Formula has a new way of adjusting the air spring of their suspension forks – but it’s not just another hard plastic spacer. Wanting to offer something that allowed for a more gradual suspension curve without the harsh ramp up of a traditional volume spacer. First starting on the project back in 2011, Formula is finally unveiling Neopos – a compressible volume spacer.

Formula Neopos offer a new take on suspension fork volume spacers

Looking a lot like the elastomers used in older forks, the Neopos (meaning New Positive) are designed to be dropped into the positive air chamber of all Formula 35mm forks. Unlike rigid volume spacers, the Neopos simply float inside the positive air chamber rather than being attached to the cap or the air spring assembly. Up to three Neopos can be installed regardless of fork travel.

Formula Neopos offer a new take on suspension fork volume spacers Formula Neopos offer a new take on suspension fork volume spacers

One of the big claims of the Neopos system is that the compressible spacers allow for a more gradual increase in air pressure. This supposedly allows for a more linear suspension curve with more midstroke support and less of a harsh ramp up toward the end of the stroke.

Formula Neopos offer a new take on suspension fork volume spacers

Formula also points out that the response of traditional air suspension is not constant like that of a coil spring. Air spring progression curves will vary with different speeds of compression so to compensate, the Neopos have a consistent expansion time. This is said to impart a more coil like feel to the suspension with a more consistent, and predictable feel.

Formula Neopos offer a new take on suspension fork volume spacers

In contrast to the somewhat complicated technical explanation, installation couldn’t be simpler. Just let out the air from your fork, open the top cap, drop up to three Neopos in, and close and air it back up. Formula says that the Neopos will work with all of their 35mm forks – the Selva, Nero R, and Thirty-Five, and as of May 2018 Nero Ar forks will include two Neopos in the positive chamber. Otherwise, you can buy a set of three for $36 immediately.


    • Marc L on

      It feels like a partial step towards the MRP, which is speed-sensitive and offers external adjustment. So cheaper/easier/(maybe) lighter but not necessarily the same.

  1. Tom on

    Intriguing. Need hands-on review. Formula, do you have any formal position on fitment to other forks (RS Pike, Fox 34, etc., etc.)?

  2. Fritz on

    If the Neopos doesn’t expand at the same rate as the fork rebounds then when the fork starts compressing again the starting volume will be different than the prior hit. With numerous fast hits would the Neopos be compressed more each time, not expanding fully between hits, reducing its effectiveness after subsequent hits?

  3. Tom on

    seems like this product adds asymmetrical hysteresis to the system, which seems like a pretty tough thing to tune properly.

  4. JBikes on

    Their pictorial depicts the same expansion time when compressed to the same fixed point. I.e. expansion time is (logically) the same if I compress to “x” volume in 10 sec vs compress to “x” volume in 1 sec. It’s logical because you are always compressing to “x”

    Pictorials aside, expansion rates are always the same for an air fork and are dependent on air pressure and rebound damping. All this does is alter the air pressure curve in a “non-linear” (obviously a normal curve isn’t linear, but you get what I’m saying) fashion compared to a standard fork (spacer or not).

    What this does seem to provide is “non-linear” response with regards to compression speed As there is some minor delay in compression of the spacer compared to stroke, it will act like a bigger spacer on high speed impact, and impart a artificially steep spring rate. It also is a variable size spacer as it gets smaller as you move deeper into your compression stroke. Its easy to install too.

    Finally, under what mechanism does an air spring rate vary with the speed of compression? Maybe I’m missing something, but this make zero mathematical sense according to gas laws that I know (maybe if you are exceeding sonic velocities?).
    Compression damping is the only thing I know that varies with speed of compression.

  5. JBikes on

    One other question. If its semi-permeable/porous, how is oil kept from slowly fouling it up.
    There is oil in the air chamber that gets aerosolized. I’d assume it would eventually saturate the pores of this things and change its properties to a more rigid (oil being incompressible) structure.

    I’m not negative on the idea. Its ease of installation alone is nice and I’m sure it feels different from a plastic/metal spacer, but some of the explanations on this product seem iffy.


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