jackbucz

Hello, I recently bought a used 2015 Ghost Kato 3 off craigslist, and i took it out for the first time on a ride yesterday. when i would look down later during the ride, it would appear that my sag was at about 70%, rather than the 20% i set it for. My friend confirmed that it was much lower than it was than when we left the parking lot. after I noticed this, we decided to go back to the car and pump the shock again thinking that the shock may be leaking air. This did help it, but the psi seemed much higher than it was when i originally set it up. we headed back out, and hit some fairly technical trails, and on our way back, I noticed that my shock was really low again, so we headed back to the trailhead and packed up. Now this is where things get weird, once i got home after about 2 hours and took my bike off, the rear shock felt just fine and was at about 20% sag... Anyone know what could be the possible problem? Thanks.

Cyclist0108

I'm no expert, but it sounds like cavitation.

https://bikerumor.com/2017/07/21/sus...n-performance/

jackbucz

I though that cavitation was cause by low pressure to begin with in the shock, which would then vaporize the liquid within the shock forming air bubbles. not sure though, thanks for the info.

Kapusta

I am not quite following all you have said, but is it possible that air leaking from the positive to the negative chamber (and then back) could be causing this?

dsaul

I agree that it is probably a bad air seal and air is leaking out of the air chamber and into the rest of the shock. When you stop riding, some of the air makes its way back into the air chamber. The shock needs to be rebuilt.

obrentharris 

Hard or sticky seals that loosen up with use? They could resist sag when cold but loosen up to allow full sag when softened up by use.
Brent

jackbucz

thanks to all who commented. I replaced the main air seals and now the shock is working like new. Thanks for the help all! Jack