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Oneup Compnents Dropper Design

bossnutevobossnutevo Posts: 15
edited September 2018 in MTB workshop & tech
I’ve just purchased a dropper post from OneUp Components and have been puzzling on how it works. The cable inner is held at the actuator at the bottom of the post and can’t move. Instead the cable sheath end cap moves and this depresses the dropper mechanism. I can’t see how this can work as it relies upon slack in the cable sheath. On my bike the cable exit point in the seat stem traps the cable sheath meaning it cannot move thus rendering the dropper post useless. As I’ve attempted to install the post I can’t send it back, so unless I’ve misunderstood the operation of it then I’m stuck!
Help!

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  • slc123slc123 Posts: 407
    bossnutevo wrote:
    I’ve just purchased a dropper post from OneUp Components and have been puzzling on how it works. The cable inner is held at the actuator at the bottom of the post and can’t move. Instead the cable sheath end cap moves and this depresses the dropper mechanism. I can’t see how this can work as it relies upon slack in the cable sheath. On my bike the cable exit point in the seat stem traps the cable sheath meaning it cannot move thus rendering the dropper post useless. As I’ve attempted to install the post I can’t send it back, so unless I’ve misunderstood the operation of it then I’m stuck!
    Help!

    I am not entirely sure what you mean, generally the internal cable will be connected to the actuator at the bottom of the post, this is then routed internal through a cable out and up to the lever on your bars. You will then need to get the right cable length and cable tension, so that when you squeeze the dropper lever you are essentially tightening the inner cable and pulling down the actuator. The post is then free to drop under your weight, release the lever and the post will stay dropped. Remove your weight and re-engage the lever and the post will rise.

    The outer cable housing has nothing to do with the actual mechanics of the dropper, it's just to protect the inner cable.
    Cannondale Trail 27.5 | 2015
    Titus El Chulo 27.5 | 2017
    Trek Slash 9 27.5 | 2015 (building)
  • JBAJBA Posts: 2,625
    Have you read the INSTALLATION INSTRUCTIONS?
    It all seems pretty straightforward. A quick Google search doesn't reveal any other reports of the problem you are having.
    “Life has been unfaithful
    And it all promised so so much”

    Giant Trance 2 27.5 2016 ¦ Bird Zero Mk1 ¦ Giant Revolt Advanced 2 2019 ¦ Giant Anthem 3 2015 ¦ Specialized Myka Comp FSR 2009
  • slc123 wrote:
    bossnutevo wrote:
    I’ve just purchased a dropper post from OneUp Components and have been puzzling on how it works. The cable inner is held at the actuator at the bottom of the post and can’t move. Instead the cable sheath end cap moves and this depresses the dropper mechanism. I can’t see how this can work as it relies upon slack in the cable sheath. On my bike the cable exit point in the seat stem traps the cable sheath meaning it cannot move thus rendering the dropper post useless. As I’ve attempted to install the post I can’t send it back, so unless I’ve misunderstood the operation of it then I’m stuck!
    Help!

    I am not entirely sure what you mean, generally the internal cable will be connected to the actuator at the bottom of the post, this is then routed internal through a cable out and up to the lever on your bars. You will then need to get the right cable length and cable tension, so that when you squeeze the dropper lever you are essentially tightening the inner cable and pulling down the actuator. The post is then free to drop under your weight, release the lever and the post will stay dropped. Remove your weight and re-engage the lever and the post will rise.

    The outer cable housing has nothing to do with the actual mechanics of the dropper, it's just to protect the inner cable.


    The key to all this is the fact that the cable inner is attached to a fixed part of the dropper which does not move. The bit that moves is a sleeve operated by the cable outer. Honest.
  • figbatfigbat Posts: 680
    Can your frame cable exit hole be modified? Is there a grommet that could be trimmed/removed/replaced?
    Cube Reaction GTC Pro 29 for the lumpy stuff
    Cannondale Synapse alloy with 'guards for the winter roads
    Fuji Altamira 2.7 for the summer roads
    Trek 830 Mountain Track frame turned into a gravel bike - for anywhere & everywhere
  • figbat wrote:
    Can your frame cable exit hole be modified? Is there a grommet that could be trimmed/removed/replaced?

    I wondered that; but looks like the bottom of the seat stem is sealed because of the bottom bracket. I assume the manufacturer thinks you will have some free slack in the sheath and it is unconstrained. The exit hole in my frame almosts links the cable and holds it in place, it cannot move as it needs to
  • JGTRJGTR Posts: 1,404
    edited September 2018
    https://www.mbr.co.uk/news/product_news ... per-374372

    I see exactly what mean, when actuated the cable needs to move approx 5-10mm which it won’t do if it’s taught
  • JGTR wrote:
    https://www.mbr.co.uk/news/product_news/oneup-dropper-374372

    I see exactly what mean, when actuated the cable needs to move approx 5-10mm which it won’t do it’ll taught


    YES!!!!! Thought I was going mad.
    I just had an email from OneUp Components who said:

    Hey David, yes there is a minimal amount, 4mm of movement that the cable housing needs to move in order to actuate our post. You will need to ensure there is a little slack in the housing in the frame and not pulled completely tight.

    I'm a bit stuck now (no pun intended) - I can't return the dropper post because I have tried to install it, it isn't faulty either. So I need to try and make it work.
  • JBA wrote:
    Have you read the INSTALLATION INSTRUCTIONS?
    It all seems pretty straightforward. A quick Google search doesn't reveal any other reports of the problem you are having.


    Yes I have read the instructions and watches various videos.
    OneUp has confirmed what I thought.
    Just need to try and make it work now in my bike.
  • bossnutevo wrote:
    JGTR wrote:
    https://www.mbr.co.uk/news/product_news/oneup-dropper-374372

    I see exactly what mean, when actuated the cable needs to move approx 5-10mm which it won’t do it’ll taught


    YES!!!!! Thought I was going mad.
    I just had an email from OneUp Components who said:

    Hey David, yes there is a minimal amount, 4mm of movement that the cable housing needs to move in order to actuate our post. You will need to ensure there is a little slack in the housing in the frame and not pulled completely tight.

    I'm a bit stuck now (no pun intended) - I can't return the dropper post because I have tried to install it, it isn't faulty either. So I need to try and make it work.


    Note he said CABLE HOUSING and not CABLE INNER
  • figbatfigbat Posts: 680
    Can the housing be thinned down at all? Just in the area that goes through the frame?
    Cube Reaction GTC Pro 29 for the lumpy stuff
    Cannondale Synapse alloy with 'guards for the winter roads
    Fuji Altamira 2.7 for the summer roads
    Trek 830 Mountain Track frame turned into a gravel bike - for anywhere & everywhere
  • figbat wrote:
    Can the housing be thinned down at all? Just in the area that goes through the frame?

    Maybe, it's standard gear cable sheath and is pretty inflexible.
    This is going to be tricky!
  • JGTRJGTR Posts: 1,404
    I thinks you’d have good grounds to return it if you really wanted to. How could you know that it wouldnt be compatible without fitting it unless it was clearly stated that the cable must be able to move in the instructions?

    Could you not just push a bit more cable into the seat tube so there is some to move? Would only need a sight bend inside the seat tube?

    Will be interested to hear what it’s like if you can get it to work, want one for mine as you can change the amount of drop so you can get post right into the seat tube the seat right down as far as possible.
  • JGTR wrote:
    I thinks you’d have good grounds to return it if you really wanted to. How could you know that it wouldnt be compatible without fitting it unless it was clearly stated that the cable must be able to move in the instructions?

    Could you not just push a bit more cable into the seat tube so there is some to move? Would only need a sight bend inside the seat tube?

    Will be interested to hear what it’s like if you can get it to work, want one for mine as you can change the amount of drop so you can get post right into the seat tube the seat right down as far as possible.


    I think there should be room to push some slack into the seat-tube because the dropper is really well made and user serviceable. I do want it to work but was really surprised they decided to engineer it in this way - probably so that they can keep the post length short. I'll let you know how I get on - hopefully posting some pictures.
  • slc123slc123 Posts: 407
    Never seen that setup on a dropper. They can’t really sell it as a universal fit for stealth running if it means you have to come up with bespoke modifications for your bike or the dropper to fit. I would probably return it and get something else.
    Cannondale Trail 27.5 | 2015
    Titus El Chulo 27.5 | 2017
    Trek Slash 9 27.5 | 2015 (building)
  • slc123 wrote:
    Never seen that setup on a dropper. They can’t really sell it as a universal fit for stealth running if it means you have to come up with bespoke modifications for your bike or the dropper to fit. I would probably return it and get something else.

    I've made many attempts today to try and get this to work but there is simply not enough slack in the cable to actuate the dropper. I don't think a 'standard' internal dropper (one in which it is activated but the cable inner instead of the sheath) would be a problem. Actually I'm quite sad as the build quality and the idea of custom heights is good, but it simply doesn't fit in my bike. Now have to go into battle to get a refund as I've had to try and install it - with all the resultant scratches on the post - in order to prove it doesn't work as there is no way to bench test it. Let's see how I get on....
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