I spoke too soon about gravity droppers being reliable. Mine (classic model) has broken… hopefully fixable if I only knew how.

It always locks fine in the middle position, so no issues with the cable or pin presumably.

Depending on how much I tighten the collar, it can either lock in the top position, or the bottom position, but never both on one setting. ie if I loosen the collar it can lock top and not bottom, if I tighten it locks bottom and not top.

What could be going on?

Have you tried loosening off the bottom cap which preloads the spring? Is anything inside the spring stopping it compressing fully?

No, though you’d have thought if there was, that I couldn’t lock it down after tightening the collar, which I can.

…though in desperation to have it working for the dyfi I’ll certainly check that tonight!

Ok the bottom setting is controlled by how tight the bottom cap is. Not tight enough and it wont go down far enough to lock [ spring tension could be an issue but I very much doubt it as for up…you have me there tbh. Is something stopping the full travel of the post?

FWIW I always start by

1. Remove pin – do all three holes line up?- ie can you get to them – use an allen key/screwdriver or something the rough size of the pin to check this

2. Replace pin – remove cable from lever – can you do it “manually” by pulling cable- ie get all three positions.- if not then fettle till you can with cap etc

IME its almost always a problem with cable tension
have you fitted an inline cable adjuster?

FWIW i have not the top [ a rear light was in the way] and not the bottom [ collar]but never only the middle

I’m just about to re-fit a GD and that seems like a very good idea. Ta.

Could be gunk in the holes, or wear- they’re pretty simple things so they usually go wrong in pretty simple ways, if you’re comfortable with it just get it torn apart and fanny about with it.

Ha, got it! For the sake of a future fellow GD owner with the same problem – it was the vertical shims on the inner post which had somehow slipped upward. They banged into the bushing, which prevented the post rising high enough to engage top position unless the top cap was too loose to engage bottom position. Tapping each side with a rubber mallet and screwdriver pushed the shims back down to the bottom of the slots they live in.

Thanks all & once again I have restored my love for the elegant clunky simplicity of gravity dropper…

I just replaced the shims on mine, dead easy if you watch the vid on their site

This kit makes it all feel like new again for 6 quid !
http://www.chainreactioncycles.com/gravity-dropper-rebuild-kit/rp-prod68101

I should add a postscript to this. Knocking the old shims down with a hammer didn’t fix it for long; it went back to its old ways (and then I promptly went and broke the remote mount on the start line to the Dyfi)!

So if you just googled this, don’t bother with that bodge, just order new shims.

I have now purchased the service kit – new shims and seal – also fitted a new cable – also removed rubber boot, put in boiling water and refitted to restore its springiness. And it all works good again.