Dropper Post length question

Forums Mountain Bike Forum Dropper Post length question

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    • #212790

      I’m sure this topic has beat into the ground but please don’t flame me. Yes, Ive used the search bar to no avail. I checked MTBR and others as well as the google machine. I digress, My rig has a 400mm post. It is a max insertion and sits right where I need it. However, I cant drop my post down for downhill or slope style shenanigans. If I run the 380mm dropper I could just simply adjust the insertion amount out to achieve what I need to achieve pedal position correct. Currently at max insertion my stack height is at 80mm. So 320mm inserted into the tube. a 380mm dropper would be able to achieve that same height with 100mm of travel. If my math is correct I’m running the post 2omm shorter but the 100mm of travel would equate to the factory seat post postion correct-o-mundo? Technically I’m taking the bottom end out and adding to the top end via adjustable dropper.

    • #212797

      Thats a lot of numbers but I think I understand the situation.

      The 380mm post will work as far as the length of your seat tube. But, it sounds like the seat will end up being too tall for you. If you currently have an 80mm stack height, with a 100mm dropper you’re going to have a minimum of 100mm extending above the seat tube, plus even more to account for the bumpout nub.

      • #212810

        Thanks for responding Jeff. I measured wrong last night. I actually have 160mm plus rails and seat exposed. Soooo ill just insert post to achieve 160 at the top and enjoy the radness of my dropper. Amazing how clear things get when you take proper measurements.

    • #212821

      Sweet, sounds like it’ll work!

    • #212924

      @jtirwin27 Would it be possible for you to take a pic of the exact measurement you took to determine the length of the Dropper post? I have a friend wanting to install one on his seat post now and we’re not exactly sure if a 125mm or 150mm will suffice. I was told to measure from the saddle rail down to the top of the seat post collar but, I’m questioning if that is correct or all we need to know here.

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