Every suspension fork needs a spring. Most trail forks ship with air, while coil remains popular with riders who prioritise traction and consistency. The differences are easier to see side by side.
Air vs coil at a glance
| Air spring | Coil spring | |
|---|---|---|
| Spring rate | Set with a shock pump | Change the coil |
| Progression | Tunable with volume spacers | Mostly linear |
| Small-bump feel | Good, depends on seals | Very supple |
| Weight | Lighter | Heavier |
| Heat on long descents | Can change feel | Very consistent |
Bottom line
Air is the flexible, lighter default. Coil is worth it if you ride long, rough descents and value consistent traction over easy tuning.