My KS Lev has developed the dreaded sag, and is going back under warranty. The thing is I’d like to ride the bike it’s attached to tomorrow. Does the problem get worse or is the small amount of sag it has now as bad as it will get?

Just ride it.

The 36 mile loop I have planned will be shite if the seat post fails halfway

No reason why it should. It’s just got a little cavitation. Unlikely to have a terminal problem mid-ride.

Cavitation? How so?

Usually happens when bike is lifted by saddle when seatpost compressed. Pulls air in from spring past seals into oil, giving it a bit of unwanted suspension post action.

That’s not cavitation.

Thanks folks, definitely haven’t lifted it by saddle, and there’s a ton of side to side and fore and aft movement as well, so think I’ll stick with the HT and get the Lev sent off. It’s only 9 months the old and not had much use either 😐

KS should replace the cartridge under warranty, no problem. Apparently, they can also be rebuilt if you’re willing to invest the effort:

http://forums.mtbr.com/components/ks-lev-diy-cartridge-rebuild-899659.html

@nobeer – apologies, I understood it to mean air mixed with oil – what does it mean?

OP – 2 yr warranty and rapid warranty service, so they’ll get it back to being like new pretty sharpish.

sillyoldman – Member
@nobeer – apologies, I understood it to mean air mixed with oil – what does it mean?

It can refer to a certain type of fatigue to metal parts, but also refers to gas being drawn out of a fluid. An example: if you crack your knuckles, the noise is gas being drawn from your synovial fluid as you expand the joints. It gives you a 15 – 20% increase in mobility (hence why some pianists do it), which slowly reverts as the gas is reabsorbed. That reabsorption time is why you can’t immediately crack your knuckles again.

If a dropper was based around a fluid that could do that, then the gas would probably get reabsorbed and the sag would disappear… and maybe reappear. Sag in Levs and Reverbs is due to air getting past a seal, not emerging from what’s already behind it.

Cheers nach