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  1. #1
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    N-Gear Jump Stop Chain Guide what size clamp to order

    there is 3 clamp sizes 31 28 and 34 how can i be sure what size to order i think its a 31.8 but not sure,

    its a 2011 trek ex7

  2. #2
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    specs say my seat post is a 31.6, does that mean the 31.8 will work?

  3. #3
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    107 people on this forum right now someone has to know, ive been trying to figure this out for over an hour now

  4. #4
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    Im not to familiar with the n gear.. Doesn't it mount in place of front deraileur? If so look up the clamp size for that. I believe the seatpost is measured by inside diameter of seat tube / outside diameter of seatpost....

  5. #5
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    Yes the 31.8 clamp will fit on your Trek based on the 31.6 seat-tube diameter....but I would not use the n-gear chain stop on a full suspension bike.......I had it on a 4 inch travel Giant NRS with the same 4-bar suspension as the Trek and the chain would fall off during maximum compression of the shock (the chain would move up past the chain-stop so it would fall over it and then to the inside.

    I imagine it will be worse on the 5-in travel EX 7...the plate on the n-gear is just on tall enough to account for the amount of vertical travel that your chain goes through as the shock cycles through its travel.

    The other problem I had was the clamp was made from reall flimsy plastic and it would sometimes rotate when the chain got jammed and then I had to readjust it every single ride.

    If you are thinking of going 1X or 2X I would look for a chainguide from E13 or MRP or similar...
    Last edited by osmarandsara; 09-21-2011 at 11:21 PM.

  6. #6
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    i think i will go with the high seat tube mount chainguide from mrp

  7. #7
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    Quote Originally Posted by osmarandsara View Post
    Yes the 31.8 clamp will fit on your Trek based on the 31.6 seat-tube diameter....
    This isn't true...that would mean the the seat tube walls are only 0.1mm thick.

    Generally speaking, a bike that uses a 31.6mm seat post will have a 34.9 outside diameter.

  8. #8
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    ^^ Correct.

    You need the OD. I found this out the hard way. Doh.
    If you goto N-Gear's site, there are instructions on how to measure.

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