Volume Spacers (Tokens): Effect, Number & Fitting
Volume spacers, often called “tokens”, are small plastic parts in the air chamber of a fork or shock. They are cheap yet change how the suspension behaves noticeably: it becomes more progressive and bottoms out less often. Here you will learn how they work, when they make sense and how to find the right number.
How volume spacers work
An air spring behaves like a pump with its outlet blocked: the further it compresses, the more the pressure rises. This behaviour is called progression. It makes the suspension firmer on big hits so it does not suddenly bottom out.
A volume spacer fills part of the air chamber. The remaining volume shrinks and the pressure climbs faster towards the end of the travel. The start of the travel, which handles small bumps and the SAG, hardly changes. The result:
- The suspension offers more resistance at the end of the travel and bottoms out less often.
- If needed you can run slightly less air pressure and still keep reserves. That helps small-bump response.
- If you remove a spacer, the suspension becomes more linear. The full travel is reached more easily and stays more sensitive.
When volume spacers make sense
- The suspension bottoms out often although SAG and air pressure are right. You can see it from the O-ring on the stanchion or shock shaft: after every normal descent it sits at the very end and you hear a bang.
- You ride heavy, fast or in rough terrain, over jumps and in bike parks where big hits are frequent.
- You want to run less pressure without the suspension bottoming out.
- The other way round: If you never use the travel even on big hits (the O-ring stays far from the end), the suspension is too progressive. Remove a spacer or lower the pressure.
How many make sense
| Component | Typical range | Note |
|---|---|---|
| Fork (air spring) | usually 0 to 3 | One or two are often fitted from the factory; observe the manufacturer's maximum number |
| Shock (air chamber) | usually 0 to 2, in small steps | A shock's air volume is small, so a spacer has a much stronger effect than in a fork |
Always change only one spacer at a time. On a shock even a small change is often enough for a noticeable difference. The limits the manufacturer gives for your model are binding. More spacers make the suspension harsh at the end and stop you using the full travel.
Fitting and testing
- Release the pressure: Let all the air out of the air chamber before opening anything. On the fork usually via the valve on the left leg, on the shock via the air chamber valve.
- Open the air chamber: Unscrew the air spring cap, on the shock the air chamber. Keep sliding surfaces clean and apply a little lubricant if the manufacturer requires it.
- Fit or remove the spacer: On forks the spacer is usually clipped onto the air spring shaft; shock spacers are pushed into the chamber. Only use spacers intended for your model.
- Close up and build pressure, then recheck the SAG as described in How to set SAG.
- Ride the same route: Compare how often and how deeply you use the travel (O-ring), and whether the suspension still bottoms out on big hits. Note the result in My bike.
- Adjust: If it still bottoms out often, add a spacer. If you hardly use the travel, take one out.
Coil spring: no spacer needed
Coil shocks and coil forks have no air chamber and therefore no volume spacers. There the spring rate matters, and the progression comes from the bottom-out bumper and the rear-suspension kinematics. If the SAG is wrong, a different spring rate helps. The suspension calculator estimates a suitable spring rate for you.
Frequently asked questions about volume spacers
What does a volume spacer do?
It shrinks the air chamber. As a result the pressure rises more steeply towards the end of the travel: the suspension becomes more progressive, bottoms out less often and supports better on big hits.
How many spacers make sense?
Usually one to three in the fork and a small spacer in the shock. More is not better: too many spacers make the suspension harsh and stop you using the full travel. The manufacturer's stated maximum applies.
Does a spacer change the SAG?
Hardly, because SAG is determined by the air pressure in the first part of the travel. Still, reset the pressure to your SAG after fitting, because a spacer raises the pressure in the mid-stroke slightly.
Calculate starting values for your suspension →