How To Adjust Air Volume Spacers In MTB Forks | Mountain Bike Maintenance

How To Adjust Air Volume Spacers In MTB Forks | Mountain Bike Maintenance


– Most suspension forks available today are for a range of adjustments
to get enough feeling just the way you want and the most obvious options out there tend to be air sprung. As well as adjusting the
air spring in the fork to suit your body weight, you can adjust compression
rebound damping, but also the air volume. Air volume adjustment
takes care of the initial break away force under small bumps and how the fork ramps
up through bigger hits. So, with the Rockshox Yari and the Fox 34, we’re gonna demonstrate how to change the air volume of your fork. (GMBN jingle) What are volume spacers? Volume spacers like these
are small plastic spacers that instal into the
air chamber of the fork. Now, what they do is decrease
the size of the air chamber, basically by increasing and
decreasing the air volume. By doing that, you make the
fork feel more progressive. Before air spacers like
these, you used to do this by adjusting the oil heights. Had the same effect, bit
more fiddly to adjust and a lot messier. Thankfully, fitting air
volume spacers is very easy. (jazzy music) Why do you need to adjust
the air volume in your forks? Okay, so, when you’ve got
your sag set up correctly, you wanna monitor how much travel you’re using on your
fork on a regular basis, and also, in some of demanding conditions, and then you wanna ask
yourself a few questions. Do you use all that travel and how often? Do your forks feel too
firm and uncomfortable? Do they dive too much in
cornering or under braking? So, the riding characteristics of a fork with no volume spacers in will feel slightly more
linear to one with spacers in. Air itself, when it’s in a confined space, is naturally progressive. It means it ramps up the
more you compress it. However, certain forks with
different lengths of travel and that can feel quite
linear and the effect of that is you’ll feel quite firm
at the beginning of travel, the initial break away
force to make the fork move, and you might end up blowing
through that travel too much. While some riders like that, it might not suit the
riding style that you have. If you like riding hard
terrain, jumping, dropping, stuff like that, you want the fork to ramp up more towards the end of travel. By installing volume
spacers into the fork, you’re making the fork ramp up and firm up towards the end of travel and you’re also making
the fork feel different through the rest of the travel. It’s possible to make the fork
sit up more in the mid-stroke so the fork will feel more
controlled under braking or into turns and, also,
the initial break away force is gonna feel slightly less. So, the floor feels super
grippy and really comfortable. So, we’re gonna do your air volume spacer adjustment on a Rockshox fork. First, this is a Yari,
so we need to do that or the relevant spacers you put inside. A 24 mm socket to undo
the top of the fork, shock pump and some suspension grease. Okay, so, a step before you can do this with the fork on the bike– I’m just doing this with my steerer tube clamped to the work
stand, just to show you. So, first thing’s first
is remove your air cap on the top of the fork and
attach a shock pump to it, so you can note down the air
pressure that’s in your fork. This will make it easier when setting the fork back up again at the end. It’s to get you out on the trail quicker. So, I’m just gonna attach
the shock pump to the fork, take note of the pressure that’s in there, and just let the air out. (air hissing) That is done. I’m just gonna check that it’s all out just by depressing the valve itself. (air hissing) Okay, that’s fully deflated. Now, using the 24 mm socket, make sure it’s a decent
socket, nice sharp edge because you don’t wanna damage
the top of the fork here. You just wanna undo this on the top. (tool ratcheting) Again, take your time. You don’t want the tool to slip. This is an aluminium top cap. Okay, now it’s ready to remove and that is your air top cap. Now, the Rockshox system is very simple. All you need to do is simply
screw in the required amount of spacers that you want into the top. They’ve got plastic thread on them, so you don’t wanna over tighten them. If you feel you need to nip it up tighter, there’s an eight mm allen key
socket on the inside there, so you can just stack them up as you like. I’m gonna put three into
this Rockshox Yari fork. Have to bear in mind
that in certain forks, you can only fit a
certain amount of spacers. For example, the 200 mm travel boxer you can fit 4 spacers,
whereas you’re gonna fit six in a 29 inch, 120 mm fork. So, just check the chart on
the Rockshox website for that. Now, just before you instal them, get into the fork. Just wanna put a little bit of grease just on the O ring around the top. And then, instal it back
into the fork again. Just make sure that sits in straight. (tool ratcheting) And, that’s how simple it is. And noting the air pressure that you released from
the fork to start with, just connect the shock pump and reinflate. So, there you go. It’s that simple to
instal bottomless tokens air volume spacers into a Rockshox fork. Of course, I put three
into this particular fork and that’s the way I
like this fork set up. It’s down to you. Experiment a bit, try a single
spacer, try two or three. You gotta figure out
what feels right for you. (jazzy music) Okay, now we’re gonna
look at the same process, but with a Fox 34. So, it’s very similar and they also use plastic spacers inside. And instead of having a 24 mm
socket on the top, it’s a 26. Equally as important with a Fox is to make sure you’ve
got a good quality socket that won’t round off the top of your fork. First up with a Fox is
to remove the air cap, same as a Rockshox. And then you just wanna
attach your shock pump, take note of the pressure
that’s in there for later on, and then just deflate the fork. You might find that you
can’t get all the air out with the shock pump. You might need to sort of
depress the valve afterwards. (air hissing) If you do that, just be careful. (air hissing) Now, using the socket, carefully remove the top cap of the fork. Again, make sure it’s a quality socket and make sure that it
connects properly at the top. You do not wanna round
the top of this off. (clanging) As you can see on this fork, it’s actually got two
spacers inside already. Gonna add an extra one to that. The Rockshox units screw together. The Fox ones just simply
clip together. (clicks) Just like that and
there’s just the case of applying a little bit of
grease just to the O ring, just like we did with
the Rockshox offering. And then, reinstall. Carefully line up the threads, screw the top cap back into place, and tighten with your socket. Now, simply reinflate just
to the desired pressure and you’re good to go and hit the trails. (air pumping softly) Okay, so that was using
a Fox 34 as an example for installing air volume spacers. Nice and simple. The same with the Rockshox. Hit the trails, experiment, see what it feels like
with one, two, three. Find your sweet spot and then let it rip. Hopefully, that’s been an
informative video for you and you’ll be inspired to
do exactly the same at home. If you wanna know a bit
more about this stuff, so click up here if you wanna
see fork lower leg service, really good practical video. Works on the Fox and
on the Rockshox option. And if you wanna see some
tubeless setup mistakes, click down here. Click on the globe to subscribe. There’s brand new video every single day and, of course, if you like the video, give us a thumbs up.

100 thoughts on “How To Adjust Air Volume Spacers In MTB Forks | Mountain Bike Maintenance

  1. #askgmbn can you use rockshox oil on fox suspension or fox oil on rockshox suspension? or will it damage the seals?

  2. If you buy an EVOl fork, isn't putting in volume spacers just doing the exact opposite you paid extra money for? Extra volume fork with volume reducing plastic, sounds contradictory to me.

  3. Ok so once you add too many of the fox tokens, how do you take them off? Is there a special way, or do you have to be the hulk?

  4. Doddy always comes through with the no B.S. tech info and know how .. love that guy… how do you give like fifty thumbs up ?

  5. Doddy how dare you I'm disappointed in you I can't believe you used a torque wrench to undo the air chamber I almost threw up and cried why doddy why

  6. So I want to get minimum air pressure in the 25kg kids fork that will allow it to return .. yet still not ramp up too fast. I've got once spacer in the 100mm solo air SID at the moment but it still has 10% sag with him off the bike.

  7. #ASKGMBN I own an entry level mountain bike and would like better performance. Should I upgrade parts on my current bike or just buy a whole new bike? Thanks.

  8. My
    fork is rockshox but i can't block it
    I think it's little old model
    So can i change something so i can lock it and unlock it on the road…

  9. #askgmbn Can you guys do a very detailed video going through the process of taking apart an entire bike, including wheels, cockpit, fork, and drivetrain, then putting it back together? I want to take off every part and know what the point of it is, so I guess this would help.

  10. So the spacers only go on one side of the fork? Under the valve? I thought they went on both side, the same amount on each side.

  11. I tried to take the top cap off my Rockshox Pike DJ and once unscrewed I wasn't able to remove it all the way. It was attached to a shaft and I didn't want to pull to hard on this assembly. According to Rockshox's website though I can put two spacers in. What should I do?

  12. Another good video that makes sense. This is what we call a comprehensive guide. Simple video made with clear objective and perfect execution. Great job Doddy! If you can make the same for rear shock that would be awesome. BTW, earning a decent is what mountain biking is all about!

  13. why would you re-inflate the shock to its previous set pressure? Surely after fitting air volume spacers you should decrease the PSI?

  14. The language of suspension is terrible. Ramp up? Progressive? Stand up? It's as bad the three letter acronyms that dominate the corporate world.

  15. #askgmbn @Andrew Dodd
    I've got a RockShox Revelation fork and I'm considering increasing the travel on it from 120mm to 140mm – can you make a video or comment on how that is done? We've seen these bottomless token videos a few times now but never seen anything on GMBN about increasing travel of existing fork.

  16. can you do a video explaining all the various terminology regarding suspension such as what does linear and progressive actually mean ??

  17. nice vid but its a shame it has to be a 24 socket, because i run the same Yaris and want to put spacers in but cant because i don't have the tool

  18. Hello, nice vdo! I've got a Suntour Epixon 100mm fork, can I put volume spacers in it and where can I buy the volume spacers?

  19. Careful Doddy, you'll void the warranty on that Park Tool torque wrench. They're "..not intended for use as a general-purpose ratcheting driver."

  20. Hi there,
    I would appreciate if you could check out my newest MTB edit 😉
    I'm looking forward to hearing any adivces and things i Could improve on.
    Keep on shreddin' :p!

  21. I have recently baught a specialized demo with a bos idylle rare air fork and i have a probleme on it
    I rode it since 3 days without any problems and now the fork is at 20% of the 200 mm and it works nice but when i pull/extend it the fork get back to the 20%
    I looked on internet and it was talking about the positive and negative chamber but i dont want to disassemble it

    What to do /have you got any answer

  22. Was initially put off by doing this myself then saw there wasn't really anything to it so gave it a go on my Yari RC earlier. It had 2 already in there but after a few test runs then adding 1 more it felt so much nicer!
    Cheers.

  23. I bought 2 spacers for my 2015 Remedy 8 only to find out they dont take them in the fox 34 evolution series fork. Was bummed out I wanted to adjust the air volume. Maybe the MRP can work but add 100+$ lol

  24. Hi, I wanted to know if the maximum pressure changes when we change the number of tokens.
    For example the rockshox sid has a maximum of 195psi.
    If I put tokens does the maximum change?

  25. Is there a specific grease made for this? Or can I use Polylube 1000, Parktools? Thanks for the great vids!

  26. #askgmbn
    I have a Fox 34 rhytm fork, which has 150mm of travel, and I don´t know, how many volume spacers should I put there. Could you help me please? Thanks

  27. Don’t rockshox forks and shocks come with volume spacers already inserted at the factory in the case of my specialized stump jumper expert 29er ?

  28. So what is the best way to stop bottoming? Volume reducers or more compression maybe more pressure? Fork is working good but I am clanking it on big hits.

  29. #askgmbntech #askgmbn hey dodd, Is it common to put spacers on 100mm xc bikes? I ride pretty aggressive and feel like a bit of resistance at the end of my travel would help me on jumps and feel safer on drops and fast decents.

  30. Hi i have a question for you i bought trek mountain bike with RockShox judy silver front fork 120 mm travel. I had some problem with that fork so i sent bike to shop to fix it they fix the lockout part but now fork is hard and jerky and just travel may be 80 mm. Shop is not considering this as problem so can u help me what is going wrong with it . Also recommended air pressure to my weight is 120 psi but on 120 psi fork is hard roack .

  31. so by adding volume spacer, it will reduce the amount of travel ?
    let say a fox 36 150mm, If I install volume spacer it can drop to 140mm travel ?
    travel will drop only when you ride or even the bike is on park mode ?

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