WCS One-Bolt Seat Post Slipping
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  1. #1
    tka
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    WCS One-Bolt Seat Post Slipping

    I have a new WCS Alloy One-Bolt seat post with a Sella Italia SLR saddle with Vanox rails. Every time I've ridden the bike the saddle has slipped. I start the ride with nose of the saddle 2-3mm low, by the time I finish the nose is 10-15mm high. The bolt is torqued to 12 NM as spec'd, and after the ride it is still torqued to 12 NM. The saddle hasn't moved forward-back any, just the angle keeps slipping. Any ideas on how to stop the angle from slipping? Liquid Torque?

  2. #2
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    Honestly, I never had luck with my Ritchey 1-bolt seatpost. Like yours, it kept slipping. I got disgusted with it and threw it out.

    One bolt posts that rely purely on compression and friction just don't make sense to me if you want a secure connection. I tried the Ritchey because I liked his other products such as his stems. The posts must work because he offers 15 different models with a one-bolt attachment; both of us must be doing something wrong...

    Personally, I'd keep increasing the torque until either the slipping stopped or the post broke, then I'd throw it out. I'm sure you don't want to follow my advice.

    As an alternative, post your question directly to Ritchey Design (they've answered my questions when I called them) or post your question directly to the Ritchey Rep on this forum. He checks in periodically.

    For what it's worth, I replaced my slipping Ritchey post with a Zipp Service Course. The two-bolt design with threaded adjustment can't possibly slip, which is why I bought it.

  3. #3
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    I had a WCS 2-bolt seat post on my previous bike. (My new bike has a different diameter post.) There is a bolt on each side clamping a top piece to the curved surface on the seat post itself. I had a similar problem, the seat would shift suddenly when I hit a big bump.

    The curved surfaces already had a slight texture in them, but I used 180 or 220 wet-and-dry sandpaper to scuff it more, especially in lines across the direction of movement. And I had a tube of carbon assembly paste (Tacx), a gel with some fine plastic grit in it. I smeared the surfaces with the gel before putting it back together. I was careful not to sand it much at all, because it's too easy to sand down depressions into aluminum.

    (As I remember, the curved mating surfaces showed much more wear at a few areas, showing that they didn't completely fit together. So those smaller patches were taking much more of the load than the rest. I sanded those high spots a little more, so the rest of the clamp would fit better. It should have been more accurately cast/stamped/machined when it was made.)

    That fixed it. I rode it for years with no problems. You'd think that Ritchey would have solved those problems by now.
    Last edited by rm -rf; 03-21-2015 at 07:34 PM.

  4. #4
    tka
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    Quote Originally Posted by rm -rf View Post
    I had a WCS 2-bolt seat post on my previous bike. (My new bike has a different diameter post.) There is a bolt on each side clamping a top piece to the curved surface on the seat post itself. I had a similar problem, the seat would shift suddenly when I hit a big bump.

    The curved surfaces already had a slight texture in them, but I used 180 or 220 wet-and-dry sandpaper to scuff it more, especially in lines across the direction of movement. And I had a tube of carbon assembly paste (Tacx), a gel with some fine plastic grit in it. I smeared the surfaces with the gel before putting it back together. I was careful not to sand it much at all, because it's too easy to sand down depressions into aluminum.

    (As I remember, the curved mating surfaces showed much more wear at a few areas, showing that they didn't completely fit together. So those smaller patches were taking much more of the load than the rest. I sanded those high spots a little more, so the rest of the clamp would fit better. It should have been more accurately cast/stamped/machined when it was made.)

    That fixed it. I rode it for years with no problems. You'd think that Ritchey would have solved those problems by now.
    I followed what you did and after 5 rides the saddle was still in position. I needed to make a little adjustment on the saddle so I loosened it up, made the adjustment, and torqued it back to 12 Nm, and the first ride after it slipped again. Although this time is moved nose down that nose up, but it still slipped. I'm getting tired of this, might need to look at another seat post to replace it.

  5. #5
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    WCS One-Bolt Seat Post Slipping

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    Last edited by mfdemicco; 06-06-2015 at 11:12 AM. Reason: edit

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