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Folding Bikes Discuss the unique features and issues of folding bikes. Also a great place to learn what folding bike will work best for your needs.

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Old 08-21-08, 04:35 PM   #1
locke_fc
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Mu P8 handlebar problems - not happy

Hi everyone, this is my first post ever in the forum, and it's the exact same one I posted earlier today on the Dahon forums. Maybe some of you guys might be able to advice:

I bought a 2008 Mu P8 two weeks ago and was very happy with it until this evening. True, I had to have the gears adjusted at my LBS a few days ago, since they weren't shifting properly. But the guy at the shop warned me when I bought it that the gears may need a minor adjustment, so no problem with that.

However, this evening while riding out I suddenly noticed that the handlebar was clearly not perpendicular to the front wheel, so I thought "never mind, I'll tighten whatever needs tightening when I get home". So I get home, pick up the user manual and I read tigthen this, tigthen that and loosen that.

And I get to Step 3.5 and read "...LOCTITE..."

What??????

You cannot be serious. Am I supposed to believe that it is perfectly normal for a critical part such as the handlepost, in a 700 (yes, that's what it costs over here in Spain, in Euros) bike, to require adjusting with GLUE after less than 25 hours' use on streets and some flat paths in the park???


Surely, this kind of, erm, adjustment is not intended to be made on a bike that's been used as recommended for so few hours. Right?

Am I right to believe that my bike, or at least this handlepost is faulty and I should seek a replacement from the dealer who sold it to me? Cause I'm no engineer nor mechanically inclined, but in my book, applying glue is not something I expect to do on a 700 piece of equipment, labeled "P" as in "Premium" after a mere two weeks' use.

NOT HAPPY at all. What would you guys suggest I do?
Thanks in advance for your help and advice.
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Old 08-21-08, 04:46 PM   #2
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In my layman's opinion, the stresses that occur with these long riser handlebars with their greatly increased mechanical "advantage" (ironic term in this context) really "push the envelope", so to speak; the metal threads, subjected to such forces, need a little "boost" from the thread lock compounds. This is something inherent in the small-wheeled design: the headtube is close to the wheel, the handlebars are far from the headtube. Compare the shorter length of the stem riser (steerer tube) on 24" wheels, e.g. the Airnimal.
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T

P.S. One could address the issue with coarser threads and heavier gauge, but this runs counter to the lightest-weight-possible design goal that governs bike design.

Last edited by timo888; 08-21-08 at 04:54 PM.
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Old 08-21-08, 05:17 PM   #3
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Loctite which component? I think the manual only suggests to loctite a nut on the handlepost latch and frame hinge/clamp.
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Old 08-21-08, 05:35 PM   #4
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That's right, it's the clamp screw on the handlepost. But my biggest doubt is: isn't the fact that this has happened so soon an indication that this part may be faulty? Do I have technical grounds yo ask my LBS for a replacement rather than a repair?
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Old 08-21-08, 05:45 PM   #5
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The terminology gets confusing. I can only find a reference to loc-tite in my manual in the section on 'adjusting the steel handle post latches'.
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Old 08-21-08, 05:46 PM   #6
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And 'adjusting the frame latch'. This has nothing to do with your problem.
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Old 08-21-08, 05:51 PM   #7
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Quote:
Originally Posted by locke_fc View Post
That's right, it's the clamp screw on the handlepost. But my biggest doubt is: isn't the fact that this has happened so soon an indication that this part may be faulty? Do I have technical grounds yo ask my LBS for a replacement rather than a repair?
See my reply in the Dahon forum.
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Old 08-21-08, 06:06 PM   #8
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The tension in the handlepost latch needs adjusting every so often so that there's no play. The loc-tite suggestion is just a means of avoiding having to adjust so often. Gradually with friction the handlepost latch surfaces will wear a little and some adjustment would have to be made to maintain tension, loc-tite or not. The (separate) issue with the handlepost rotating is just to do with the q/r clamp pressure. I don't have a problem with that on my VItesse (had plenty of other problems). The Dahon hype does rather suggest these are the most imaculately engineered bikes EVER, and they're not, but I don't think you've anything to worry about.
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Old 08-21-08, 08:31 PM   #9
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It's not just about friction. I never adjust my Mu's handlepost height, but the QR nut still needs tightening every 2 weeks or so. Likewise the QR at the top of the handlepost.
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Old 08-21-08, 08:36 PM   #10
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In fact, I'm considering swapping my adjustable Mu handlepost for a non-adjustable one that folds to the outside, like on the Speed TR/Speed Pro.

Does anyone know how much weight this is going to take off? How high (headtube to bar) is the non-adjustable post?
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Old 08-21-08, 10:21 PM   #11
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This appears to be the identical problem that was discussed in this thread.

Last edited by feijai; 08-21-08 at 10:25 PM.
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Old 08-22-08, 02:56 AM   #12
locke_fc
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Quote:
Originally Posted by feijai View Post
This appears to be the identical problem that was discussed in this thread.
Yes it was the same problem, actually, as thor and others told me over at the Dahon forums. It's sorted now. I was somehow misguided by what I read in the manual and thought it had to do with the handlepost headset. Still, I'm beginning to think that folding bikes require more maintenance and regular minor adjustments than I thought. Or maybe it's just Dahon ones, I don't know.

Quote:
Originally Posted by chagzuki View Post
The terminology gets confusing. I can only find a reference to loc-tite in my manual in the section on 'adjusting the steel handle post latches'.
It's on page 42 of the manual (page number may be different in yours, as my manual has the Spanish version first). The section is called "Headset adjustment instructions", and it is specifically mentioned as a solution for the handlebar not being perpendicular to the front wheel, which was my exact problem. That's why I got confused.

Thanks everyone for your input and advice.

Last edited by locke_fc; 08-22-08 at 03:03 AM.
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Old 08-22-08, 08:59 AM   #13
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heheh

Sure apreciated that you come back to us and tell us that the problem is solved ....

a lot of folks have a problem , they post it and than they dissapear... just to leave us ole fellows typing for weeks to solve their problem , while they are happily riding their bikes and have forgotten about their post long ago.... lol

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Old 08-22-08, 09:35 AM   #14
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Quote:
Originally Posted by locke_fc View Post
Still, I'm beginning to think that folding bikes require more maintenance and regular minor adjustments than I thought. Or maybe it's just Dahon ones, I don't know.
Definitely folding bikes will take a bit more adjustment/maintenance than a rigid full size bike because you are adding several mechanical elements that allow the bike to fold. Some are going to be better in this respect and some worse.

I think you also need to consider that any new bike needs a bit of adjustment as you ride it and things loosen/settle in. Your cables will need adjustment to keep the shifting/braking optimal as you've already discovered and other parts of the bike may need service as well. This is why most bike shops offer a free tune up with a new bike after a few weeks or months depending how much you ride the bike.

My experience has been once you get through this initial phase your bike should not require frequent attention. If it does something is wrong or you've got a poorly designed/constructed bike.
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Old 08-22-08, 09:44 AM   #15
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Originally Posted by joseff View Post
In fact, I'm considering swapping my adjustable Mu handlepost for a non-adjustable one that folds to the outside, like on the Speed TR/Speed Pro.

Does anyone know how much weight this is going to take off? How high (headtube to bar) is the non-adjustable post?
I did this with my 2006 Helios P8 as I was getting rather disconcerted by the movement in the handlepost. It took ages to track down the part and at one point Dahon UK told me it would not fit my bike. Well I got the part and it fitted perfectly. There's no more rotating, the bike is lighter, it folds quicker and rides better. The fold is slightly bigger, but it is a worthwhile upgrade.
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Old 08-22-08, 12:36 PM   #16
locke_fc
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Quote:
Originally Posted by vik View Post
Definitely folding bikes will take a bit more adjustment/maintenance than a rigid full size bike because you are adding several mechanical elements that allow the bike to fold. Some are going to be better in this respect and some worse.

I think you also need to consider that any new bike needs a bit of adjustment as you ride it and things loosen/settle in. Your cables will need adjustment to keep the shifting/braking optimal as you've already discovered and other parts of the bike may need service as well. This is why most bike shops offer a free tune up with a new bike after a few weeks or months depending how much you ride the bike.

My experience has been once you get through this initial phase your bike should not require frequent attention. If it does something is wrong or you've got a poorly designed/constructed bike.
Yes, that's what I'm hoping. Also, when I bought the bike, the shop told me to bring it back in 6-8 weeks for a tune up.

The thing with folding bikes is that perfectionist (or should I say obssesive ) types like me won't stop wondering whether this screw is a bit loose or that clamp not tight enough. Hopefully I'll get to know the bike better and how to make most adjustments myself.
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Old 08-22-08, 03:31 PM   #17
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The thing with folding bikes is that perfectionist (or should I say obssesive ) types like me won't stop wondering whether this screw is a bit loose or that clamp not tight enough. Hopefully I'll get to know the bike better and how to make most adjustments myself.[/quote]

I know EXACTLY what you are saying, same thing here buddy.... i just came back from ride and i was thinking to myself... i hope everything is ok with the bike... it has been almost a week since the last time i have checked ..... well, basically when i ride i do hear some clicks and other noises from the bike although everything should be fine and the bike is fairly new as well. I guess we all have to accept that folders are folders and there will be some clicking noises and other "riding noises" from the seatpost nor handlepost etc....
People for some reason like to complain about Dahon - compare to other brands i think you get the best bang for the buck if you find the right deal.

So, yes maybe Dahon has problems and issues to address but at least i feel that i bought a product from a well known company and when you have someone like Thor around here he will jump to the pump when you need help !!!!

Last edited by Tommy C; 08-22-08 at 03:35 PM.
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Old 08-23-08, 05:17 AM   #18
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"It is commonly believed that bolts and nuts often come loose for no apparent reason. However, the common cause for threaded fasteners loosening is simply lack of tension during initial assembly. Vibration, stress, use, or abuse cannot typically overcome the amount of clamping force in a properly sized and secured threaded fastener. As a simple rule of thumb, any fastener should be tightened as tight as possible without failure of the thread or the component parts. This means the weakest part of the joint determines the limits of tension, and hence, torque."

http://www.parktool.com/repair/readhowto.asp?id=88
[emphases mine]

Regards
T
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Old 08-25-08, 08:44 AM   #19
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The handlepost latch is loosening rather quickly on my Vitesse and it's getting on my tits. Which type of Loctite should I go for, medium or high strength (never used the stuff)? It'll have to be applied around the nut, so I'd imagine it'd have to be the high strength?
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Old 08-25-08, 09:25 AM   #20
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I went with medium on the quick release latches on my bike. Worked fine. If you never, ever want to adjust it again during the lifetime of the bike, go with high strength. It requires heating to loosen.

--sam
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