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Fork Failure Wolf SL

Last post 08-13-2008 5:44 PM by Duellist. 45 replies.
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  • 05-12-2008 5:38 PM

    Fork Failure Wolf SL

    I bought my Soloist SLC-SL in March '07 (just over a year) ridden about ~6,500 miles and yesterday the fork failed. See picture

    http://www.flickr.com/photos/pasadenatriathlonclub/2484906057/ 

    Luckily I was real close to home and going uphill a low speed.  The failure seems to be at the bottom of the headset area.  I saw a few other posts with similar problem.  Does Cervelo cover the forks failure?

    Haroon  

  • 05-12-2008 6:18 PM In reply to

    Re: Fork Failure Wolf SL

    Where is the aluminum insert?
  • 05-12-2008 7:37 PM In reply to

    • Hammertoe
    • Top 500 Contributor
    • Joined on 11-10-2007
    • Struggling up a hillside in Vermont, USA
    • Posts 71

    Re: Fork Failure Wolf SL

    I would think the first questions are...was the steerer insert properly installed and was the stack height too high.

    See discussion here:

    http://forums.cervelo.com/forums/p/638/3234.aspx#3234

  • 05-12-2008 8:52 PM In reply to

    Re: Fork Failure Wolf SL

    I'll say it again. I will not ride a carbon fork with a carbon steerer. Carbon fiber fails quickly and had you been going down hill at high speed you would have suffered probable severe injuries. If you have to back up a carbon steerer with aluminum what does that tell you about the designers beliefs in carbon by itself? More pros are going to all carbon forks but do you think they don't change them on a regular basis? "Normal" riders can't afford to do that, we just hope all those impacts don't add up to failure. 

  • 05-12-2008 9:04 PM In reply to

    Re: Fork Failure Wolf SL

    What was the stack height from the top of the bearing to the top of the top cap? Did the aluminum insert extend 10 mm below the bearing? (see the cervelo pdf below) http://www.cervelo.com/ownersmanual/WolfSLForkInstallation.pdf IMHO, the true temper forks ride excellent. The aluminum insert is superior to a big thick carbon steerer, but it comes at a cost --- namely user flexibility (measure twice, cut once, with really no room for cutting again) as well as danger of incorrect installation
  • 05-13-2008 12:09 AM In reply to

    Re: Fork Failure Wolf SL

    What insert? My LBS set up the bike. 

  • 05-13-2008 12:20 AM In reply to

    Re: Fork Failure Wolf SL

     From the looks of the picture it doesn't appear that there was an aluminum insert. Some bike shops do not install them and when the star nut is put in place it can cause a fracture from the inside of the steerer to the outside. Hardly a good practice. It looks like there are one or two spacers above the stem. Were they below at one time and then moved above? The stack height that is important is from the top of the upper bearing cap to the bottom of the stem clamp. This is usually the same as the diameter of the steerer tube. The engineers calculate that the stress on the steerer becomes too great once the spacer height is greater than the width of the steerer. It all has to do with leverage. This stack height restriction is not the same when you have an alloy or cro-moly steerer. The manufacturer has recommended heights in those cases. I would definitely talk to the shop that assembled your bike and discuss this with them.

  • 05-13-2008 2:41 AM In reply to

    Re: Fork Failure Wolf SL

    Wow, as Peter says, there doesn't seem to have been an insert installed. If this is the case then this is  pretty shocking negligence by your LBS and implies that they didn't in any way read the instructions that came with the fork.

    Carbon steerer forks are perfectly safe provided that they are installed correctly and given appropriate maintenance. Any fork which is installed incorrectly will be an risk of failure. 

    AF

    - Cervélo R5
    - Cervélo Soloist Team
  • 05-13-2008 3:25 AM In reply to

    • kervelo
    • Top 500 Contributor
    • Joined on 07-25-2007
    • 60° 24', 25° 06'
    • Posts 78

    Re: Fork Failure Wolf SL

    I think it the Wolf forks did not come with an insert before. For example, my SLT (model 2006, built early 2007) has an all carbon fork (Wolf CL), but it did not come with it; I just cut the steerer tube and installed the FSA compression plug normally. Could it be the same thing with the bike discussed here?

  • 05-13-2008 3:33 AM In reply to

    Re: Fork Failure Wolf SL

    Are you sure the Wolf CL is all carbon, I had always though that it was a carbon fork with an alu steerer. In that case an insert isn't required and it is just a case of directly inserting the star nut. 

    AF

    - Cervélo R5
    - Cervélo Soloist Team
  • 05-13-2008 3:40 AM In reply to

    • kervelo
    • Top 500 Contributor
    • Joined on 07-25-2007
    • 60° 24', 25° 06'
    • Posts 78

    Re: Fork Failure Wolf SL

    I am absolutely sure: I built the bike myself and also cut the steerer tube. Here is a picture of my fork before cutting and installation:  http://www.pinkbike.com/photo/1077457/

    It may be that the fork had an alu steerer in 2007. The latest version of the CL fork has the steerer tube made of steel: http://www.bike24.de/1.php?content=8;product=7981;group=11;page=1;ID=03f1211fee70ceaa7bfcf28a19acde48

  • 05-13-2008 5:30 AM In reply to

    Re: Fork Failure Wolf SL

    If your LBS built this bike and didn't put the alu insert in the carbon steerer, I'd go straight to Cervelo. Your LBS will immediately go defensive if you go to it. Best case they will know they screwed up, but deny it; worst case they won't know they screwed up, and will deny it.

  • 05-13-2008 9:51 AM In reply to

    Re: Fork Failure Wolf SL

    It looks like you had a lot of steerer.  Look in the broken off areas for an alum insert.  Did it brake right below your stem? When you put your fork back in properly did it brake above the frame? above the headset cap?

    This is something in the back of my mind since reading about it and starting that other thread.

    I'm not sure I'm 100% comfortable on my Wolf SL anymore as I have one of the older ones before Cervelo started gluing them in themselves and with all the conflicting instructions I'm not sure I'm safe.
     

  • 05-13-2008 10:38 AM In reply to

    Re: Fork Failure Wolf SL

    Correct - there was no alumimun insert installed by LBS.  I had one spacer inserted above the stem and one below, the failiure looks like it was below the stem, around the headset area. Not extactly sure as I havent gone back to meaure.  I really didnt want to deal with bike. I have taken the bike back to LBS to figure what they are going to do.

    Haroon  

     

  • 05-13-2008 4:46 PM In reply to

    Re: Fork Failure Wolf SL

    What is name of th LBS ?  Is it an authorized Cervélo dealer ? Seriously shocking facts...  :(
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