A bike that bottoms out feels harsh and unstable. The fix is not always a new shock; sometimes it is correct sag, a spring for the load, or a service that restores damping.
Measure sag
Set rider sag with the bike loaded as you ride it. If the correct sag cannot be reached within the adjuster range, the spring is wrong for your weight or load.
Check static sag too. A spring that is too stiff can also feel harsh, but it will not bottom out as easily.
Check travel and clearance
Look at the fork travel and the rear shock for a bottoming mark. Check tyre-to-bodywork and mudguard clearance at full compression. A lowering kit or a larger tyre can reduce clearance.
A missing bump stop or a collapsed bump rubber is a sign of repeated bottoming.
Check damping
A damper that has lost oil or gas cannot control the spring. The bike may bottom out and rebound too quickly. A suspension service can restore behaviour.
Adjust compression and rebound one change at a time and record the settings.
Match the spring to the load
If you regularly carry a passenger or luggage, the standard spring may be too soft. A heavier spring or a different linkage is the correct fix, not maximum preload.
Preload changes ride height, not spring rate. It cannot make a soft spring suitable for a heavy load.
Checklist
- Rider sag and static sag.
- Available travel and bottoming marks.
- Tyre and mudguard clearance.
- Compression and rebound settings.
- Spring rate for rider and load.
- Damper oil and gas condition.
- Linkage and bearing condition.
Questions
Can I fix bottoming with preload?
Preload can raise ride height, but it does not change spring rate. If the spring is too soft, preload alone will not solve it.
Is bottoming out dangerous?
It can be. It reduces grip and can damage the bike. Fix the cause before riding hard or with a passenger.
How often should suspension be serviced?
Follow the maker's guidance and shorten it for hard use or high mileage. Oil and seals degrade.
