I only ever saw one of these bikes and my memory isn't crystal on this, but: the ball joint eye bolt pulls the seat post up when unfolding, but the seatpost is held up when unfolded by closing the seatpost collar/quick release like most folding bikes, isn't it?





The 'eyebolt' part would not seem to be under any force once the bike is unfolded and the seatpost collar/clamp is latched closed tight.