I’ve got a really nerdy query about rockshox motion control dampers if anyone can satisfy my curiosity. I was a bit concerned that the damper in my fork was not working properly, so I’ve compared it to an identical one out of another fork and they both have exactly the same ‘feature’ that I initially thought might be damage.

I can see how the damper adjustment (and ultimately lock out) works with the aperture at the bottom being opened / closed by the action of the adjuster knob.

However, on both the dampers I have, the bit at the bottom that opens or closes the aperture moves a couple of millimetres independently of the adjuster. I assume this is something to do with protecting the fork if it is accidentally ridden over rough ground with the lockout on? So it can open a bit under extreme compression even if the knob is fully turned to lockout?

I don’t think both the dampers have the exact same fault, so if anyone knows for sure, please let me know.

IIRC the “float” is part of the blow-off (floodgate) feature. As you tighten the floodgate you increase the spring pressure on the vlave at the bottom, making it harder to blow open.

What you’re worried about is normal.

The idea is that the whole moco shaft (the plastic bit) deforms and shortens with compression load.

I think the bit of movement in the washer is to allow oil to flow out of the compression circuit on rebound.

Cheers both.

On finding that two dampers move by the exact same amount independently of the adjuster I was pretty convinced that it was intentional, but I still had a slight nagging doubt.