DISCLOSURE: My wife and I own a bicycle shop that is an authorized Dahon dealer.

There have been random reports on this forum of Dahons with frame hinge problems. But, from what I have read, those seem to be with individual bikes rather than a consistent issue with a specific model. And some of those "issues" can likely be traced to an insufficient pre-delivery inspection or lack of user maintenance. More important, IMHO, is to confirm that the handlepost has been replaced if this is a model that was subject to a recall a couple of years ago.

-HANK RYAN-
Norman, Oklahoma USA