Just been out for a quick ride on a bike I don’t use that often and noticed an odd sound coming from the rear shock that certainly wasn’t there last time I rode the bike.

On compression it’s “whistling” almost like there is air blowing out from a hole somewhere during the compression stroke.

The shock seems to be fine otherwise, held pressure fine over the ride, damping and pro-pedal circuits both working perfectly and the bike felt completely fine. No exterior signs of a leak or damage.

Any ideas what could be causing it?

Whistle or squeak? And does it occur in both the platform and open positions? An “airy squeak” that occurs when the platform is on is normal. Apparently.

Definitely a low pitched whistle, it occurs in both positions with all levels of pro-pedal, however the pro-pedal does make it better, but only I guess because the shock is not moving as much….

I had that when the pp lever was in the centre position. Fortunately it seems to have gone away. It was silent for years then just appeared one day after a tune at TF.

Like I say though it has disappeared of its own accord. That Said I tend to ride either fully on or fully off so no big deal if it returns so long as it works.