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  1. #1
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    Dahon Mu V-clamp - how tight?

    I came home last weekend to notice that my handlepost seemed to rock left to right, but not front & back. It felt and sounded exactly like a threadless fork that's not clamped down tight enough.

    So imagine my horror when I found out that it's actually the FRAME hinge that's loose! I've never adjusted the clamp since the bike was new, and the opening-closing action remained fiddly and loose.

    Now this isn't covered by the manual, but I basically took the clamp off, loctited the threads, then reassembled the clamp and tightened it. Now when opening & closing the clamp there's quite a bit resistance at the middle of the swing due to the V-clamp hitting the frame. Past that 90-degree point and the lever swings home easily. But set the bolt any looser and the hinge won't hold steady.

    So, how tight is tight enough? I'm afraid I might damage the (soft) aluminium frame with the steel clamp if I tighten it too much.

  2. #2
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    Bump... nobody else here has fiddled with their Dahon V-clamp? Come on...

  3. #3
    pooh bear joose's Avatar
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    Hi Joseff

    I tighted my clamp last weekend (on a Curve D3).

    There is a small bolt to adjust inside the clamp. I tighted it and kept rechecking how tight the clamp was when closing it. I found that pass a certain point i couldn't close the clamp, so I loosened the bolt just a little and now it seems fine.

    Does this help?

    Ps, This was after only 2 weeks of use. I need to get some glue soon!

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    Yeah that's where I'm at. What bugs me is that "too tight I can't close the clamp" and "floppy hinge" are only about 1/4 turn apart. I'm wondering if this is true for your Curve, or my frame is busted.

    Thanks for the reply

  5. #5
    pooh bear joose's Avatar
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    I've checked mine and it's the same as yours. Either we both have busted frames or the hinge is just a bad design?

    I'm feeling that its poor design as what is the manual doing telling me to glue my bike? I would prefer a proper engineered solution.

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    Quote Originally Posted by joose View Post
    I've checked mine and it's the same as yours. Either we both have busted frames or the hinge is just a bad design?

    I'm feeling that its poor design as what is the manual doing telling me to glue my bike? I would prefer a proper engineered solution.
    This is the sort of thing that is covered in the first service - lots of parts of the bike are going to need adjustment as they bed in over the first 100 miles or so. It is usually made plain to bike buyers that they should expect the need for such adjustments in the early stages.

    I'm curious, were you told this and why didn't you take it to the dealer to be fixed?

    That "glue" is thread lock and it is a proper engineered solution.

  7. #7
    pooh bear joose's Avatar
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    This is the sort of thing that is covered in the first service - lots of parts of the bike are going to need adjustment as they bed in over the first 100 miles or so. It is usually made plain to bike buyers that they should expect the need for such adjustments in the early stages.

    Nothing at all was said to me about adjustments when I got the bike. The guys didn't know how to fold it and most things were loose ie the fenders and rack.

    I'm curious, were you told this and why didn't you take it to the dealer to be fixed?

    For everybody in the UK I only have to say the bike was from Halfords.

    Outside the UK, read the following reasons why I won't take it back to my dealer.

    I could take the bike back as is my right, however they took two months to order my bike only to have ordered the wrong one. My bike was available all the time and only took two more days for them to order it in. They wouldn't fit a wireless computer as 'catch' them once and they're broken forever, oh and slime tubes are impossible to cut down from 20" to 16". Both these jobs where meant to be done during the first setup and I would imagine would be a little more work.. which I'm sure had nothing to do with it? My main hinge was really loose at first but I didn't realise until I visited a LBS who warned me that the bike was totally unsafe to ride until that was tighted up there and then. Which as a newcomer to folders I rely on my dealers staff to sort this out and give me basic lessons. I simply don't trust their poor advice and slow sloppy service.


    That "glue" is thread lock and it is a proper engineered solution.

    Technically yes, but I've fallen foul of the not looking at my instruction manual which I'm sure 99% of people do. Perhaps if my dealer had explained I would be more happy but I've had to find out by riding a dangerous bike and being lucky enough that a LBS pointed it out for me.

  8. #8
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    Quote Originally Posted by joose View Post
    ...For everybody in the UK I only have to say the bike was from Halfords....
    'nuff said!

    I suspect it is a big mistake for manufacturers of folders to let their bikes be sold by the mass marketers.

    Almost all folders have specialised bits but the customer blames the manufacturer, not the dealer, when these give problems when they are not setup or adjusted correctly.

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    I bought my Mu from a chain store, Rodalink. While it's not a big box store like joose's, I'm sorry to report that their mechanics are not very familiar with Dahons, nor do they stock parts.

    Yes I did bring my bike in for "first service" after about 300km and they adjusted the Neos derailleur (correctly) and brakes (INcorrectly). Specifically, my front wheel had a bad dish, and instead of truing the wheel they adjusted the V-brake to match the misalignment of the wheel. Other than that, they DIDN'T TOUCH the hinges. Neither the frame hinge, nor the handlepost hinge. I had NO IDEA that they needed to be checked/adjusted after such a short distance.

    Much later on, I brought my bike to an LBS that carries the Strida, Carry-Me, Hasa and Oyama as well as Chinese Dahon Speed and Boardwalks. Safe to assume they're well-versed in hinged foldies. They spotted and fixed the wonky wheel, but did not touch the hinges either. 200kms later I then had the episode I posted above.

    How's that for product experience?

  10. #10
    pooh bear joose's Avatar
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    That "glue" is thread lock and it is a proper engineered solution.

    Thinking about this and wonder why there cannot be a plastic insert that fills the space to stop the bolt unscrewing. This could be made to be unclickable for when you want to remove it. I think this would be a more 'elegant' proper engineered solution.

    Simple minded riders like myself would not really be aware of it and not need to be. Advanced riders could remove if needed? Although I can't think why you would want to, its ever tight as it should be or not

  11. #11
    PDR
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    My MU SL is going back to the dealers this weekend as it has developed a problem with the hinge.
    With mine it has movement up and down rather than side to side. In other words I can hold the seat and handle bars and move them back and forth and see the play in the hinge.
    I know you can adjust the tightness of the clamp but this does not cure the problem I have.

  12. #12
    pooh bear joose's Avatar
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    Thats the same type of play I have if the bike is not fully adjusted.

    Is this worse than side to side play?

  13. #13
    PDR
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    I did try adjusting the hinge but it made no difference.
    Having examined the hinge I can see that a solution would be to pack the hinge pin with shim washers. I could probably fix the hinge myself but having paid good money for a bike that is only 4 months old, I don’t see why I should, hence the reason it is going back to the dealers this Saturday.

  14. #14
    pooh bear joose's Avatar
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    Hmm

    I may take another look at my bike and consider my options? I wonder if they would let me swap it for
    a D7?

  15. #15
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    I'm resurrecting this thread; I picked up a second-hand Curve, I think it's the 2009 model, and I have the same problem with the V-clamp. There's significant play unless I tighten the clamp such that it takes what seems like slightly excessive force to close it (I've lubed the moving parts). . . I've not looked at how the hinge is constructed yet. . . perhaps there's something there that needs tightening?

    How did you guys resolve this issue?

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    Here's the service instructions (with details on how to tighten the hinge, torques etc...): http://www.dahon.com/sites/default/f...ions_en_12.pdf

  17. #17
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    According to that I have the version B clamp. Hmm, seems I've done all I could have done already and there's still some play. There's no mention of the hinge in the instructions, just the clamp; I wonder if the hinge itself requires some adjustment.

  18. #18
    PDR
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    Ahhh I see that I replied to this thread way back when I had my first Dahon MU SL.... that frame hinge wore and so did that of the replacement bike.... I'd never personally buy another Dahon but that is just my own opinion. After all the trouble I went out and bought a Titanium S-Type Brompton...whichI wanted in the first place but got drawn towards the MU SL after test riding one.

    One of the many good things about the Brompton is the clamp design and the fact that you screw up the clamp with a big wing nut style lever so the clamp is always tightened to a consistent torque. With this design the clamp is alway tight so there is no way for the clamping mechanism to wear.

  19. #19
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    I'm always hesitant to criticize in case I've misunderstood something but it appears to be a design issue. My 2007 Dahon vise-grip thingy works great, no problems with that.

  20. #20
    Senior Member neilfein's Avatar
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    Quote Originally Posted by chagzuki View Post
    I'm always hesitant to criticize in case I've misunderstood something but it appears to be a design issue. My 2007 Dahon vise-grip thingy works great, no problems with that.
    I love my Curve, but the frame hinge needs a lot of attention over time. I learned this when I was riding a couple of years ago and happened to look down, and saw that the thing that holds the clamp open was gone. I made it to my destination, but that was scary!

    Frame clamps are, I think, not a design flaw but an intentional compromise, and most sub-1k foldiers seem to use them. Bikes that don't use a frame hinge can handle better, but this is at the expense of a larger folded size. (Although Brompton manages to have a small folded size and has no frame hinge.)
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  21. #21
    PDR
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    Quote Originally Posted by neilfein View Post
    I love my Curve, but the frame hinge needs a lot of attention over time. I learned this when I was riding a couple of years ago and happened to look down, and saw that the thing that holds the clamp open was gone. I made it to my destination, but that was scary!

    Frame clamps are, I think, not a design flaw but an intentional compromise, and most sub-1k foldiers seem to use them. Bikes that don't use a frame hinge can handle better, but this is at the expense of a larger folded size. (Although Brompton manages to have a small folded size and has no frame hinge.)
    Sorry to say but you are wrong on this point.... the Brompton does have a hinge on the main frame tube.

  22. #22
    Senior Member neilfein's Avatar
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    I see... right behind the handlebar post. I guess only Bike Friday got it right!
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  23. #23
    It's got electrolytes! chucky's Avatar
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    Quote Originally Posted by neilfein View Post
    I see... right behind the handlebar post. I guess only Bike Friday got it right!
    No frame hinge on any of Pacific Cycles' bikes either (Carryme, Birdy, IF). Far and away the best engineered folders in the market IMO.

    Bike Friday, well...don't amateurs make bikes out of Cromoly?
    Last edited by chucky; 10-31-10 at 11:15 PM.

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