Fizik Carbon Braided Rails Issue

rich_e
rich_e Posts: 389
edited August 2013 in Workshop
About a month ago I bought a Fizik Aliante, the version with carbon braided rails. I tried a few different saddles before I got to it and am really happy with it.

I'm using it with a Bontrager basic carbon seat post which I purchased Bontrager's oversized seatpost ears for, which replace the original ears and are designed to hold larger oval rails.

It still takes a bit of squeezing to get the rails into the seatpost ears due to a larger section of 'wrap' which I assume is designed to protect the carbon underneath it where it gets clamped by the seatpost. I don't know what this 'wrap' material is, but its quite brittle.

So to the point, given that this is the first saddle I've had with carbon rails, I think I was probably a bit cautious about tightening it up to much, so I probably hadn't tightened it sufficiently. The oversized ears say to use a maximum of 16Nm, but I don't have a torque wrench.

I was riding last weekend when I hit a pothole or something at speed while seated. This jerked me and caused the saddle position to move, so that the nose was now pointed upwards somewhat, presumably because it was not tightened sufficiently enough.

When I got home, I noticed that the brittle wrap material had actually cracked on both sides, which effectively would have also accounted for loosing the tightness to the seatpost as well.

My question really is as to whether this cracked wrap is really any danger?
I've covered it up with electrical tape which has brought it more flush.
I must also point out that there is nothing wrong with carbon rails themselves underneath the wrap. Is this wrap simply just there to protect the carbon?
Anyone with a Fizik saddle with carbon rails had the same?

Some pictures below:

IMG_2313.JPG

IMG_2314.JPG

IMG_2315.JPG

Comments

  • sungod
    sungod Posts: 17,334
    are you sure it was cracked, rather than cut by the clamp...

    not familiar with the post/clamp, but from pictures it looks like one that clamps from the side rather than one where the rails are supported on a horizontal rest with a clamp on top

    under impact i think the rails will get rammed down a smidge, that would dramatically increase the side force from the clamp, maybe enough to cut the wrap

    in the first image it looks like there's a pinch mark on the side of the rail above the cut area, that also seems to fit with the rail being squished by the clamp

    fwiw i've used a fizik saddle with similar rails, had plenty of bumps, never any sign of damage to the wrap, but this was with a normal top-bottom clamping seatpost
    my bike - faster than god's and twice as shiny
  • Monty Dog
    Monty Dog Posts: 20,614
    I suspect the outer wrap is sacrificial - it's definitely not structural. If there's no cracking and creaking when riding, I'd carry on.
    Make mine an Italian, with Campagnolo on the side..
  • ugo.santalucia
    ugo.santalucia Posts: 28,310
    If you can return it under warranty and get your money back, that would be a good thing. Every engineer will tell you that clamping carbon fibre is not a good idea, yet the industry make these things for the ultimate weigh saving... in my view they are not fit for purpose and should not be purchased... if that rail fails, you might look at a long time off the bike
    left the forum March 2023
  • rich_e
    rich_e Posts: 389
    Sungod you are correct, its a side clamping mechanism on the seatpost.

    I'm not really sure whether its been cut or cracked, the wrap just seems to be made of such a brittle material that I figured it probably just broke under force.

    I bought it from Wiggle and they are pretty good at returns, so presumably I could send it back. Doing the Ride London next week though, so don't really want be sending it away until after I've done that.

    Would getting a different seatpost be a better idea if they are better off with top/bottom clamping.
  • sungod
    sungod Posts: 17,334
    if the rails aren't visibly marked, deforming, or making any noise under full weight then probably just the wrap is damaged, i've used cf rails for years with no problems

    but, yes, i'd consider changing the post for one with a more suitable clamp
    my bike - faster than god's and twice as shiny
  • racingcondor
    racingcondor Posts: 1,434
    From what I've read the wrap is just there to add friction against the clamp.
  • denniskwok
    denniskwok Posts: 339
    Yes, the wrap is there to add grip to the champing surfaces, so you don't have to torque down on the carbon rails too hard. It's not really structural.
  • careful
    careful Posts: 720
    Had a similar issue with mine a couple of thousand miles back. The only thing I did was to make quite sure that any sharp edges on the clamp were filed/sanded smooth. No problems since.
  • mallorcajeff
    mallorcajeff Posts: 1,489
    Min was the same after 2000 miles. A year later with 15000 miles on it, its still fine. Carry on.
  • rich_e
    rich_e Posts: 389
    Thanks guys.

    I actually went with Fizik's own Cyrano Carbon seatpost.
    Looks really nice and it clamps down with a much wider surface area. No slipping and I also bought a torque wrench to make sure I was clamping it correctly.
  • tonye_n
    tonye_n Posts: 832
    Monty Dog wrote:
    I suspect the outer wrap is sacrificial - it's definitely not structural. If there's no cracking and creaking when riding, I'd carry on.
    Do you mean superficial?

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