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  1. #1
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    Gub/Turner/... seatposts for Dahon

    I have seen these seatposts on ebay under various names. They claim low weight and even with postage from HK to the UK they are quite cheap.

    Has anyone used one for any length of time and if so are they ok?

    I would be a bit concerned over the unusual clamp design. It looks like the saddle rails would be held on 2 quite sharp edges. With modern lightweight saddles often having hollow rails I wondered if this could cause damage.

    http://www.ebay.co.uk/itm/TURNER-Sea...item43bd969046
    http://www.ebay.co.uk/itm/2012-GUB-S...item43bd892b71

    The other option I was looking at is the pump post and possibly removing the pump mechanism. Has anyone done this and if so does it save much weight?

    thanks

  2. #2
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    I'm sure that design will shear a weaker saddle rail unless you are a really light rider.
    Sanding the edges might help, but I would just stick with some ti or crmo rails and you should be OK.
    I would be wary of aluminum rails and quite sure carbon rails would be a disaster.

  3. #3
    coprolite fietsbob's Avatar
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    Another item I've never seen before , but they look nice..

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    I've been using a GUB for about 2 months. It took more than a month to receive mine from allez-bid.

    The claimed weight is pretty accurate, saving a huge amount over the Biologic pump seatpost (around 400 g). The weight savings is of course a bit less when I factor in the pump that I now have to carry (~100 g).

    The clamp design is pretty awful. I think it's all geared toward easy manufacturing and lightweight, casual riders. As you've noted, the clamping surfaces are minimal. The lower surface (the edge of the half-cylinder) is approximately 1/8" thick. The upper surfaces are thicker, but since they're at an angle, there's still not a whole lot of material in contact with the rails. The biggest problem, however, is that an imbalance in clamping force between the front and back bolts causes the entire assembly to shift forward. The red arrow points to my biggest concern: the bolt head grinds against the seatpost just above the hole for the bolt carrier. I think this is where the seatpost will eventually break. I'll let you know when it finally happens...

    You can also see that the bolts are curved from the misaligned clamping surfaces. Tightening them makes the problem worse.

    Other than that, the seatpost is pretty flexy because the tubing is quite thin at 1.5 mm. I weigh <140 pounds so I don't normally notice flex in other seat posts.

    GUB seatpost.jpg
    Last edited by 5b00; 07-20-13 at 11:00 AM.

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    5b00, thanks for the write up. Although not very encouraging. I have also seen very similar seatposts that cost a lot more, £80+. I think the original ones are made in Taiwan and the GUB/Turner ones are cheap Chinese copies. It sounds like they may be too cheap. It is difficult to see on the ebay listings but I think the GUB and Turner ones have slightly different clamp designs in the way the bolts pass though those top 'bridges' that hold the saddle rails. I did notice that on your photo it looks like the bar that passes through the seatpost is too far forward. Could you shift it back to stop the bolt presses on the top?

    The only seatpost that seems to be available in the UK is the pump one which means paying for a gimmick pump that I don't want. Do you have a pumppost as well? If so have you tryed to remove the pump mechanism? If so how much does it weigh with that all removed?

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    I have an 2nd-gen (2008) Dahon postpump, it's 750g with the pump and 650 without, so the difference is exactly the weight of a minipump. No weight savings possible there, and the postpump is much easier to use. I guess they simply overbuilt the seatpost to compensate for heavier/taller riders.

    Now, I also have one of these lightweight seatposts on order, mine's a LitePro. You can compare the LitePro vs GUB pics below.
    T1txvhXjXvXXb3BpZ__104947.jpgGUB-Folding-bike-aluminum-alloy-seatpost-Dahon-folding-bicycle-seat-post-Ultralight-bicycle-seat.jpg

    The GUB has the bolt pin at 90 degrees to the post. The LitePro seems to have the bolt pin, and therefore the bolts, at an angle. Plus, the LitePro also seems to have a longer bolt pin. This design should prevent the bolt(s) from interfering with the seatpost tube. I'll let you guys know how it works out when it arrives.

    Another photo of the LitePro installed (not my bike/photo)
    https://secure.flickr.com/photos/ngm...7627518469011/
    Last edited by joseff; 07-26-13 at 09:55 PM. Reason: Added pic link

  7. #7
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    Quote Originally Posted by 5b00 View Post
    I've been using a GUB for about 2 months. It took more than a month to receive mine from allez-bid.

    The claimed weight is pretty accurate, saving a huge amount over the Biologic pump seatpost (around 400 g). The weight savings is of course a bit less when I factor in the pump that I now have to carry (~100 g).

    The clamp design is pretty awful. I think it's all geared toward easy manufacturing and lightweight, casual riders. As you've noted, the clamping surfaces are minimal. The lower surface (the edge of the half-cylinder) is approximately 1/8" thick. The upper surfaces are thicker, but since they're at an angle, there's still not a whole lot of material in contact with the rails. The biggest problem, however, is that an imbalance in clamping force between the front and back bolts causes the entire assembly to shift forward. The red arrow points to my biggest concern: the bolt head grinds against the seatpost just above the hole for the bolt carrier. I think this is where the seatpost will eventually break. I'll let you know when it finally happens...

    You can also see that the bolts are curved from the misaligned clamping surfaces. Tightening them makes the problem worse.

    Other than that, the seatpost is pretty flexy because the tubing is quite thin at 1.5 mm. I weigh <140 pounds so I don't normally notice flex in other seat posts.

    GUB seatpost.jpg

    Is that a Fizik saddle? I've been thinking about getting either of these seatposts and am currently using an old Fizik Arione saddle on my Dahon.

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    Quote Originally Posted by freebooter View Post
    I did notice that on your photo it looks like the bar that passes through the seatpost is too far forward. Could you shift it back to stop the bolt presses on the top?
    Nope, it just slides forward when I level the saddle. I think the design has an inherent imbalance in the front and rear clamps. The best I can do is put something between the bolt head and the big tube to prevent gouging.

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    Quote Originally Posted by ichiro_suzuki View Post
    Is that a Fizik saddle? I've been thinking about getting either of these seatposts and am currently using an old Fizik Arione saddle on my Dahon.
    Yep it's a Fizik Gobi. I need the long rails so I can compensate for the crazy virtual setback due to the forward position of the bottom bracket. The long nose helps a bit too. One of the unmentioned benefits of these seatposts is the fact that they have zero setback, allowing me to almost reproduce the same saddle-crank relationship as on my regular bikes.

  10. #10
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    Quote Originally Posted by 5b00 View Post
    Yep it's a Fizik Gobi. I need the long rails so I can compensate for the crazy virtual setback due to the forward position of the bottom bracket. The long nose helps a bit too. One of the unmentioned benefits of these seatposts is the fact that they have zero setback, allowing me to almost reproduce the same saddle-crank relationship as on my regular bikes.
    I have the opposite problem... I prefer to have more setback and I move the Fizik saddle all the way back on the rails.

  11. #11
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    Quote Originally Posted by ichiro_suzuki View Post
    I have the opposite problem... I prefer to have more setback and I move the Fizik saddle all the way back on the rails.
    This was another concern I had as the Dahon has a short reach anyway. I think I will probably order one this weekend as the price is so low and the only other option seems to be the pumppost.

    It is annoying that Dahon didn't produce a simple, light post with a standard clamp at a reasonable price. They either have heavy suspension, gimmicky pumps or a non standard clamp.

  12. #12
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    got mine for about $15. my friend went to china on business and he carried it back for me. i should have gotten 2 as i really like this seatpost. way lighter than the original dahon seat post that i used to have.
    Attached Images Attached Images

  13. #13
    New usename ThorUSA brakemeister's Avatar
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    Quote Originally Posted by freebooter View Post
    This was another concern I had as the Dahon has a short reach anyway. I think I will probably order one this weekend as the price is so low and the only other option seems to be the pumppost.

    It is annoying that Dahon didn't produce a simple, light post with a standard clamp at a reasonable price. They either have heavy suspension, gimmicky pumps or a non standard clamp.
    Thats why I have the ThorUSA loooong seatpost ... no gimmicks, just a little longer than the original

  14. #14
    Member seadragonpisces's Avatar
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    Quote Originally Posted by freebooter View Post
    This was another concern I had as the Dahon has a short reach anyway. I think I will probably order one this weekend as the price is so low and the only other option seems to be the pumppost.

    It is annoying that Dahon didn't produce a simple, light post with a standard clamp at a reasonable price. They either have heavy suspension, gimmicky pumps or a non standard clamp.
    I know, I had the same issue too, I donít like the saddle and the i-beam set up on my Jetstream.

    I wanted just a regular seatpost so I could use my new Brooks C17 Cambium.

    I ended up getting the Biologic postpump 2.0 and although it is heavy I like the fact the pump is hidden anyway and in the big scheme of things you donít really notice the weight anyway, itís all in the mind, for me anyway since my Jetstream is hardly a light bike.
    Brompton Barcelona, Dahon Jetstream EX, Bickerton

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    I am flabbergasted, perhaps even gobsmacked. I ordered one of the Turner ones from allez-bid via ebay on Monday. That was virtually the end of the working day in HK. I got an email on Tuesday to say that it had been dispatched with an estimated deliver time of 1-2 weeks. It was delivered to me in the UK on Friday morning

    I haven't had time to do much with it yet but it looks ok. I will try and take some photos and put up a review.

  16. #16
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    I thought I would put a bit more detail on the seatpost in case any one else is considering one. General impression is that it will do the job but certainly isn't a top quality item.



    The clamp has a connected bridge on the top with the bolts going in to barrel nuts. This was the main reason I chose the Turner instead of the GUB. However, you can see on the photo that one of the barrel nuts has rust on the inside. This was enough to cause problems screwing the bolt all the way in. The bolts and nuts feel cheap and I may look to replace them some time but I am not sure how easy it will be to find suitable replacements.



    The through bar is at an angle. Unfortunately I think it is a bit short so one bolt presses on the top edge of the post and the other bolt's head presses against the seatpost.



    The minimum line is 20cm up and the listing gave 20cm min insertion. This means only a 40 height. This is just enough for me but tall riders might find it a bit short despite the long 60cm length. However, the seatpost shim is not 20cm long and any seatpost below the shim isn't doing anything. This means that if you don't extend past the min line the bottom of the post could be cut off to save a bit of weight. Alternatively the min line is too conservative and the seatpost could be extended further. The scale printed on also isn't straight or central. It doesn't start from the min line and the divisions are not equal. None of that is really important but it does show the attention to detail is pretty low.



    The expensive kcnc ones and the GUB have a ridged inner surface to save weight. The Turner is straight tubing and hence weighs slightly more than the GUB. However, the tubing isn't completely even but has two sides thicker. These are roughly the back back and front of the post but they aren't aligned exactly. I don't know whether this is just badly constructed tubing that should be even or cleverly constructed tubing that has been carelessly assembled.

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