Folding Bikes - Downtube Mini handlepost broke

I already post this in Downtube.com forum, and I'm not really want to say anything bad about the bike here. Just want to share the experience (although I'm not a regular poster here).

First, the picture.

http://img710.imageshack.us/img710/5148/dtmini.th.jpg (http://img710.imageshack.us/i/dtmini.jpg/)

It was wobbling for a while. I thought something loose, but couldn't find a way to tightening anything, so I thought it's nothing serious. Then, today, it's getting worse very fast, and finally broke when I was riding on the side of a fairly big road with a lot of cars beside me. When the post leave the bike's body, I was still at quite some speed and didn't lose my balance. At the time I was frighten and looking for a way to safely "fall". Luckily I did. What a day.

I already posted on DT forum, but I'll ask here too anyway. Does normal local bike shop have a spare part for this? It seem quite a specialized part for me. (I know next to nothing about bike though.) This is a first generation DT mini, so I'm not so sure Yan has parts for this either. It would be very sad if it can't be fixed.:(

Yikes! Thanks for the warning. I'd better go check mine out.

Sure glad you didn't get hurt. This could have been really damaging....

can't a dahon handlepost fix this problem? brakemeister alias thorusa has some answer?

slightly off topic: a week ago I flew over the cuckoo's nest oops, sorry...flew over my handlebar.
handlepost got bent. but it's a cheap steel bike, so I hope mine can just be fixed by welding.

What a strange design. A threaded fork with a quill adapter that threads into the folding handlepost riser. Looks like the threads between the quill adapter and the riser stripped out. Seems overly complicated and failure-prone.

Like Tedi said, Thor may have a Danon riser that would work. Gaerlan Custom Cycles shows a couple here:

http://gaerlan.com/dahon/stem.htm

It would be the DAHONSTAJ118 or DAHONSTAJ1 parts shown on Gaerlans site, depending on the size of your bikes steerer tube. Gaerlan says the first part is discontinued, but that just means HE doesn't have one. Someone else might.

A inexpensive option, depending how high you like your bars, would be a regular quill stem with a set of ape-hanger bars. Then carry an Allen wrench to loosen the bars and fold them out of the way. Or loosen the stem and pull it out of the steerer.

A final idea would be to part your bike out on ebay and in the meantime buy a new folder like a Dahon Curve. The Downtube Mini has been discontnued so there is a market for spare/used parts. Somewhere, somebody dearly wants a Mini frame or even that rear IGH wheel.

Good luck. Whatever you end up doing, please post a follow-up here.

I had an issue with my 2009 Mini handlepost - it was wobbly from day one and couldn't be tightened up; I had to shim it. I contacted Yan and he sent me a replacement - unfortunately he didn't have any 2009 handleposts, he sent a 2008 handlepost with some odd handlebar to go with it. He might still have some around, it's worth a call. At the time I also contacted Thor to see what Dahon parts might be compatible, and we couldn't work out if any would fit properly.

Good luck!

Thank you all for suggestion! I'm happy with my DT Mini (not when it broke, of course) but when I told this to my mom, she want me to go get a new one and if the Mini is fixed then give it to her instead. You know how much parents worry about you. (I'm far away from home too). So, I'm actually looking for a new bike and looking for the handelpost for my Mini.

I want one "step up" from my mini, but want to keep overall "functionality" the same. (Sorry but I don't know a better word for "functionality"). A quick research points me to Dahon Curve. I'm hooked to IGH so it's either D3 or 2008 SL. (No one find a place to buy 2010 XL yet right?) I'm going to check out my LBS today. Seem like they have some Dahon and Brompton in stock.

Do you have other suggestions? I like 16"+IGH of my Mini, so a bike that have both of these are highly prefered. Thanks in advanced!

Just back from my LBS. They don't have any Curve, but got some Brompton for a test. And damn, I love it. I park my bike on campus so I'm afraid of it being stolen, but I really like it :( Now what should I do?

How stupid I am? I just realized that Bike Friday's factory is in this very town I'm in. Tikit looks pretty nice too, but to get an IGH I have to pay at least $1650 :(

Have you looked at the Kent Compact Nexus 3:

http://ridethisbike.com/products/Kent/compact-Nexus-3-speed-folding-bike.htm

or what about the Giatex PNY:

http://ridethisbike.com/products/Giatex/PNY-SA3-folding-bike.htm

If you don't like either of these bikes, you might try contacting their manufacturers about the handleposts. Both bikes appear to use the 1.125 inch quill design like the DT Mini.

If you *live in Eugene*, I would think very carefully about *not* getting a Bike Friday. There's something to be said about the level of service and support you'd receive.

@JosephLMonti: Thanks for your suggestion! I probably won't get one of them, but it would be nice if I could get the part.

@feijai: Yes, I'm seriously thinking about getting a Bike Friday. There are two things that I'm worry about.

1. Theft. With DT Mini, I can park it anywhere and don't have to worry too much. But with BF I might not be able to do so.
2. I don't wanna pay $1650 for Season Tikit, but I do want IGH. I think I'll give them a call (or a visit, even) to see if they can put any IGH in T-Model so it (hopefully) could be cheaper than that.

How long have you had your Mini when the handlepost broke and what kind of riding did you do?

I've had my Mini for 3 months and can feel the handlepost flex occasionally when I pedal hard on grass or going up a hill. I try to watch how hard I pull back on the bar in these situations. Most of my riding is on flat pavement.

I have got the exact problem on one of my very old folding bike. What I did was to take that part to a local auto mechanic who work on mufflers and have him weld it back for me. So you might want to do the same thing and it should be very cheap to repair. :)

@JosephLMonti: Thanks for your suggestion! I probably won't get one of them, but it would be nice if I could get the part.

Come to think of it, you might also try Citizen Bike (just for the handlepost):

http://www.citizenbike.com/catalog.asp?product_category_id=1&product_id=10

Looks like their Tokyo model's handlepost might work as well.

Have you contacted Downtube? They do carry spares. If you're out of luck, I actually have a spare one that I could send you. It is the later model which uses a ahead stem for some forward reach.

@jur: I did post at their website, but no respond. I may have to make a call. I'll let you know if I can't get a part.

Also called Bike Friday today. They said there is no cheaper option for IGH tikit. :(

@Hypernova - I would definitely call or email Yan. While he does post on the Downtube bulletin board sometimes, I don't think he checks it every week. I'm sure he'll be able to work something out with you.

How long have you had your Mini when the handlepost broke and what kind of riding did you do?

I've had my Mini for 3 months and can feel the handlepost flex occasionally when I pedal hard on grass or going up a hill. I try to watch how hard I pull back on the bar in these situations. Most of my riding is on flat pavement.

About two years. I do a 5 minutes ride from apartment to school daily. A little bit further to shopper once a week, and do ride longer once in a while. My route have a few bumps, but nothing big.

I would recommend you to keep you eyes on it. Mine was suddenly get worse and broke off. It is versy dangerous

Hey, just wondering if you've heard anything?

I had no idea the Mini was discontinued! I checked the Downtube site and there's nothing there about it. I searched the forum for news of it, but couldn't find any mention--did I miss a thread? Too bad, must not have had market enough. I'll miss the Min.

from all my past research on folding bikes, downtube and citizen use the same folding stem, which use a standard headset. They can be replaced with a standard nonfolding setup, or you can actually find these generic folding stems on ebay. They're used on a lot of the chinese offbrand folding bikes.

Hey, just wondering if you've heard anything?

I had no idea the Mini was discontinued! I checked the Downtube site and there's nothing there about it. I searched the forum for news of it, but couldn't find any mention--did I miss a thread? Too bad, must not have had market enough. I'll miss the Min.

Here's the Downtube Bulletin thread discussing the Mini:

http://www.downtube.com/Folding_Bike_Forum/read.php?2,796

from all my past research on folding bikes, downtube and citizen use the same folding stem, which use a standard headset. They can be replaced with a standard nonfolding setup, or you can actually find these generic folding stems on ebay. They're used on a lot of the chinese offbrand folding bikes.

Interesting - do you have any links to where I can buy a Citizen folding stem, or the generic folding stem? The stems I see on eBay, like this one (http://cgi.ebay.com/New-Alu-Folding-Bike-Stem-Handlebar-adjustable-Bicycle_W0QQitemZ180468445666QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2a04c1f1e2), do not look like they would fit my Mini, but it's hard to tell from the photo.

Unfortunately thats the only one I see out there too at the moment.

I was desperately looking everywhere for a replacement folding stem for my classic dahon this past fall and had seen several of the generic ones out there on ebay. I think they were going for around $35. I have a Downtube 9fs, and have seen several Citizen bikes up close and compared the folding stems.

btw, I just looked at my 9FS again and it has a threaded headset. The one on ebay currently looks like its made for threadless headsets.

The handlepost that's currently on eBay looks like it might fit the Downtube Nova but not any of the other models. I think the best starting point would be to call Citizen Bikes and ask if they would either sell you a spare handlepost or at least direct you to their supplier.

I had apparently EXACTLY the same thing happen to my Mini stem. Complete with shorts-staining traffic incident. You can see pics of before and after I had it welded here under the Dahon handlepost recall thread:

http://www.downtube.com/Folding_Bike_Forum/read.php?3,699

GOOD LUCK finding a replacement stem. The only one I found was at a Dahon dealer in England who, when I told him it was for a Downtube, told me to go suck eggs. Yan told me I was SOL, just get it welded.

I tried to buy the older style Dahon 1 1/8" stem from Thor a couple of years ago to fit the vertically adjustable handlepost but he sent me the wrong thing and I never follwed up. Boy do I regret that.

I considered buying a lot of these from China, very cheap of course, but the smallest shippable quantity was 50.

My weld is holding BUT I still have wobble, about 1cm. Apparently it comes from the design whereby the actual quill wedge is inserted into the bottom of the handlepost and held in place by two set screws. Probably so that 1" or 1 1/8" quills could be interchanged for manufacturing versitilty. It seems the play from the steel quill wearing on the aluminum ahndlepost is causing wear, and I theorize the motion induced is transmitted to the hinge weld and destroys it. I'm considering driving a couple of finishing nails into the small space between the top of the quill and the handlepost to shim it.

I'm also considering trying to fit the new, weird Dahon stem to my steerer tube...maybe by threading the inside of it? Or maybe welding the Dahon contraption to an Ahead stem riser with a 1 1/8" quill. Any thoughts on this anyone?

Or maybe I'll come to my senses and throw the damn Mini in the dumpster while I'm still alive.

Please let me know how things work out for you, especially if you find a source for a 1 1/8" folding stem.

An easy solution would be to get a quill-to-aheadstem adapter and fit a modern handlepost such as a Dahon or one of those posted earlier.

I have been having a bizarre problem on my Mini handlepost so I thought this an appropriate place to mention it.

The QR that keeps the post upright sometimes fails. That is, suddenly, while riding, it slips into folded position, making steering problematic. When this happens, as long as I keep the handlebars upright (i.e. I press forward on them a little) I can keep control of the bike to get out of traffic and retighten the QR. And every time this has happened, the QR had not come undone; it had somehow pivoted so the handlepost got loose.

What exactly is happening? I don't know! Nothing is broken (including, so far, my teeth). Still, I worry....

Obviously my chief suspect is user error; but since this has happened a half dozen times over the last year, and with increasing frequency, I've become increasingly cautious. Now I always make sure I have tightened the QR correctly; and even so this happens with increasing frequency (and completely without warning).

Has something like this happened to anyone else?

Perhaps the QR sliding surfaces are worn? With lower cost QRs, the plastic may wear through and them you have lost the resilient block that is an important part. The movements from riding the bike and pulling on the bars can easily work it loose if there is no 'give'.

Also, maybe some mild Loctite in the thread to prevent it from turning?

Perhaps the QR sliding surfaces are worn? With lower cost QRs, the plastic may wear through and them you have lost the resilient block that is an important part. The movements from riding the bike and pulling on the bars can easily work it loose if there is no 'give'.

Also, maybe some mild Loctite in the thread to prevent it from turning?

1. The QR's sliding surfaces do appear to be worn, which is puzzling; how could they be worn? I'm thinking I may be able to fix the problem with a flat file; if the parts don't mate perfectly there will be movement that may be causing the problem. But removing metal seems a bit drastic....

2. Yes, good suggestion, I'll have a look at that resiliant block; I'm pretty sure it is not missing, but it may have lost some of its resiliance over the last 33 months and 7000 miles.

3. No, Loctite is not the answer; the QR adjusting nut is not turning.

Above all, though: I'm wondering if anyone else has noticed this!

2. Yes, good suggestion, I'll have a look at that resiliant block; I'm pretty sure it is not missing...Actually I meant worn through or at least very thin, not missing as in fallen out. Ie missing a thick amount of plastic; so, not much resilience left.

Wearing would be inevitable - dust and grit would settle and with each operation, erode some material. I think a new QR or at least a new piece of plastic would be worth investigating.

Are you lubing the sliding surfaces from time to time?