Customizing Your Bike Suspension: Mountain Bike Volume Spacers
- Kevin Simart
- Jun 9, 2023
- 3 min read
Updated: Jun 11, 2023
In the mountain biking (MTB) world, fine-tuning your suspension setup is a crucial yet often neglected task. While suspension forks and shocks can sometimes be complicated, expensive, and potentially confusing, there are plenty of simple, inexpensive ways to customize your MTB suspension at home, significantly enhancing its performance. One such method is the use of volume spacers, also known as tokens.
Air Spring Suspension and Its Mechanics
Air spring suspension works based on a simple physics principle - Boyle's Law. In a nutshell, it states that the pressure of a given amount of gas is inversely proportional to its volume when the temperature is kept constant. This means when the air inside the suspension fork or shock gets compressed (volume decreases), the pressure increases, and vice versa.
Understanding the relation between suspension travel and force applied, you'll find that as you push further into the travel of your fork or shock (known as the stroke), you're compressing the air into a smaller space, which makes the suspension stiffer and harder to compress. This change in spring rate throughout the travel is called the suspension's "progressiveness" and where it becomes more challenging to compress, we call this "ramp up" .
Role of Volume Spacers in MTB Suspension
The ramp-up effect is where volume spacers or tokens come into play. By adding spacers into the air spring, you effectively reduce the volume of the air chamber. This means as the suspension is compressed, the air is squeezed into a smaller space quicker, which increases the pressure more rapidly and therefore increases the suspension's progressiveness.
In other words, the more tokens you add, the more progressive your suspension rate becomes - it will be relatively plush in the beginning and firm up more quickly towards the end of the stroke, resisting bottom-outs. This is ideal for riders who are aggressive or heavier, or for those riding steep, rough terrain where larger impacts are frequent.
When and How to Use Volume Spacers
If your fork feels too "divey", or if it's using too much of its travel more than it seems like it should (known as "blowing through its travel"), then adding volume spacers could be the solution. This will increase the firmness towards the end of the travel without making the start of the stroke overly harsh, which often happens if you simply add more air pressure. The same principle applies to rear shocks.
The number of volume spacers you should use will depend on your weight, riding style, and personal preference. Experimenting is key to finding the ideal setup. Start with one spacer and then add or remove based on your ride experience. Remember to adjust one thing at a time and test the setup on a familiar trail to accurately gauge the impact.
Installation of Volume Spacers at Home
Installing volume spacers at home is a relatively simple process, requiring minimal tools. Always ensure to reference your specific suspension manufacturer's guidelines as there can be differences between models and brands.
A general guide to installing volume spacers includes the following steps:
Deflate the suspension completely by releasing all air from the air valve.
For a fork, remove the top cap on the air spring side using an appropriate wrench or socket. For a shock, you may need to remove the shock from the bike and then loosen the air can.
Once opened, you will see the existing volume spacers (if any). To add more, simply snap the additional spacers onto the existing stack. To reduce, remove as necessary.
After adjusting the volume spacers, reassemble the suspension. Inflate the suspension to your desired pressure.
Always remember to reset your sag after any suspension adjustment.
While the process is straightforward, remember that any mishap can affect your bike's performance and your safety. If you're unsure about any step, it's best to consult a professional.
Conclusion
To summarize, volume spacers are an excellent tool to enhance your MTB suspension setup, making it more tunable to your riding style and terrain. They provide an easy and cost-effective way to change your suspension's progressiveness and improve your overall ride experience. Remember, suspension tuning is a fine art that involves personal preference, so don't be afraid to experiment until you find the best setup for
you.
Some useful links:
RockShox BottomlessTokens™ PDF:
FOX Air Volume Reduction guide:
Here is where you can find volume spacers for some of the most popular fork models on the market
RockShox Bottomless Tokens Pike A1/Boxxer B1 (35 mm) (10 Pieces)
RockShox Bottomless Tokens Federwegspacer 3 St. (Dual Position Air) // Pike, Lyrik, Yari
Fox Racing Shox Air Spring Volume Tuning Kit Multi, Float X/DPX2
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