Ah, do they thread on on the rear too? The drive side cap on mine doesn't do a great job of holding the freehub on, so sometimes the cassette and freehub come loose when the wheel's out of the frame. The freehub seal isn't great at keeping the the muck /water out, so I've got to muck it out fairly regularly. The blue ring that's meant to hold the pawls in has snapped but that's not been an issue. There are some scratches on the freehub and the last time I popped it open 3 of the pawls were stuck down under the springs, however I've not had any problems with it whist riding though.