My wife's Dahon Jack initially has a super tough hinge to move and rotate even though it was a new bike I needed to really wrench it to fold, this is with the latch completely unscrewed and flopping around! But a solution to this was since the bolt hole is open underneath this bike I flipped her bike over night added a few drops of synthetic motor oil and left it there for the next two days to let it seep in. After that the folding was much easier and after a few years it's still great. When I was looking for a daily commuter I knocked dahon off my list because of this and went to either the Brompton or Tern, Their hinges are like opening and closing a light room door! Totally different quality here on how hinge design goes such a long way!