bentstrider83

This is a circa 2008 Dahon Speed D7. Bought it from a CG list ad back in 2020 for about $180. Threw a Bafang electric unit onto it and it's been my daily ride ever since. I fold/unfold it quite regularly since it's in my semi tractor. I'm on the heavier side and also ride with my cat on my back and usually fully loaded rack bags.


Over the past month, the folding out has become gradually harder to do than folding it up for storage. I then noticed this odd bend with the pivot point in the posted pic. Again this is my everyday ride and I just want to see if it's safe to continue using. Or should I look into something rated for heavier loads like a "Zizzo"?

Ogsarg

Guessing the hinge pin is bent. I don't suspect the pin could break but it may eventually become impossible to fold.

I see a hole on the bottom where you may be able to remove the pin and replace it. If so, that may get you some more miles but my guess is it's exposed to more weight than it was designed for and would happen again.

bentstrider83

I was looking at the bottom closely and notice there's also an Allen screw that could be removed. I'm guessing this will be a bit of a job and can be done with the proper tools(possibly drill it out if needed). I'm still going to ride it in the meantime. But I'm also hunting around for both aftermarket replacement bolts/pins and may also contact Dahon for some replacements. Hopefully they don't ram the whole "get a whole new bike" thing down my gullet.

2_i 

The more you bend it, the harder it will be to fix. I would take care of this as soon as possible.

bentstrider83

"Soon" is wishful thinking. I'm digging as far as Google will let me and the pins and other folding latch components are difficult to find out there short of dealing with international sources. I'm going to hit up Dahon and see if they provide any sort of parts kits(didn't see any for open sale on their website. All they have are cosmetic accessories as opposed to actual hardware).

CrimsonEclipse

OOF
My guess is that the pin is worn.
The fact that it's difficult to fold is not a great sign and increasing wear significantly to the pin and possibly the frame.
This is a folder with a significant aftermarket motor, with considerable loads on it, frequent use, and multiple loads that it was not designed for.

If you are able to remove the set screw ad tap out the pin, you might have an idea if only the pin is worn or if there is frame damage too.
In short, if there is frame damage (which is likely), then you need a new frame.

You might want to consider a purpose built electric folding bike.
The initial financial hit hurts, but it is significantly less expensive than a frame failure and broken bones.

bentstrider83

All points considered. Of course if the broken bones don't get me to the hospital, a stress induced heart condition from worrying about money and not enough work probably will, lol!!


That said, I probably will look into the $1000 options that exist out there. The motors are neutered of course. But I don't see myself going up against any triathletes any time soon.


On that note as well, I'll have to look into metal recycling places or donor frame to some coop. I just don't like to throw things away.

tds101 

Too bad you don't live on the East Coast. I have a Dahon Speed P8 I could have hooked you up with. All I'd need is for someone to pick it up.

bentstrider83

Of course by the time I have the resources squared away for that mission, it'll probably be long gone.

tds101 

It's not going anywhere. I just have it gathering dust in my basement. It needs a derailleur, so it's not perfect. But for a "gimme" it's fine. I'm just giving it away. LoL!

CrimsonEclipse

tds101 offer sounds like a good one.
What's shipping cost for the whole bike or just the frame?

Guaranteed cheaper than a new frame.
(It'll be a day job swapping out the frame, but still)

bentstrider83

I'll keep it in mind. That is if I'm still not swayed to go to something purpose built like a "Lectric". Of course one thing I hate about these purpose built folding ebikes is that they all nearly adopted the fat tire fad.

CrimsonEclipse

I agree with you there.
Most of the fat tire folders have knobbies and they sound like a 4x4 coming down the road and the knobbies sap speed/distance/turning capability

Tho the Letric XP has a 20x2.4 which you can get a pretty good slick on it.

bentstrider83

Might look into that one as well moving all my Bafang components and that $300 rear wheel I got for it over to a 300lb rated Zizzo. Of course while the Zizzo retains much of the Dahon physical appearance, the offerings of Lectric are only $500 more.

Of course I got to hold off until I get tires replaced on my pickup truck as well. Or do I??

bentstrider83

Got an email back from Dahon and they put it bluntly that "they do not sell the pin components" and "the frame needs to be replaced". Not to get too ranty on here, but way too many people seem to be putting liability and injuries at the front of things as opposed to "do it yourself".

Definitely born in the wrong era.

tds101 

No shipping available, pickup only I'm afraid.

CrimsonEclipse

ah poo....

sorry strider

bentstrider83

That's alright. I'm just going to pull the trigger on the Zizzo Forte and roll with that once funds are accumulated. Until then, I'm strapping the ginormous Catrike Expedition to the back of the semi!! Of course I'll have to get a tarp small enough to bungee cord around it. Best solution for now to fill the ride gap!!

50PlusCycling

The upper and lower parts of the hinge look okay. The center looks worn, it may be the pin or it may be the hinge. The pin is easy enough, you can find a bolt at a good hardware store, just bring the old one with you. If there is a bushing, that can be harder to replace (I just put one in my old Moulton Stowaway), but a bushing would protect/reinforce the hinge. If you have a friend at a machine shop (these are great friends to have), he could sort out your bike in an hour or two.

bentstrider83

Sounds like a project to tackle if these loads I'm running keep getting spaced out. Definitely a lot better than having to deal with the headache of carrying my trike on the back of the semi. Until funds become good again, this'll definitely be one way to try and save the Dahon.

bentstrider83

Since I bit the bullet and ordered a new Origami Bull, would it be wise to have the frame welded permanently unfolded with the Dahon? I don't really want to trash it and it could be a nice, small caliber, spare bike to keep around.

Pinigis 

You can probably get a machine shop to bore out the hinge and sleeve it for a new pin. I really don't think that your pin is bent, it looks more like the hinge is just warn out.

bentstrider83

In that case I'll just put it in my storage for now. Make some calls and get some takers for the job.

Duragrouch

OK, as they say, Danger Will Robinson! (showing my age).

I have a Speed frame, but never pulled the pin yet. Yes, at minimum, the pin is bent or the holes it fits in are enlarged. But given the close clearance of the hinge parts, the pin could be completely sheared-thru, in which case the bending loads at the upper part of the pin are greatly increased, and you are riding on very borrowed time.

Before I get into solutions, the offer of a replacement bike from tds101 is extremely generous, grab it if you can. If it has a conventional derailleur hanger (probably, being a P8), a replacement is easy. If it has a Dahon compact derailleur (junk, IMO, and *expensive*), you can fit a conventional derailleur, shimano makes one for 6/7 speeds with a "claw-mount", you can mount it under the axle nut (or quick release), and it may work for 8 speed as well. Typically $15. Mine is a mid-length cage (GS?), more capacity than a short cage, but still sufficient ground clearance, versus a long-cage. I think the new 20" Dahons all come with this length cage. There's a protrusion on the inboard side of the claw, intended to fit in long slotted dropouts, which the speed doesn't have. Simply take a dremmel tool and grind the protrusion off flush. Bonus points: Not only will it work with original grip shifters, it reverses the shift direction to "conventional" (from reversed "Rapid-Rise" with the compact derailleur), vast improvement, and better shifting, just the shift numbers on the shifter are wrong. Oh, the chain needs to be longer than with a compact derailleur, you'll need a new one.

Frame fix: Obviously, #1 is removing the pin and replacing with a new one. After that, one of two things will greatly improve frame strength, and reduce bending loads on the hinge.

#1:
https://dahon.com/dahon-why-add-on-d...g-enthusiasts/

Newer Dahons have "Deltech", this is a diagonal cable that runs from just behind the head tube to the bottom bracket, triangulating the frame like a Bike Friday Diamond Llama, but still foldable because the cable is flexible. Now, they are advertising an "add-on" version. I just inquired with Dahon, that's supposed to be available in the USA summer 2024, no price provided yet.

#2: "We don't need no stinking Deltech": Obtain a piece of kevlar braided line (strong as steel, very low stretch), 1/8" diameter by about 6' long (5' should be enough, but just in case). (UHMWPE (Ultra High Molecular Weight Poly Ethylene, aka AmSteel, Dyneema, et al) might also work, just as strong, not sure about the stiffness. Other synthetics like nylon or dacron are out, way too much stretch.) You'll find these lines at a boat shop that has sailboat parts. Make a loop of that line, to wrap around the head tube at the bottom, rearward to the bottom bracket on the left side, around, then back forward to join the other end, so you have 2 strands of line running fore/aft, 2X the stiffness (you'll actually put the knot midpoint between the head tube and bottom bracket). You're gonna use a double-8 knot, as kevlar is slippery. You will fold the frame slightly to make that run a bit shorter, tension the line and tie the knot (not hard-tight, you want to check length, you'll need to adjust such that the line will be TIGHT when the frame is unfolded; On my bike, it is just tight enough so that I need to lay the bike flat and push gently with my foot to fully unfold.) If this will make your bike too difficult to fold and unfold, it's out. But this will make the frame a lot stronger. To tighten at a later date, will be super hard to undo the knot, so instead, put a spacer, like a piece of leather, under the line at one of the bends. Or, put some sort of paddle, mid-point on the lines, to twist them, like tensioning an old bow saw. You could also just use a loop of line at the head tube and bottom tube, and go to a boat shop that makes sailboat rigging, and have them make a cable with swaged ends, one end threaded, just like the factory Deltech, to adjust on the unfolded bike, attaching to the small kevlar loops at each end. I did the above to my Speed this past year, great difference, I haven't had to adjust the folding mechanism once since, whereas before, it was more frequent adjusting due to wear.

EDIT: I only had a piece of kevlar line long enough for the knot as shown below. With a longer piece of line, you could make a loop on one end (using a double-8 knot), then put a single or double trucker-hitch on the other end, in order to tension up the line, securing with half hitches, which you can do if the tension at the ending knot is 1/2 or 1/4 the tension in the rest of the line, due to the trucker hitch. That will be a lot easier to adjust orginally, and as time goes on.

EDIT #2: That added line as shown, WILL increase the strength of the frame, in vertical loading such as from rider and payload weight, because it will load that line in TENSION. It will NOT increase strength to resist forward (acceleration loading) from drive force thrust at the rear tire contact point (ground), as that would load the line in COMPRESSION, and "you can't push on a rope". I don't know if your drive motor was exerting exessive drive loads, versus human power.

Pic from my bike, before securing line ends with half hitches:


A friend says it's good theft-deterrence, appearing that my bike is held together with spit and baling wire.

Lest you think that line is not stiff or strong enough, those two strands of 1/8" kevlar will lift a good sized car.

tds101 

If someone is interested in a Dahon Speed P8 let me know. It's available for pickup, and It's a free ride. Let me know... Long Island, NY.