Does your RockShox fork sag slightly without you riding it? Do you occasionally find yourself wishing the fork would stay higher in its travel? The new DebonAir upgrade could be the solution! We’re here to tell you how it works, what it costs and how to instal it in your fork.

The new RockShox DebonAir Upgrade Kit replaces the shaft nut and the seal head of the air spring. As a result, the fork should sag less and stay higher in its travel.

In our 2018 suspension fork group test, the RockShox Lyrik RC2 was crowned Best in Test. It already featured the so-called DebonAir air spring and if you were an owner of an older PIKE, Lyrik or Yari fork at the time, you would have been able to upgrade your fork with this new air spring assembly. The advantages it offered back then were a more sensitive response and more mid-stroke support thanks to a bigger negative air chamber. However, RockShox hadn’t yet resolved the issue that some forks sagged by a few millimetres without the rider onboard. The latest update promises to have addressed this – and even more.

The new upgrade is compatible with all Lyrik, PIKE, Yari and Revelation models with 35 mm stanchions

Why do RockShox forks tend to sag by a few millimetres?

To understand what the new upgrade does, you first need to understand the internals of the fork. Situated inside the right-hand upper tube is a notch or dimple, which is there to equalise the air pressure between the positive and negative air chambers. This dimple is positioned in such a way that the equalisation happens with the fork sagged, that is to say at approximately 25% into its travel. However, due to the increasingly large negative air chamber, the fork tends to contract by a few millimetres if the negative air chamber has a higher pressure than the positive air chamber.

As seen here in the upper tube is the notch to equalise the positive and negative air chambers. Until now, this equalisation could only take place with the fork sagged.

How does the new DebonAir upgrade work?

Since it isn’t possible for RockShox to move the position of the equalisation notch in the upper tube, they’ve simply moved the air spring piston upwards by lengthening the shaft nut of the air spring shaft. That way, the piston and the equalisation dimple are lined up with the fork fully extended. As a result, the latest DebonAir upgrade allows the positive and negative air chambers to equalise with the fork extended instead of at 25% sag. On the one hand, this has the advantage that the fork will no longer contract, seeing as the air chambers are always able to equalise. And on the other hand, the air chambers don’t need additional equalising when putting air into the fork.

With the new DebonAir assembly (bottom), equalisation now takes place with the fork fully extended due to the lengthened shaft nut placing the air spring piston higher up

Does the new positioning of the air spring piston change the performance of the fork?

A clear advantage of the DebonAir upgrade is that the fork will no longer contract. However, due to the higher position of the air spring piston, the positive air chamber shrinks minimally while the volume of the negative air chamber increases. To compensate for this, the seal head of the air spring (red in the picture above) has also been modified to move the seal upwards. That way, the only time you would notice the increased progression caused by the smaller main air spring is when you bottom out. However, RockShox have also thought of a solution for this: the bottom of the new seal head is hollow on the inside. The hollow seal head increases the volume inside the lower leg compared to the old DebonAir unit, seeing as the air chamber in the lower leg also acts as a mini air spring and has an influence on the fork’s performance, which many people aren’t aware of. However, due to the increased volume of the lower leg, it’s spring action is weaker and according to RockShox, the fork should offer the same overall bottom out feeling when combined with the smaller and thus more progressive main air chamber.

In order for the performance of the fork not to suffer when you bottom out despite having smaller positive air chamber, the new seal head of the air spring is hollowed out at the bottom. As a result, the air volume in the lower leg is increased.

How to install the new DebonAir upgrade?

There are two ways to install the new DebonAir upgrade. Riders with an old Lyrik, PIKE, Revelation or Yari with 35 mm stanchions – without the DebonAir assembly – can buy the complete air spring unit including the latest upgrade and install it as described in our step by step guide. If you already have a DebonAir air spring in your fork and would like to install the upgrade, simply follow the same step-by-step guide and install the new seal head and shaft nut on the existing DebonAir shaft. It is important that you use Loctite on the shaft nut. Setting up the fork remains unchanged. If you want to know how to find the perfect setup for your suspension, we’ve written a very detailed setup guide.

If you already own a DebonAir air spring, simply remove it from the fork and replace the seal head and shaft nut. It’s important to use Loctite when securing the shaft nut. For everyone else, you’ll have to buy the complete 2021 DebonAir air spring assembly and install it as described here.

What does the new DebonAir upgrade cost?

As with fitting the upgrade, the cost depends on whether you already own a DeboAir air spring. If you already own a DebonAir unit, you only need the new shaft nut and seal head for € 29, but if you’ve got the older, black air spring, you will have to buy a complete 2021 DebonAir unit for € 47.

Two small parts designed to improve performance. The recommended retail price of the shaft nut and seal head of the air spring is € 29.

Our opinion on the new DebonAir upgrade

Unfortunately, we haven’t yet been able to test the new DebonAir upgrade extensively. However, the first impression is very positive. The positive and negative air chambers are able to equalise with the fork extended and we weren’t able to observe any contraction. If your fork is due a service anyway, we recommend investing a few euros for the upgrade kit, especially if you haven’t yet installed the DebonAir unit.


For more information head to sram.com/en/rockshox

We’ve installed the 2021 upgrade kit on a 2020 RockShox Lyrik and are busy testing it – our full review will be available soon.

Words & Photos: Christoph Bayer

About the author

Christoph Bayer

When work doesn't feel like work, then you've probably done everything right. Luckily, that’s exactly what Christoph did. He loves biking and the tech talk surrounding it (to the detriment of his girlfriend Toni), photography and travelling the world. He has been with ENDURO almost from the start and as editor-in-chief, he's responsible for making ENDURO the most progressive and exciting magazine in the industry. Of course, he still writes a lot of content himself, reviews almost 100 bikes a year and rides his bike almost every day. The alpine trails around his hometown serve as the perfect testing grounds. He doesn't have a classic 9 to 5 routine – sometimes he's in the office, sometimes he'll take his laptop to sit in the garden and sometimes you'll even find him working remotely from his van parked at one the best riding spots in the world. For Christoph, work-life boundaries are fluid and he likes it that way.