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Sudden Steerer Tube Failure on Canyon Endurace

  • This topic has 20 replies, 13 voices, and was last updated 6 years ago by Pilot Pete.
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  • April 12, 2018 at 8:16 pm #28366
    ad8741

    Hi All,

    Two weeks ago, the steerer tube on my Canyon Endurace CF (approximately 2.5 years old) failed without warning, which led to a nasty crash – I have a damaged AC joint as a result.

    After sending the bike back to Canyon, they have inspected the bike and informed me that the failure was due to “a worn headset bearing not turning/spinning as it should. The lack of correct rotation from the bearing caused the headset spacers to cut into the steerer.”

    I’ve posted some pictures of this at the following link:

    https://1drv.ms/f/s!AtFNSLu4w8xTgQauFwVXcglo9pPu

    I’m looking for some advice as to whether anyone has seen a similar thing happen before, and whether the explanation I’ve been given by Canyon is in any way feasible – should a worn headset bearing ever be able to cause the catastrophic failure of a steerer tube?

    Thanks,

    Adam

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  • April 13, 2018 at 2:43 pm #916923
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    ad8741
    Jimmy Ray Will wrote:
    Am I right in thinking that Canyon headset’s are tensioned by a device in the headset cap, and not via a an expander bolt pushing down on the stem as a normal aheadset?

    Yes, that is correct.

    Jimmy Ray Will wrote:
    If so, I can think of a couple of challenges. First, with no need for an expander bolt, does the lack of this mean that there is less material to tolerate the forces put through the stem / fork interface?

    Similarly, in a normal headest, does the pre-loading of the stem against spacers / headset top cap dissipate stress into a wider area?

    Looking at the pictures, the thickness of the steerer seems minimal, is there a question around the integrity of the steerer in the first place? 

    I honestly don’t know the answer to these questions – quite a few people I have spoken to have questioned the headset setup that Canyon use. However, Canyon sell an awful lot of bikes and it seems difficult to imagine they would compromise on the integrity of such a critical item.

     

    April 13, 2018 at 2:38 pm #916921
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    ad8741

     

     

     

    DaSy wrote:
    I do struggle to see quite how a headset would cause this, I would have thought it would have to be so seized, and that you would have to put so much effort into turning the bars to steer that the bike would be unrideable.

    Yes, a few others have said the same thing – I just can’t see how that would be possible, I wouldn’t have been able to ride the bike at all if it had been seized anywhere near enough for that.

     

    DaSy wrote:
    What was the state of the bearings and adjustment of it all?

    Canyon have told me that the bearings were worn, but I could detect absolutely no sign of that – there was no play, no movement back and forth under braking – nothing at all that gave me any indication of worn bearings or incorrect adjustment, etc.

    April 13, 2018 at 12:34 pm #916919
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    Jimmy Ray Will

    Am I right in thinking that

    Am I right in thinking that Canyon headset’s are tensioned by a device in the headset cap, and not via a an expander bolt pushing down on the stem as a normal aheadset?

    If so, I can think of a couple of challenges. First, with no need for an expander bolt, does the lack of this mean that there is less material to tolerate the forces put through the stem / fork interface?

    Similarly, in a normal headest, does the pre-loading of the stem against spacers / headset top cap dissipate stress into a wider area? 

    Looking at the pictures, the thickness of the steerer seems minimal, is there a question around the integrity of the steerer in the first place? 

    April 13, 2018 at 11:57 am #916917
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    hawkinspeter

    I can’t see the photo without

    I can’t see the photo without signing up for a Live drive. Think I’ll skip that.

    April 13, 2018 at 11:37 am #916915
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    Anonymous

    I have never seen this before

    I have never seen this before, but you can clearly see where grooves have been worn into the steerer at intervals that seem consistent with the headset spacers, but it doesn’t make sense to me initially though.

    Did the headset bearing and top cap not move at all? I can only see what they mean if turning the handlebars rotated the steerer, but that the seized headset stayed still and in some way managed to keep the headset spacers still with it. 

    The spacers slide down over the steerer, so shouldn’t be able to dig in and score the surface, although I have had bikes in where the expanding wedge has been seriously over-tightened and caused the steerer to bulge and jam the spacers in place.

    I do struggle to see quite how a headset would cause this, I would have thought it would have to be so seized, and that you would have to put so much effort into turning the bars to steer that the bike would be unrideable.

    I’d ask for an explanation that states what the worn bearing did to cause the marks, and say you will take it to an engineer for an independent report if they don’t supply a reason that makes sense.

     

    Edit to say that I did just think of a scenario where the headset adjustment was really loose, so the whole thing was slopping about and could cause the steerer to move back under braking etc, and with the extra space caused by the slop, the spacers could be forced into the steerer at a slight angle repeatedly.

    What was the state of the bearings and adjustment of it all?

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