MTB Air Fork Insert
MTB Air Fork Insert
MTB Air Fork Insert
MTB Air Fork Insert
MTB Air Fork Insert
MTB Air Fork Insert
MTB Air Fork Insert
MTB Air Fork Insert
MTB Air Fork Insert
MTB Air Fork Insert
MTB Air Fork Insert

MTB Air Fork Insert


Plug and play insert for mountain bike air forks, powered by activated carbon.

Reduces progression, improves grip and comfort, and unlocks more travel. Experience a coil-like feel without the weight penalty and with the tunability of air.
Heavy rider (90+kg) or on E-bike? Choose our Short model where available.

    🔧  Support with setup

    📦  Free UK Delivery

    🤙  Money back guarantee*

    🌍  Free International Delivery for orders of 2 or more

Token Length:

If out of stock, allow up to 15 working days processing time.

IMPORTANT: Taxes and duties for orders outside UK are charged at checkout.

Activated carbon plug and play insert that installs like a token, but acts to increase the effective air volume of your fork, resulting in a more linear and less speed sensitive response. Our first edition inserts are assembled in our workshop, and tested and validated with our dynos and our team of test riders. 

What it does for your ride

  • ⚡️  Better grip, comfort and small bump compliance without compromising sag 
  • 💪  Linear, coil-like feel but with the adjustability and weight advantage of air
  • 🤙 Unlocks more travel - make full use of your suspension
  • ⭐️  Makes the fork more consistent and predictable by dramatically reducing speed sensitivity

Choosing between standard and short

Short variants have more ramp up, and are more suitable in the following cases:

  • ✅  Heavy rider (over 90 kg with gear)
  • ✅  Ebikes
  • ✅  Run 3 or more tokens as your preferred setup
  • ✅  Run high pressure (100 psi or more)
  • ✅  Aggressive style / frequent bottom out  
  • ✅  Typically ride large jumps where extra bottom out resistance is needed 

how it works

The activated carbon contained in our inserts acts to increase the effective positive chamber air volume in your fork. This happens due to its high porosity and internal surface area, that traps and releases air molecules, mitigating changes in pressure (more information on that process can be found on our Technology page). The effect is similar to what happens when you remove tokens: the spring rate is more linear, with less ramp up. This may be hard to believe, because it is a solid material after all!

The activated carbon in our inserts exchanges heat with the air, which mitigates the temperature changes in the air and dramatically reduces its speed sensitivity, resulting in a more consistent and predictable feeling.

When using our inserts, the charge pressure is usually increased, to achieve similar pressures at the end of stroke compared to the original setup. This results in the right amount of support, but with improved tracking, bump absorption and comfort provided by the more linear spring rate.

in the media...

pinkbike magazine

"trutune suspension inserts unlock more travel"

"When I first heard about it, I thought it was a joke, but after talking to the engineers at Carbon Air, the company behind TruTune, I realised the physics was sound. Now I've had the chance to ride it and, at the risk of giving away the ending of this review too soon, it does what it promises."

singletrack magazine

"the tardis token"

"With the TruTune installed I can finally get modern big negative air chambered fat-legged forks to perform better. It doesn’t give you everything that a coil fork does but it certainly improves things massively. If your bike has a 38mm fork on it that you can’t quite get to do the things you need it to do, a TruTune MTB AIr Fork Insert is totally worth a look."


TruTune form part of the setup on the Pole Voima reviewed on Pinkbike magazine.

"I called in a Carbon Air insert to make the Zeb more linear and upped the pressure to 72 psi. This allowed me to use more of the travel on big hits while sitting a little higher in the travel, which better matched the feel from the rear."

Read Article


Our technology was nominated for Pinkbike's innovation of the year 2021, after our prototypes were tested by Seb Stott.

"This one's a lot harder to explain. I thought it was a joke when I first heard about it. But Carbon Air has been used in the air suspension of Audi's luxury sedans for years.In short, its aim is to make air suspension work more like a coil. It does this by using activated carbon, which can be made from sawdust and has the counter-intuitive property of mopping up more molecules of air per cubic centimetre than the same volume of empty space. It acts as the opposite of a volume spacer - effectively increasing the volume of an air chamber."

Read Article


Use of TruTune components may invalidate any warranty with the original equipment manufacturer.

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