The mystery was the handle bar stem folding hinge/clamp. It looked the same as any other Dahon, except that when you undid the quick release lever, it refused to open, staying quite firm. I couldn't determine the cause without opening it - catch 22. Memory says there is a spring inside to help it the "latch" open, I assume the spring has broken, so the latch doesn't open. The latch I could see could be prodded to move a bit, but nothing more.
I pointed the owner to a LBS that does a lot of folders, so they could order any bits needed (probably a complete new stem).
NB. Undoing the side clamp bolts doesn't help - there is a quill stem type bolt only accessible once the folding hinge is open.
Anyone else come across such an occurence?
This bike had a tight cable running from just behind the headset to the left side of the BB shell. Never seen this on a Dahon before.
The fact the cable under tension is trying to open the frame folding hinge struck me as a tad odd at first. But then I thought perhaps in makes some sense, allowing for the American tendency to sue for something caused by careless owners, or even manufacturers.
By my observation, the Dahon clamp is a poor design, a lot of owners don't realise it needs periodic adjustment to keep the cam mechanism clamping the frame tight. About half the Dahons I see are being ridden with the clamp not tight enough (even though the cam lever is pushed fully in), the 2 halves of the frame move a bit relative to each other. Eventually the interfaces wear so much the clamp can never be adjused tight again.
My hunch is the tight cable, while trying to open the join, keeps the clamp under tension - if a bit not fully closed - which probably is safer (or less dangerous) than using it loose.
