They use some sort of air-filled chamber, the valve us under the saddle and easily accessible with a shock pump. The ‘notchiness’ is a ratcheted system, so it’s a design feature rather than a fault, probably. They have all the subtle recoil of a Lee Enfield .303 rifle, but you get good at subtly weighting the saddle to avoid instant knacker retribution. They also give a relatively poor amount of travel for the overall length projecting from the frame. They also have a tendency to pop past the ratchet stop if you’re not quite deliberate with operation of the post / weighting it as it extends.
On the plus side, they are one of the few droppers with a layback head and mine has been reliable bar a couple of air top-ups. I’ve never serviced it, but it seems like a pretty simple creature, so I’m prepared to believe that it’s straightforward.
I’d stick some air in the thing and see – carefully – if that sorts it out. Be wary of how viciously it will shoot up and adjust accordingly, bear in mind that it is just a violent thing full stop.
If you want a smooth, non-ratcheted, knacker-friendly post, replace it with something else would be my suggestion. I keep meaning to get round to that, but clearly don’t really care enough to actually do it.
