During oil filling or refilling, shaft cycling, or cap installation, air inevitably becomes trapped in the shock oil.

Air is compressible.
As a result, damping is no longer governed solely by oil, but repeatedly disturbed by trapped air bubbles.
This is not about feeling softer or stiffer — the damping logic itself is broken.

You think you’re tuning.
In reality, you’re fighting variables.

If air bubbles remain in the shock oil, you may experience:

• Sluggish damping response, a vague feel
• Inconsistent performance between left and right shocks
• Identical setups producing different results
• Noticeable performance drift as temperature changes

At this point, swapping oil weights or springs only makes tuning feel more like guesswork.