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  1. #1
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    Back of legs brush seatpost

    Hey all, I just got a new frame and I have run into an issue. The back of my legs rub/touch my seatpost and brush the seatpost clamp. I didn't have this problem on my other bike, but this new bike has a wider (36.6mm) seatpost clamp diameter. I am wondering if it is bike fit related (its not fat legs haha). The seatpost is set back and I am wondering if switching to a zero setback seatpost may help. Has anyone encountered this problem before? Thanks.

  2. #2
    I play for keeps
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    Same saddle?

    Is your fit setup the same?

  3. #3
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    Yeah same saddle and same setup (same saddle height and same fore/aft).

  4. #4
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    Back of my legs very light touch as well; it has not been a problem for me. Are you otherwise fit on the bike properly? Is the contact significant enough to throw off your position to rectify?

  5. #5
    Bianchi-Campagnolo
    Reputation: kbwh's Avatar
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    A zero setback post would make it worse, no?

    Does your new frame have a steeper seat tube so that your saddle is further back in the clamp than on your previous bike?
    They do anything just to win a salami in ridiculous races. I take my gear out of the car and put my bike together. Tourists and locals are watching from sidewalk cafes. Non-racers. The emptiness of those lives shocks me. It was the illest of times, it was the dopest of times. And we looked damn good. Actually the autobus broke down somewhere on the Mortirolo.

  6. #6
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    Quote Originally Posted by robmac View Post
    Yeah same saddle and same setup (same saddle height and same fore/aft).
    If this is the case a zero setback post won't do anything with the same setup, as it will only change where the post attaches to the the saddle. You would have to adjust the position of the saddle in relation to the BB.

  7. #7
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    Maybe a wider Q-factor?

  8. #8
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    Ok, I will try to mess with the saddle in relation to the BB. If I move the saddle forward and up that might help some. I will try the wider Q-factor too. Thanks for the suggestions. Any one else run into this problem? The seatpost angle is the same on both the new and old bike.

  9. #9
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    Quote Originally Posted by robmac View Post
    Ok, I will try to mess with the saddle in relation to the BB. If I move the saddle forward and up that might help some. I will try the wider Q-factor too. Thanks for the suggestions. Any one else run into this problem? The seatpost angle is the same on both the new and old bike.
    You got it forward (and up if needed) is the only way to change it. Depending on how much you are touching Qfactor could fix it, keep in mind you are touching nearer your crotch, Qfactor is at the other end, you need to move more than 2-3x at the crank to move the same at the clamp. If you have Speedplay pedals you could get a longer shaft.

  10. #10
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    Quote Originally Posted by robmac View Post
    Ok, I will try to mess with the saddle in relation to the BB. If I move the saddle forward and up that might help some. I will try the wider Q-factor too. Thanks for the suggestions. Any one else run into this problem? The seatpost angle is the same on both the new and old bike.
    If the seattube angle is the same with both bikes, the seat posts and the saddles are identical, the same saddle position on the rails and the same saddle height should give you the exact same position over the bb/pedals. (assuming the crank arms and pedals are the same.

    IF the seat posts are different, it's tough to figure the exact same saddle position without actually measuring (below). The clamps will be different and the setback might be different even if they claim they're the same.

    Get a long carpenter's level. Put the bike on a level surface (best) or at the very least, make sure the bikes are in the same position on the floor when you measure them. Hold the level in a dead-on vertical position from the center of the bottom bracket spindle (i.e. the crank bolt) up past the nose of the saddle. Measure the distance from the nose of the saddle to the edge of the level.

    This measurement should match for both bikes. IF not, it means either the saddles are not actually placed in the same position, or the seat tube angle is different. Different seat posts wont' matter for this measurement.

    If you're using different saddles, you'll have to try to make the measurement from the place you actually sit on the two saddles, which is a much less precise landmark than the nose of two identical saddles. Certainly can be off by a cm, which is a large amount when figuring fore-aft adjustment.

    IF the above are identical, it makes me wonder if the handlebars are the same. Maybe your position is changing by a cm or two because of different reach of handlebars? Stem? brake hoods? Saddle-handlebar drop? All this stuff is easy to measure in 5 minutes if you really want to get the bikes set up identically.

    Someone else mentioned Q factor if you're not using identical cranks.
    Last edited by Camilo; 04-26-2013 at 10:29 AM.

  11. #11
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    The handlebar set up is a little different, making the reach a bit shorter. I have moved the saddle forward and up and now my legs still touch the seatpost right in the middle, so at least it is not touching at the clamp. I am wondering if a tapered seatpost might help as well. Have any of you heard of or could recommend a tapered seatpost?

  12. #12
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    Quote Originally Posted by robmac View Post
    The handlebar set up is a little different, making the reach a bit shorter. I have moved the saddle forward and up and now my legs still touch the seatpost right in the middle, so at least it is not touching at the clamp. I am wondering if a tapered seatpost might help as well. Have any of you heard of or could recommend a tapered seatpost?
    How are you knees to the top tube? (wondering if you should look into wedges).

  13. #13
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    Quote Originally Posted by robmac View Post
    The handlebar set up is a little different, making the reach a bit shorter. I have moved the saddle forward and up and now my legs still touch the seatpost right in the middle, so at least it is not touching at the clamp. I am wondering if a tapered seatpost might help as well. Have any of you heard of or could recommend a tapered seatpost?
    I had a similar problem. Bought a shim for the seat tube and went with a smaller diameter seat post.

  14. #14
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    Is it a problem or just a curiosity?

    Happens on my bike too. Only issue was with shorts wearing when I had a saddle bag with the velcro around the seat post.

    I think, for me, the issue lies more with some extra insulation on my legs...

  15. #15
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    Its a problem, its very annoying with both legs touching the seatpost every pedal stroke. I'd like to find away to avoid it besides riding a different bike as it didn't happen on any of my previous bikes, at least not that I can think of. Any suggestions are still welcome. I have to push the saddle way to far forward to avoid my legs touching the seatpost.

  16. #16
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    pennstater- did the seatpost shim work for you? This post is 31.6mm, I am thinking of using a shim and going down to a 27.2mm seatpost. That might be an easy option.

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