Fox Shocks issues.


Well-known member
Jun 26, 2023
1200 miles in on my Xpedition XP5 and I’m finally getting around to re-springing and shock work. It’s always been known that Polaris springs tend to “sag in”, but a new problem seems to be Fox’s fault rather than Polaris.

We’re finding that shock nitrogen pressure is all over the place, both from a suspension shop we’ve had do shock tuning and from our own experience.

Previous Fox Shocks without a schrader have had a self-healing rubber plug in the nitrogen reservoir cap for checking and charging the nitrogen via a needle setup. Both mine and my brothers Xpeditions haven’t had that plug, and it bleeds out nitrogen as soon as we loosened the screw from the cap. Because of that, we haven’t been able to check actual pressures, but each shock bled off different amounts.

Our solution on my brothers Xpedition was to send the caps to the suspension shop and get them milled, threaded and a schrader valve installed. For mine, I have Shock Therapy extended reservoir caps with schrader valves in them coming.
Since I’m doing the nitrogen charge in the same go as the springs, I won’t really be able to say the difference in ride between the factory charge and a proper balanced nitrogen charge, but I do know it’ll help.

(Just putting this information out there for anyone who might be interested.)
Good to know - let us know how it turns out. FYI since it sounds like you are doing the ST spring kit - their spring dividers have a much tighter tolerance to shock body than factory. I got terrible feedback with any shock articulation from divider rubbing the shock body threads. Springs were clocked according to spec and then I also tried a bunch of different clocking positions with same result. Ditched them and went back to factory dividers and problem solved.
We didn’t use ST for the springs, just my reservoir caps. We got Eibach springs from our local suspension shop. Still using the stock dividers.