FYI good video on this

 

Newer reverbs are way more durable than the old ones. Mine lasted a full year and a half of heavy riding and abuse before needing an $80 rebuild.

First gen I went through like 2 or 3.

To answer the OP - if its sinking suddenly, it likely needs to be serviced. Air still gets where it shouldnt be over time with these posts.

 

There is this with respect to clamping droppers: https://www.pinkbike.com/video/497057/

 

Good video. My LBS warned me when I got a bike in 2016 to never pull up on the reverb when it was in the down position.

My new bike has a round top tube I clamp to and avoid the seat all together. This Stealth has shown zero issues in over a year, feel like I won the Reverb Lottery! Or, more likely, that's just how the B1 posts should be.

 

I thought when the sag on a reverb starts getting worse it is time for a rebuild. No?

 

I wouldn't necessarily think so. My Reverb started acting up when it was just a couple of months sold. In my case, I'm pretty sure it was due to using it as a clamping point for my stand. Since corrected, and now that I no longer use the post for clamping, no more issues. A rebuild wasn't required.

 

...if it's down. It's fine to lift by the seat if the post is all the way up.

 

Correct, and that's what I do. But with the Reverb, seems even extended can cause issues. But to be honest, I don't just hang the bike in a balanced fashion all the time. That doesn't help, and is why I (now with droppers) always clamp to the frame.

 

You shouldn't pull a bike by the seat if you have a dropper, the Reverb is known by developing sag if you lift the bike by pulling the seat.

 

My Reverb started doing the same thing... corrected it... started doing it again. But never really an issue, and it doesn't seem to get worse. BUT... after the second time getting it fixed (method like Lone Rager mentions, BTW), I stopped using the seat post for mounting to my bike stand (as recommended by the RockShox). The issue hasn't returned.

 

Like clamping to the exposed post causes it? Odd... I do that occasionally but 98% of the time I just hang the bike on the clamping arm by the seat so it's not torquing the seatpost at all.

 

^^^ right. Bleeding the remote does nothing for sag as the remote circuit is completely independent and not fluidically connected to what goes on in the post.

It's common for Reverbs to sag several mm when weighted. If it's significantly more than this, one trick you can try is to extend the post, turn the bike upside down, squeeze the remote and press down on the BB to compress the post. Release the remote, turn the bike right side up and then squeeze the remote to extend the post. What this does is move the air from the IFP tube into the reservoir. It's still on the wrong side of the IFP, but not in the IFP tube where it will compress when you sit on the saddle. This is a temporary and imperfect fix as the air will eventually get back into the IFP tube and cause squishiness.

 

It's common for Reverbs to sag several mm when weighted. If it's significantly more than this, one trick you can try is to extend the post, turn the bike upside down, squeeze the remote and press down on the BB to compress the post. Release the remote, turn the bike right side up and then squeeze the remote to extend the post. What this does is move the air from the IFP tube into the reservoir. It's still on the wrong side of the IFP, but not in the IFP tube where it will compress when you sit on the saddle. This is a temporary and imperfect fix as the air will eventually get back into the IFP tube and cause squishiness.

I'll check the air and I'll also give this a try but I'm more than a little perturbed that it may need service after 409 miles...

 

A sagging seatpost usually means that air got into the IFP chamber and the seatpost needs to be bled.
There are several How To online on how to do a bleed on the Reverb.

 

My KS Lev does the same thing. I've tried adjusting the cable, even reinstalled the cable.

 

Well, bleeding a Reverb isn't a big deal if you've got the kit for it, or you can pay your LBS to do it.

 

Did you try adding some air?

 

Try this. Did not completely resolve my similar issue but helped quite a bit and it hasn't gotten any worse. I was about 75psi low.