I've had a Dahon Vitesse D7HG for about 5 years. The main fold has been getting progressively (for want of a better word) "sloppier"... And of late I've been getting some alarming play in the frame, and even (twice) a frame that sprang open mid ride. I'd tried adjusting it the hinge, but nothing seemed to help - I just couldn't find a sweet spot that would close snugly as when the bike was new. The manual had said to adjust carefully, 1/16th of a turn of the adjuster, and I'd tried all that...
Last weekend, despairing, I took it apart fully.. And noticed, for the first time, a "rippling" towards the pivot end of the main hinge lever. Didn't feel right... Or good. First time I'd noticed - I'd been focusing too much on adjusting rather than checking parts...
Look more carefully, with a torch... Is that a crack or a scratch?
Take it off. It's a crack alright, clearly visible from the underside:
How the hell I hadn't spotted this I don't really know... In my defence, the cracking was only really easy to spot once I'd totally removed the part and could inspect it properly.
Frame joint repair kit ordered from CH White, and has made it to me in Poland today. Totally replaced the hinge, and with minimal adjustment, it's like new. I'd forgotten how "right" the hinge action can feel when adjusted properly. Tolerances here are clearly tight enough to be thrown right out by the bend / crack that I had in the lever. I'm not sure how the crack happened, BTW...
One interesting observation is that the replacement lever is noticeably heavier, and according to my vernier gauge has at least an extra millimetre thickness of metal at the point of failure. That seems prudent.
So check your hinges carefully, Dahon fans. It may not be a question of adjustment if the fold isn't behaving.
