Complain to the BBB or to ASTM Subcommittee F08.10. The BBB will take care of shoddy customer service and make Dahon jump through many hoops to maintain good standing, assuming the claims against them are legitimate. ASTM Subcommittee F08.10 is comprised of industry leaders (all bicycle manufacturing major players) that have created regulations on what force testing a bike must withstand and standard equipment a bike must have to be considered safe. The CPSC might even have something to say about this problem. When something's sh#tty, make the company fix it by alerting the people that can force them to or else! Dahon's too big to not have to deal with this (read lawyers would love the case) if this is a legitimate safety concern/design flaw. Welcome to popularity and success, Dahon! Here's your lawsuit.

Proof of safety issue with handlepost
 

It seems anyone who works for Dahon rhymes off the same jargon each time confronted with a safety issue. Whilst cycling my Dahon Courser which was barely a year old, a section of the clamp that holds the handlebar in place snapped off causing me to lose control of the steering. Thankfully, I wasn't going fast and didn't injure myself, however it could have been a different story. I have lost faith in Dahon since this occured as I have simply been fobbed off due to the bike being outside its warranty. It is simply unacceptable at the lack of help that I received with no one willing to take the blame for what was clearly a design/manufacturing fault. Trying to get a replacement part is even more of a nightmare and quite frankly I feel I shouldn't have to do or pay for myself. I urge any other Dahon users with similar faults to come forward with their complaints. Paying £300 for a bike that gets average use, maintained well, stored indoors etc, I don't expect to have to replace half the parts the following year.

The spare parts thing is a massive problem in the UK. With exchange rates as they are it's probably no more expensive to order from the US where parts are easier to come by, but if the £ devalues any further it'll become too expensive.

There is an inherent design challenge with long-riser and telescoping handlebars, in that when riders pull against the handlebars to gain pedaling leverage, e.g. when climbing, the riser receives quite a lot of force, and flexes slightly. Repetitive flexion over time can lead to metal fatigue and failure. The diameter and gauge of the riser have to be increased to prevent the flexion. Forces are also applied to the stem.

Thor alludes to this issue, though placing responsibility on the rider's shoulders rather than on the design itself, when he remarks that riders learn to "spin" -- use their legs, not their arms:Regards
T

not alluding at all ... just the facts .. if you pull on the handlebars like mad, you will be able to recognize flex and when the quick release is not tightened by spec than it will loosen up... this is all in the manual and all over the place... it is not new ....

learn to sit down and spin and treat the bike with respect.
check the bike before you ride it, if you dont know what you are doing, bring the bike to a dealer who does ... and on and on and on

you will be faster and the bike will last forever
nothing alluding to this .......experienced based knowledge......yes ... .......
maybe not to everybodies liking ....certainly not marketing driven

thor

I'm not suggesting this is anything new or subtle; rather, it's quite obvious: the long-riser design acts like a lever when the handlebars are pulled on with force. Some makers deliberately avoid long risers. Those who do use them are refining their designs.

Although I agree with you that it's bad riding form to pull on the handlebars "like mad" as you say, and that riders should use their leg muscles, it is simply not enough to advise the consumer that pulling on the handlebars is a no-no. Properly designed, a long riser (and stem and hinge) will be robust and rigid enough not to flex when subjected to such forces, because there is the real possibility of severe injury should the steering assembly fail.

Regards
T

Interesting that this discussion was brought up. In my tikit review, I mentioned that my Dahons' "adjustable handlebar stems and handlebars slip and rotate in hard riding unless their quick-releases are unreasonably tight." In truth, I was being very gentle on Dahon here -- it's rather worse than that.

Specifically: I own three Helios P8s. ALL THREE have the same problem: after riding about, rather *mildly* I might add, the handlebar stem tends to pop and rotate about 15 degrees clockwise on me, even when the quickrelease is pretty tight. That's the most it can rotate because of the dimple in the stem. But rotate it does. And it is most certainly is a safety issue. At the very least it's an enormous irritation.

Thinking this might just be a Helios issue, I've test-ridden a brand-spanking new 2008 Mu P8 at Mt. Airy Cycles (a great shop). During a mild ride, pop! Same problem.

The solutions suggested here are not a reasonable long-term solution: they mostly involve preventing the handlebar stem from being moved about. But there is a height interval in which you MUST move the handlebar stem (up/down) in order to fold the bike because otherwise it interferes with the attachment of the magnets. So the semi-"permanent" solutions, IMHO, are only workarounds for people of the right height.

I have also found that the handlebars themselves tend to slip occasionally, rotating in your hands, even when the quickrelease is pretty tight. This happens in more heavy riding granted, but it is of some safety concern as you lose control of the handlebars, yeesh.

I have a Helios P8 and a Helios XX Limited Edition .. both from 2004.. both with the adjustable height steerer... neither have ever given me any handlebar related problems through the years..

Did you happen to read of the Tickit seatstay frame break as reported on the Friday list?

"Hi guys. I just had a pretty scary thing happen. I was riding to the
gym earlier this evening and I went over a bump...not a pot hole, just
a bump. I heard a loud pop and thought that I might have blown a tire
or something. The tire seemed ok, so I continued to ride for about
ten feet when I noticed something was really wrong, the frame felt
wobbly. I immediately stopped. I made an inspection of the bike and
I noticed that one of the arms that connects the seat post to the rest
of the frame had sheared into two parts very near the point that this
arm is welded to the seat post. If you are seated on the bike it is
the arm that is on the left side which does not curve like the other
one does to fit around the main horizontal tube.

I purchased the bike in January and am really pleased with it because
I use it to commute to work everyday. It has performed flawlessly for
the most part with the exception of some minor shifting issues. This
frame failure was a real shock though. I'm wondering if this has
happened to anyone else? This particular arm failed at just below the
point where it seems robustly welded to the seat post, so I'm
wondering if this is perhaps a design flaw.

At any rate, I'd like to hear if anyone has experienced this problem."




All bikes are subject to unforeseen problems. Dahon seems to get the lion's share complaints, but they also sell the lion's share of bikes. As all reputable manufactures do, once a problem is identified, steps are taken to solve the issue. Dahon is no different.

Manufacturing flaws are not the same thing as design flaws. You understand this, right?

The Dahon problem being discussed is not an issue with quality control in a new bike model. It is an uncorrected error in the telescoping stem design spread over multiple models and multiple years which is a potential safety concern.

Besides: if we're discussing a safety issue in Dahons, why bring up other manufacturers except to dilute the discussion?

its a good thing we have such a deep knowledge base in design and engineering in here.....
sprinkle a few armchair lawyers into the mix ...

its a free world boys and girls , you can indeed invent something and go out and built it yourself ..... maybe even sell it and become successfull ....

in the meantime ... eat a little better breakfast and keep those quickreleases tight enough.
Versus looking to blame somebody else and call it design defekt ( which it aint, as many many hundredthousands of happy custiomers doesnt seem to have that problem )

Thor

Thor, does Dahon do anything wrong?

Because you seem to be taking the same approach with other people's safety issues as you took with mine: namely, to claim that anything that goes wrong with a Dahon is the fault of the rider.

It's striking how you defend them vigorously regardless of anything they could possibly do a little better. Is it just your own customers who ride them correctly, and the rest of us are idiots?

wil have to agree
 

I will have to agree with Thor,
If you pull against the handlebar like a mad man you feel some flexibility in the post but if you sit nicely on the saddle and pedal normally there is nothing noticeable.... I have been testing and riding my 2007 Mu p8 since last week and so far i am pleased... i treat the bike with respect like Thor mentioned.... nothing crazy and the bike serves me well. :innocent:

There are some sarcastic lions in the Folding Bikes den, Danno.

The torsional stresses placed on long-riser folding handlebars are a generic challenge that must be taken up by all manufacturers seeking a fold compact enough to let the bike be carried into the passenger area of a bus, trolley, train, or subway car. This is not a Dahon-only issue, in that sense; see also Brompton, Birdy, Giant, Mezzo, among others; these makers too have had to address the torsional and fatigue issues (I'm not saying that their bikes are failing in this respect, or even that Dahon's MTTF is briefer).

You don't have to be a lawyer to be an educated consumer; and you don't have to be an engineer to understand the basic principles of simple levers and metal fatigue.

The auto industry teaches us that safety concerns are consumer-driven. As more and more bikes become commuting bikes (rather than simply leisure-time rides or daredevil stunt machines), safety and durability will receive greater weightings in the cost-benefit analyses.

A cynic might think that marketing pressures/opportunities are causing beta-stage designs to be put into production. Is MTTF data available for these designs? I am trying to find out what special testing protocols, if any, have been established by ASTM for stem risers that fold and for bar-clamps that are meant to be unclamped whenever the bike is folded.

Regards
T

The discussion is not about flexibility in the post nor about pulling on the handlebar like a mad man. It's about the post rotating about the vertical axis after pretty mild riding (for me anyway).

Too much goalpost-moving here guys. This is a design defect in every Helios P8 I own and Mu P8s I've tested, and it's safety issue.

Weld ?
 

Why not just take it to a weld shop and get the post welded to your specific height.

As discussed, the specific height is incompatible with the folding attachment magnets.

You could make adjustments to the magnet i suppose.

Old problem that I still have on my speed 7-definitely an issue in design!
 

I have had my dahon years now regularly serviced and ridden sensibly and other than a new set of pedals tho only real issue I had was this one,in the end the screw sheared off & if not for cables they'd spin around infinitely! Dahon had to recall its jet-streams due to a faulty in the post but this bar problem remains it looks like,standard bars no mods,must fix! Did think about welding a pin in so i could still pivot up to fold! I'd like to keep it for now as a back up as my new bike comes soon & that's electric so will be a tank if the motor/battery dies,be easier to get this back out! Should I update the clamp altogether for the newer fatter ones? My bikes got to be 10-12 years old now,the post isn't the telescopic type either and I spin plenty too ;) Thanks all

Not a safety issue I saw which made me chuckle
 

this is definitely a safety issue as countless times since the little screw sheared off I've gone for my brakes and they ain't there!you gotta twist them up or down by which time you could've hit someone or something luckily it's not yet happened to me,touch wood never will!

op had the upper part of the adjustable handlepost spin ... ( despite the groove and the internal blop which should eliminate that. )
Now tim if I understand it correctly has the handlebar spinning in the top quick release ....
he bike in question is 14 to 17 years old I assume, they had a slot in the quick release and a pin welded to the steel handlebar. I have not seen any alloy bars slip in anything 10 plus years and younger


Quick releases are obviously not for everybody

Hi,

I encountered same problem, I had two Dahon bikes, one is aluminium frame, another is chromoly frame, the aluminium one got the problem while the chromoly does not.

I notice that the aluminium one is having thinner material in telescope parts and I think aluminium is softer , so that create the problem,

I followed Jose to add a music wire (a used guitar wire) to fix it, it seems ok, but not yet try on the road.

thanks to Jose ;-)

Eric

Hi Eric!

My Dahon is alive and well. I've since replaced the music wire with an addional clamp (I think its a seat clamp). This has worked much better than the music wires - which tended to slip out.

Sorted...sort of!
 

That's it,bars rotate & brakes are no longer in front of you...my bikes old & I managed to fix this by filing down the burs created where the pin had sheared off,a bolt cut & replaced that pin & needs a little off the top to slide right back but it's better,tho feels temporary & the bars are a lot wobblier nowadays,it's a tired old bike that's served me well,& still does for now...
thanks Thor

Hi Jose,

Thanks for yr advice !

some more background info:

My Chromoly model was bought in second hand, while Aluminium was bought in brandnew, both in 2+ years service, the mileage of Chromoly is about 10 times more than Aluminium, so I concluded that is a design issue...

I tested the music wire for 25km yesterday, it is working fine, since the height of handle stem is matched with the folding position, I do not need to adjust it often(I used to ride on lowest stem position). I may buy a additional quick clamp later on though. On the other hand, I had to adjust the Chromoly to the highest positon (beyond the red dot) to fold it due to the frame shape different between two bike.

Eric