I'm going to pull the hinge pin today and clean and regrease it. While it seems awfully soon (3 months), the pakiT is folded multiple times each day so maybe it requires a bit more tlc than the hinge pin on my NWT. It definitely sounds like metal on metal rubbing that flexes with each stroke. It does not happen out of the saddle, I don't think, but it is really hard to pedal out of the saddle on the pakiT for a sustained period. Will let you know if it is the hinge pin.