6 Best Fork Volume Spacers For Aggressive Downhill Tuning

Nothing ruins a high-speed descent like the harsh, jarring metal-on-metal clang of a fork bottoming out on a square-edge hit. Finding that perfect balance between supple small-bump sensitivity and deep-travel support is the holy grail of suspension setup. Mastering your fork’s volume spacers is the most effective, low-cost way to transform a stock ride into a trail-devouring machine.

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Fox 38 Float Spacers: Best for Big Hits

The Fox 38 is built for the rowdiest terrain, and its volume spacer system is designed to match that aggression. These spacers are relatively large, allowing riders to make significant changes to the spring curve with just one or two additions. They provide a noticeable ramp-up at the end of the stroke, which is essential for riders who frequent bike parks or jump lines.

Because the Fox 38 uses a high-volume negative chamber, it often feels overly linear out of the box. Adding these spacers corrects that, preventing the fork from blowing through its travel on repetitive G-outs or high-speed compressions. If you find yourself consistently hitting your O-ring to the top of the stanchion, these are your primary remedy.

For the rider who prioritizes big-mountain stability over delicate trail feel, the Fox 38 spacers are the definitive choice. They are robust, easy to install, and provide the exact type of firm platform needed for aggressive, heavy-hitting riding. Skip these if you prefer a very light, poppy feel across the entire length of the travel.

RockShox Bottomless Tokens: Best Overall

RockShox Bottomless Tokens set the industry standard for simplicity and effective progression tuning. Their threaded design makes them incredibly easy to stack, allowing for fine-tuned increments that don’t require specialized tools beyond a standard socket. They offer a predictable, consistent ramp-up that works across the entire RockShox air-spring lineup.

The genius of these tokens lies in their versatility for the average weekend rider who traverses a mix of flow trails and technical rock gardens. They allow for a lower initial air pressure—improving grip and traction—while still maintaining the necessary support to keep the bike from diving in corners. This balanced approach makes them a reliable tool for almost any riding discipline.

If you are looking for a “set it and forget it” solution to your bottom-out woes, look no further. Their widespread availability and ease of use make them the best choice for anyone who prefers spending more time on the trail than in the workshop. These are a must-have for every serious rider’s tool kit.

MRP Ramp Control Cartridge: Best Adjustable

The MRP Ramp Control Cartridge moves beyond static plastic spacers by offering a dynamic, tool-free solution. By replacing your standard top cap with this cartridge, you gain the ability to adjust the progression of your fork on the fly. Simply turning the dial changes the volume of the air chamber, allowing for instantaneous setup changes between trail sections.

This is the ultimate upgrade for riders who tackle unpredictable terrain or varied trail conditions during a single ride. You can soften the fork for a technical climb or rooty traverse and then dial in firm, deep-travel support for a steep, rocky descent. It eliminates the need to carry tools or fumble with internal spacers when the conditions shift.

While it requires a higher initial investment than traditional tokens, the performance gains are unmatched for the tinkerer. It provides a level of precision that plastic spacers simply cannot replicate. For those who demand maximum control and versatility, this cartridge is the definitive performance upgrade.

Ohlins RXF38 Spacers: Best for DH Racing

Ohlins brings a level of precision engineering to their volume spacers that reflects their heritage in motorsport. Designed specifically for the RXF38, these spacers are intended to optimize a highly refined air spring system for competitive racing. They provide a nuanced, progressive feel that manages deep-travel energy without sacrificing the fork’s mid-stroke composure.

In a racing scenario, the goal is to keep the bike composed through the most violent chatter while remaining predictable during massive impacts. These spacers provide that stability by keeping the fork higher in its travel, allowing for better geometry retention in steep, sustained sections. They are tuned for riders who are already at the top of their game and need every fraction of a second.

If you are chasing podiums or riding at elite-level speeds, these are the only choice. They aren’t designed for casual trail riders looking to “fix” a bad setup, but rather for those who understand exactly how they want their suspension to perform. For the competitive racer, they represent the final piece of a perfectly tuned puzzle.

DVO Onyx Air Spacers: Best Custom Tuning

DVO suspension products are known for their focus on rider-tunable performance, and the Onyx spacers follow that philosophy. These spacers are designed for precision, allowing riders to fine-tune the progression of the OTT (Off-the-Top) system that DVO is famous for. This allows for an incredible balance between small-bump suppleness and the high-speed support needed for enduro riding.

What sets these apart is the granular nature of the tuning; they allow you to separate the initial “plushness” from the end-of-stroke ramp. You can achieve a ride quality that feels bottomless without needing to sacrifice the initial sensitivity that provides traction in loose, muddy conditions. It is a sophisticated system for a rider who wants a personalized ride feel.

These spacers are ideal for the rider who isn’t satisfied with a “one size fits all” approach and enjoys spending the time to dial in their bike for specific trails. If you possess a bit of patience and a love for technical setup, the DVO Onyx spacers will reward you with a custom ride quality. They are an essential part of the DVO ecosystem for those who demand total control.

Manitou Mezzer Spacers: Best for Enduro

The Manitou Mezzer is a lightweight powerhouse, and its spacer system is designed to keep it performing at that level. These spacers are compact and efficient, adding progression to the air spring without adding unnecessary weight or complexity. They are specifically shaped to integrate cleanly with the Mezzer’s unique air-spring architecture.

For enduro racing and long-distance backcountry riding, the goal is to manage travel without excessive heat buildup or friction. These spacers help keep the fork operating smoothly throughout the most grueling stages, providing a firm, supportive end-stroke that doesn’t feel harsh or “choked.” They offer the perfect middle ground for riders who value a mix of climbing efficiency and descending confidence.

If you ride a Mezzer, these are a non-negotiable accessory for aggressive terrain. They allow you to unlock the full potential of your fork’s chassis, ensuring it stays composed when the trail gets ugly. They are reliable, affordable, and essential for the modern enduro racer.

How Volume Spacers Change DH Progression

Volume spacers work by physically reducing the air volume inside your fork’s spring chamber. As the fork compresses, the air inside becomes more compressed and thus more resistant to further movement. This creates a “ramping” effect: the fork feels plush and active at the start of its travel but becomes significantly firmer as you reach the final third.

A more linear setup—with fewer or no spacers—allows the fork to use its travel easily, which feels great on flat, flowy trails. However, once you start hitting drops, jumps, or heavy braking bumps, a linear setup will frequently bottom out. By adding spacers, you increase the force required to reach full compression, essentially creating an “air cushion” at the end of the stroke.

Understanding this dynamic is key to preventing harsh impacts while maintaining the traction you need. It isn’t just about avoiding the “clunk” at the end of the stroke; it’s about managing your bike’s geometry throughout the entire descent. A properly set-up fork will keep your head angle stable and your weight balanced, even through the nastiest, rock-strewn chutes.

Signs You Need More Bottom-Out Resistance

The most obvious sign that you need more progression is a harsh metallic bottoming sound on trails that feature jumps or drops. Even if you don’t hear a sound, look at the O-ring on your stanchion after a ride; if it is constantly pushed all the way to the top of the travel, you are leaving performance on the table. This is often accompanied by a feeling that the front end of the bike is “diving” or feeling nervous in steep, technical sections.

You might also notice that the bike feels “wallowy” in high-speed, banked turns. If the fork settles too deeply into its travel under cornering forces, it steepens your head angle, which can make the bike feel twitchy and unstable. By adding a volume spacer, you keep the fork higher in its stroke, which maintains the intended handling characteristics of your bike through those G-forces.

• Frequent Bottoming: If the fork hits the end of its travel on drops you clear regularly.
• Instability in Corners: The bike feels like it is diving and becoming too steep during aggressive maneuvers.
• Feeling “Soft” at Speed: The fork lacks the necessary support to track through high-speed chatter effectively.

Step-by-Step Guide to Installing Tokens

Before starting, ensure your bike is clean to prevent debris from entering the air chamber. Always release all the air from the fork before attempting to remove the top cap; failing to do so can result in the cap flying off under pressure. Use the correct socket size—usually 32mm or 28mm depending on the brand—to avoid rounding the edges of the aluminum cap.

Once the cap is removed, thread your tokens onto the underside of the cap or slide them into the air spring shaft as required by your manufacturer. Hand-tighten the assembly to ensure it is secure, then gently re-thread the top cap into the crown, ensuring the threads are aligned and not cross-threaded. A light smear of suspension grease on the O-ring will ensure a smooth seal and easy removal in the future.

After installation, pump the fork back up to your target pressure and cycle the fork several times to equalize the air chambers. Check for any air leaks or unusual noises, then take a short test ride on a local trail to evaluate the change in feel. It is always better to start with fewer tokens than you think you need and add them gradually to find your sweet spot.

Balancing Sag and Spacers on Steep Trails

Finding the right balance between sag and volume spacers is a fine art. Sag determines how your bike sits and tracks over small bumps, while spacers dictate what happens when you push the bike to its absolute limit. A common mistake is to add too many spacers and then lower the air pressure too much to compensate for the mid-stroke stiffness, which results in a “dead” feeling fork.

For steep trails, you want to maintain a reasonable amount of sag—usually between 15% and 20%—to ensure you have enough front-end grip. If you find the bike is still diving, add one spacer at a time rather than drastically changing your air pressure. This keeps the initial plushness for traction while providing the extra support you need to keep the front end up on steep, near-vertical roll-ins.

Remember that trail conditions change with the seasons. A bike that feels perfect on hard-packed, tacky dirt in the summer might feel too stiff on the wet, rooty trails of autumn. Treat your volume spacers as a seasonal adjustment tool, just like you would with your tire pressures. Stay patient, test in small increments, and prioritize a ride that lets you charge with confidence.

Mastering the use of volume spacers turns your suspension from a mystery into a precise tool. By understanding how these small components influence your ride, you unlock a new level of confidence on the most challenging terrain. Keep tinkering, stay observant, and most importantly, get back out on the trail to test your new setup.