My Dahon has cup and cone bearing retainers front and back. The cones are adjustable on the threaded axle and should be just tight enough to allow a slight amount of play between the wheel and the axle.
They were HORRIBLY overtightened. You could feel the bearings bind when you turned the wheel.
I just backed off on the cones and the wheel was fine.
According to many people that have posted about this problem, it is widespread. Remember, the people that assemble your bike may not be knowledgeable bicycle mechanics.
...and I got the Dahon from a LBS that I thought would know better!
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