How do I know if my fork is bottoming out?

The o-ring pushed to the end of the stanchion is the simplest sign, but it records only the deepest point of the ride, not how often. A recorded run shows every time the fork reached the end of its stroke, and where.

How much air should I add to stop bottoming out?

RockShox's step is 5 PSI at a time, until the fork feels supportive and stops bottoming out too often. Check sag after each change so the bike still sits where it should.

Can a shock bottom out too?

Yes, and it is read the same way: a shock bottom-out shows as its travel passing 95%, and a run with GPS shows where on the track it happened.

Fork bottoming out: when it is normal

A fork that bottoms out occasionally on the biggest hit of a run is normal; RockShox aims for most of the travel used regularly with occasional bottom-outs on large impacts. Bottoming out on ordinary bumps, or repeatedly in one section, means too little spring or end-stroke support, fixed in 5 PSI steps.

Published 2026-11-11

A bar chart of fork position with one column for each band of wheel travel from zero to one hundred percent, the columns tallest on the left and empty on the far right — A fork that never bottomed out: the tallest columns sit between 25% and 30% of wheel travel and the tail runs out before 90%, leaving the last tenth of the stroke unused.

What bottoming out is

Bottoming out: The fork or shock reaching the end of its travel, where the bottom-out bumper or end-stroke damping stops it. Felt as a harsh, often audible knock when there is too little support left.

Travel that is never used is travel carried for nothing, so the target is not zero bottom-outs. RockShox aims for a soft but supportive feel, using most of the travel regularly with occasional bottom-outs on large impacts.

How often a fork should bottom out

Reading bottom-outs by pattern. The air step is RockShox's: 5 PSI at a time, then ride the same section again.
Pattern	What it means	What to change
Occasionally, on the largest impacts	The travel is being used as intended	Nothing
Repeatedly, on ordinary bumps	The spring is too soft for the rider or the terrain	Add 5 PSI at a time
Only on the biggest landing, harsh and loud	Too little end-stroke support	Adjustable bottom-out, where fitted
Never, deepest point far from the end	The spring is too firm and travel goes unused	Remove 5 PSI at a time

RockShox's adjustable bottom-out gives its forks 8 clicks over the last 10 mm of travel, and its Vivid shock 5 clicks acting on the last 20%. Both change the end of the stroke without moving the sag.

What a recorded run shows at the end of the stroke

A travel histogram counts the time spent in each band of the stroke. Bottom-outs show as a spike against 100%, not as a long tail; a tail that stops short means the end of the travel went unused.

When the run also records GPS, each bottom-out has a place on the track. That is the section to ride again after the change, and the one to compare.

The shock passed 95% of its travel once and the fork twice, each at its own place on the lap: three sections to ride again after a change. An illustration: the track is a lap recorded at Livigno on 18 July 2026, and the three marks are placed.

Auto tuning in the BYB Telemetry software gives bottom-out its own row for fork and shock. On the descent shown in compression and rebound at high and low speed, it suggested slightly less bottom-out resistance at the fork, which points the other way: toward using more of the travel.

How to fix a fork that bottoms out too often

Check sag first: a fork with too much sag starts every hit deeper in its travel
Add air in 5 PSI steps until bottom-outs are occasional rather than regular
Recheck rebound after a 5–10 PSI change; RockShox pairs it with 1–2 clicks
If sag is right and only the biggest hit is harsh, add end-stroke support with an adjustable bottom-out where the fork has one
Ride the same section again and compare where the deepest point of the run sits

Sag is covered step by step in how to measure sag on a mountain bike. On a motorcycle, race sag and the spring check come first, as motocross and enduro suspension setup explains.

Common questions

Is it bad if my fork bottoms out?: Not occasionally. RockShox aims for most of the travel used regularly with occasional bottom-outs on large impacts. Repeated or harsh bottom-outs on ordinary terrain are the problem.
How do I know if my fork is bottoming out?: The o-ring pushed to the end of the stanchion is the simplest sign, but it records only the deepest point of the ride, not how often. A recorded run shows every time the fork reached the end of its stroke, and where.
How much air should I add to stop bottoming out?: RockShox's step is 5 PSI at a time, until the fork feels supportive and stops bottoming out too often. Check sag after each change so the bike still sits where it should.
Can a shock bottom out too?: Yes, and it is read the same way: a shock bottom-out shows as its travel passing 95%, and a run with GPS shows where on the track it happened.