2bridges1bike

Hey Everyone

I recently came into possession of a 2007 Dahon Mu SL, how can I inspect the frame and handle post joints to make sure its still in good shape? Do these things have an unofficial "expiration date" after which they should they shouldn't be used anymore?

The bike is in decent shape, but does have some miles on it. I plan on using it as a commuter in NYC (7 to 10 miles each way) and will likely be taking it on bumpy terrain with potholes. Having a frame break of handlepost snap off in NYC traffic would not be good. Also, it looks like the year after my bike was made (2008) there was a recall (its on the CPSC website, I can't post the URL because I am new).



Thanks!

BromptonINrio

if you inspect the bike and its in good shape, ie no play on hinges or whatssoever you should have no problem.

1nterceptor

If you're in New York City; maybe bring it to BFold for a safety check/tune-up.
They're familiar with Dahon models; have plenty of parts and accessories(fenders/bags/water bottle holder/etc.).

fietsbob

Overhaul, clean and re grease..

2bridges1bike

Great suggestion, I guess shelling out some cash for tune up will be worth the peace of mind. I called b fold and they no longer sell dahon, they did refer me to another shop that still sells and services them.

linberl

I have the single speed version. Those frames are pretty bullet proof overbuilt. A good visual inspection, plus pinging it in different places to see if you hear sound changes, should be adequate. You can probably find the manual online (here is the ss version: https://dahon.com/wp-content/uploads...structions.pdf) which will give you some idea how to inspect the hinges, etc.

joey buzzard

Unless it`s been very seriously crashed it should be good to go. Do your due dilligence and check the frame out especially at the hinge, but in all likelihood it should be perfectly fine. Test ride it if you can too.

3speedslow

2007 is not old. The year built has nothing to do with the riding condition of a folder. You should be good if it passes your inspection checklist.

sweeks

I have a 2006 Dahon Mu XL (bought in 2006), and have had some issues that may give you some guidance. Bear in mind that I weigh about 210 pounds with a backpack, and ride over some fairly rough streets in Chicago. Since 2013 this bike has been my designated "winter" bike. The mileage is upwards of 12,500 miles.

Early in the ownership of this bike, I noticed small cracks radiating from the bottom of the slot on the seat tube. The round hole at the bottom, which serves as a stress breaker, was too small in diameter (IMO). By the time the bike had about 6 or 7 thousand miles on it, the cracks finally circumnavigated the seat tube and the little stub above the main frame tube, including the seatpost clamp, was disconnected from the frame. However, with the rider's weight on the saddle, the seatpost would stay in place (if a little loose) vertically; it also wouldn't rotate because the broken surface was irregular. The only down-side was that I could no longer lift the bike by the saddle. I fixed this problem by creating a couple short stays that connect the seatpost clamp to the frame's rack braze-ons. See the image of the bike and zoom in... the separated top of the seat tube is clearly seen. Basically this is an esthetic issue, as the crack has not propagated to any other areas. If I were to see these cracks today, in their early stages, I would enlarge the hole at the bottom of the slot to increase the radius of curvature.

This leads to the next issue. The stress-breakers on the handlepost were also too small (IMO) and cracks began to radiate out from them. I drilled stress-breaker holes at the end of these cracks in 2016 and they have not progressed. Image is attached.

A few years ago I noticed what appeared to be a crack starting to form across the top of the joint between the frame tube and the head tube. When it was about an inch long, and clearly progressing. I had the area TIG welded, and it's been fine since.

Another issue not having to do with the frame, but probably my weight, was the ThudBuster seatpost suspension, which fractured off the top of the seatpost about a mile from my train station in January of 2016. I had to ride the last mile standing. Luckily, I felt the saddle with a little more "suspension" than usual and stopped just as it came off.

So... if you're lighter than me, and you don't see any of the incipient cracks I've described, all is well. If you *do* have little cracks, consider creating improved stress breakers.



Mu XL in "Winter" form. See seat tube disconnect and stays.


"Crack-stop" relief holes on Mu XL handlepost. Stable for 3 years.


Taken on the train after riding a mile standing up!

grayrest

I was in BFold getting a hinge replacement this past weekend and was picking David's brain about my SatRDay when a customer called in from a garage sale asking about fixing up an old Dahon. From the eavesdropped conversation it sounded like the main reason he didn't want to work on it is that Dahon doesn't supply replacement parts past 6-7 years after sale so sourcing the parts is difficult.

sweeks

A good source of parts for Dahon bikes is ThorUSA-dot-com.

2bridges1bike

[Early in the ownership of this bike, I noticed small cracks radiating from the

Taken on the train after riding a mile standing up![/QUOTE]

Thanks for this reply, my bike has no where near this level of wear and tear. I gave it a once over for cracks and it seems ok.

I am also close to 200 lbs so I was a concerned about my weight as well!

BromptonINrio

Thanks for this reply, my bike has no where near this level of wear and tear. I gave it a once over for cracks and it seems ok.

I am also close to 200 lbs so I was a concerned about my weight as well![/QUOTE]

i wouldnt ride folding bikes with 200lbs wheight.
you need a diamond frame and folding bikes is a non go

BromptonINrio

christ!

you seriouly playing with your life and health.
this bike is way over redemption.
i just hope you didnt get hurt

Dynocoaster 

Just picked up this flyby, pretty much a Dahon MU with an 8 speed hub. I have a couple of MUs and they have been great.

linberl

Thanks for this reply, my bike has no where near this level of wear and tear. I gave it a once over for cracks and it seems ok.

I am also close to 200 lbs so I was a concerned about my weight as well![/QUOTE]

Keep a close eye on it and inspect it after every ride. In truth, you would be better off with something like a Bike Friday steel diamond frame, but as long as you check regularly for issues with the Mu (and hopefully riding will help you drop down a little, too) you should be okay. I wouldn't all panniers or any loads to your ride, though.

sweeks

Not all cracks are equally risky. The seatpost was the only one that *could* have been an unpleasant surprise. Thanks for your concern!

sweeks

Over 20,000 miles on folding bikes without any sudden or otherwise serious frame issues say otherwise.

tds101 

Please tell me you plan to do a restoration of this BSO,...because right now it's giving me friggin' nightmares!!!

Dynocoaster 

Yes , already threw away the bmx handlebars. I need to get a new stem. This stem had a recall on it in 2008.

tds101 

Thank you,...I can return to sanity once again,...