has had no known issues with this combo. They also did not reccomend using the 8nm max settign Deda says.

    I will check the new bar with the stem today like you said. If there is any issue I will stick withe the Ritchey 4-Axis whcih had none.
    DIRT BOY

    "Pain is a big fat creature riding on your back. The farther you pedal, the heavier he feels. The harder you push, the tighter he squeezes your chest. The steeper the climb, the deeper he digs his jagged, sharp claws into your muscles." - Scott Martin


  12. #12
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    Quote Originally Posted by stevesbike
    maybe this is a good time to read Thomson's discussion on carbon for stems/posts in relation to hoop strength (which your pic illustrates):

    http://www.lhthomson.com/carbon_seatpost.htm
    First time this has happended using any CF bars for 5 yrs now. MTB and Road.

    But yes, it has me wondering a bit.
    DIRT BOY

    "Pain is a big fat creature riding on your back. The farther you pedal, the heavier he feels. The harder you push, the tighter he squeezes your chest. The steeper the climb, the deeper he digs his jagged, sharp claws into your muscles." - Scott Martin


  13. #13
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    Quote Originally Posted by C-40
    Miscalibrated click-type torque wrenches can also be a cause of such a problem. Cheap beam types wrenches are harder to read, but never need calibration. Personally, I've never used either on small M5 or M6 bolts. I use a 4-5-6 Y-style wrench and go by feel.
    The click-type wrench is fr4om Syntace and is certified to be very accurate and is guaranteed to be +/- 4% accuracy.

    You know what, I always went with feel on thes elarger bolts and will agin. My Extralite stem requires only 2.5m which is very little as well. I will snug it just enough to hold the bar.
    DIRT BOY

    "Pain is a big fat creature riding on your back. The farther you pedal, the heavier he feels. The harder you push, the tighter he squeezes your chest. The steeper the climb, the deeper he digs his jagged, sharp claws into your muscles." - Scott Martin


  14. #14
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    Smile

    Quote Originally Posted by DIRT BOY
    Bolts got stripped even though torque was lower than reccomended. I had too saw off them off.

    The stem is bac to Extralite foe evaluation. I wanted to try something different than the Ritchey 4-axis as the face plate finish SICKS donkey balls!
    I think the bolts are too soft and EL says I have a crappy TW.

    Now it looks like USPS lost it. I am having a bad week...

    The Deda SC in 120mm came in at 118g. Looks really nice on my bike.

    Another day in the life of a weight weenie. Yahoo

  15. #15
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    Quote Originally Posted by Troy16
    Another day in the life of a weight weenie. Yahoo
    LOL!
    DIRT BOY

    "Pain is a big fat creature riding on your back. The farther you pedal, the heavier he feels. The harder you push, the tighter he squeezes your chest. The steeper the climb, the deeper he digs his jagged, sharp claws into your muscles." - Scott Martin


  16. #16
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    wrench accuracy....

    Quote Originally Posted by DIRT BOY
    The click-type wrench is fr4om Syntace and is certified to be very accurate and is guaranteed to be +/- 4% accuracy.

    You know what, I always went with feel on thes elarger bolts and will agin. My Extralite stem requires only 2.5m which is very little as well. I will snug it just enough to hold the bar.
    A click-type wrench should be accurate, but they are not failure-proof. They can produce grossly incorrect torques if the internal mechanism malfunctions. Beam types are pretty much foolproof, as long as the pointer aligns with the zero mark. A beam type can be used to check the accuracy of a click type.

    Did that crack line-up with the leading edge of the stem, by chance?

  17. #17
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    Quote Originally Posted by C-40
    Did that crack line-up with the leading edge of the stem, by chance?
    I don't think so. I measured the new bar. It's 31.82. Stem 31.79

    I put the new bar in with carbon paste and tightend it by hand. It fit much smoother and seems to fit perfect.

    Thanks!
    DIRT BOY

    "Pain is a big fat creature riding on your back. The farther you pedal, the heavier he feels. The harder you push, the tighter he squeezes your chest. The steeper the climb, the deeper he digs his jagged, sharp claws into your muscles." - Scott Martin


  18. #18
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    Well...

    Quote Originally Posted by stevesbike
    maybe this is a good time to read Thomson's discussion on carbon for stems/posts in relation to hoop strength (which your pic illustrates):

    http://www.lhthomson.com/carbon_seatpost.htm
    I totally agree with Thompson's article but for MTB only. I am a big 200lb+ guy and my riding style puts lots stress on my bikes and never had a failure with carbon fiber seatposts or bars on a road bike.

  19. #19
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    Quote Originally Posted by dagger
    I totally agree with Thompson's article but for MTB only. I am a big 200lb+ guy and my riding style puts lots stress on my bikes and never had a failure with carbon fiber seatposts or bars on a road bike.
    Same hear until this crack. I use CF Bars on the MTB, but Aluminum because I am on a a HT.
    DIRT BOY

    "Pain is a big fat creature riding on your back. The farther you pedal, the heavier he feels. The harder you push, the tighter he squeezes your chest. The steeper the climb, the deeper he digs his jagged, sharp claws into your muscles." - Scott Martin


  20. #20
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    Thanks for the info DirtBoy/et all...... useful as I was looking to buy some and noticed starbike/weight weenies were showing a delivery date for early december, now I know why and why nobody else has them in stock.... well in Europe anyway

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