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Suntour Raidon air suspension adjustment

BrommoBrommo Posts: 28
edited April 2013 in MTB workshop & tech
I`ve got a Voodoo Bantu which I`m very happy with

I`ve recently bought a decent shock pump as I`ve been bottoming out on my forks now and again so figured I`m gonna have to top up the air pressure in the forks

there only appears to be one valve for adjustment on the bottom of the one fork leg

is this right ? are the forks linked ?

I`m only used to motorcycle forks where each fork leg is independent of the other

cheers folks

Posts

  • cooldadcooldad Posts: 32,599
    One side is the air spring, the other the damping.
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  • BrommoBrommo Posts: 28
    thanks for that

    so only need to put air in on the one side then

    so I assume the forks are linked ?

    anyone got a diagram ?

    done a search on the web but can`t find a diagram for my model of forks

    cheers
  • OuijaOuija Posts: 1,386
    The forks aren't linked. Only one side (usually the left with Suntour) contains the air suspension chamber with the air port at the top of the fork underneath a screw off cap. The right leg typically contains a lockout mechanism and rebound adjuster. The lockout is on the top right of the fork (this can be a manual switch or connected to a remote lever on the handlebar) and the bottom of the right leg usually has a rebound adjuster knob sticking out which sets how quickly the fork bounces back after compression (essentially applies a partial lock to counteract the speed that the air in the left leg wants to throw the fork back up).
  • PlyphonPlyphon Posts: 433
    The lowers are "linked" via the brace and the uppers are linked via the crown :wink:
  • The RookieThe Rookie Posts: 27,804
    By brace one assumes you mean the arch....but not what the OP was asking!
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • BrommoBrommo Posts: 28
    Ouija wrote:
    The forks aren't linked. Only one side (usually the left with Suntour) contains the air suspension chamber with the air port at the top of the fork underneath a screw off cap. The right leg typically contains a lockout mechanism and rebound adjuster. The lockout is on the top right of the fork (this can be a manual switch or connected to a remote lever on the handlebar) and the bottom of the right leg usually has a rebound adjuster knob sticking out which sets how quickly the fork bounces back after compression (essentially applies a partial lock to counteract the speed that the air in the left leg wants to throw the fork back up).

    thanks for that

    just seemed strange not having to put the same amount of pressure in both forks

    I`ve had plenty of motorbike forks apart over the years and each side is identical
  • BrommoBrommo Posts: 28
    Plyphon wrote:
    The lowers are "linked" via the brace and the uppers are linked via the crown :wink:

    there`s always one piss taker :lol:

    as I`ve not had the forks off I wondered whether the top fork brace had a link between the two forks.

    I now know they don`t ! :mrgreen:
  • BrommoBrommo Posts: 28
    1290524936397-k932pvyf10p7-670-70.jpg

    on my Raidons the schraeder valve is at the bottom of the fork so the other side is the rebound

    so the rebound side fork is filled with oil as per this diagram ?
  • OuijaOuija Posts: 1,386
    Probably not. Most of the Suntours i've had to pieces tend to have some grease in the lowers but any oil tends to kept in a reservoir in the bottom of the air spring cartridge, not the bottom of the lowers.

    Any chance of a picture?
  • The RookieThe Rookie Posts: 27,804
    Brommo wrote:
    on my Raidons the schraeder valve is at the bottom of the fork so the other side is the rebound
    Strange as the Suntour manual says it's at the top on the crown as on that Fox...none of the manuals show a Schraeder valve on the bottom, also the bantu I had had it at the top.

    Photo?
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • BrommoBrommo Posts: 28
    Schraeder valve at bottom of right hand fork (lock out on top of the fork)

    IMAG0020.jpg

    and

    left hand fork (rebound adjuster) - not touched yet

    IMAG0028.jpg
  • OuijaOuija Posts: 1,386
    Nope. The rebound adjuster is that thing on the bottom right leg. The hex nut on the bottom left leg is just the nut that holds the fork bottoms on to the stanchions. To remove the fork lowers, you'd need to remove that hex nut and pull out the rebound adjuster knob on the bottom of the right leg (which then reveals an inner nut you can turn with an hex key).

    The air valve is at the top of the left leg under a plastic cap (sometimes aluminium on the higher specced models).

    The cap usually looks something like this strangely ornamental design.

    axon_2.jpg

    and unscrews to reveal...

    20120922_093130.jpg?w=645&h=483

    You can find some basic guidelines to removing the lowers on Raidons, Epicons and Axxons here
  • BrommoBrommo Posts: 28
    think there must be 2 different models of Raidon forks on the Bantu as the air valve is definitely on the bottom of the right leg. I`ve had my shock pump on it

    I`ve had the plastic cap off and there is no air valve underneath (as per your picture). It looks like an allen key way down the fork leg (approx 1/2 way down or so)

    I bought my Bantu form Halfrauds in September 2012 if that helps ?

    rebound is done with a mechanical adjuster not by air pressure isn`t it ?
  • OuijaOuija Posts: 1,386
    Interesting. The only Raidons that Suntour's site are showing with a air valve on the bottom of the right leg (opposite end of the lockout knob) is the X3. If i'm reading it right, it's essentially a spring based fork with the spring being in the left leg and the air in the lower right leg acting as a preload adjuster.

    Typically, suntour spring based forks come with very hard springs that don't really do much (unless your a really heavy rider) and the preload adjuster at the top of the left leg (which merely shortens the spring) never really seems to do that much. It looks like this new Raidon has a lighter compression spring in the left leg and uses a air cartridge at the bottom of the right leg to adjust the preload for your weight (which would make it more adjustable than the old design). Also explains why there is no room for a rebound adjuster as the space is being occupied by the air based preload adjuster. Also explains why it's quite a heavy fork, as there is still a spring in the left leg.
  • BrommoBrommo Posts: 28
    Just been out to look and yes its the X3 fitted

    so the air valve at the bottom of the left leg really only adjusts the rebound

    I`ve done a search and I can`t find the minimum and maximum air pressures for this.

    Any ideas ?

    I`ve downloaded the suntour manual but can`t see these pressures mentioned anywhere ?

    just don`t want to put too much pressure in

    Thanks for the replies. Keep em coming. There`s a wealth of knowledge on this site :)
  • The RookieThe Rookie Posts: 27,804
    No the air valve changes the spring preload (add air, reduce preload), it doesn't effect rebound at all, you have no adjustment for that.

    Set the air pressure to achieve 25% sag and then go from there.
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • BrommoBrommo Posts: 28
    sorry meant preload not rebound

    as you can tell I`m not too up on mountain bike forks !

    just unsure of how much pressure to pump into the air cartridge
  • cooldadcooldad Posts: 32,599
    Enough to get the required sag. Pump, check repeat.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

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  • The RookieThe Rookie Posts: 27,804
    Start at 30PSi and then adjust to get the right sag.
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • BrommoBrommo Posts: 28
    Thanks for all your help

    I`ll adjust the sag at the weekend

    there are just sooo many different types of forks !

    Halfords are still advertising the Bantu as :

    "Forks: 120mm Suntour Raidon air suspension fork with lockout" which is a little misleading as the forks are really spring based with an air cartridge to adjust the preload.

    They are still better than me at present so not complaining but haven`t got what I thought I was getting

    but having said that I would still recommend the Bantu as a entry level MTB. Its certainly given me loads of pleasure :D
  • chez_m356chez_m356 Posts: 1,893
    Brommo wrote:
    Thanks for all your help

    I`ll adjust the sag at the weekend

    there are just sooo many different types of forks !

    Halfords are still advertising the Bantu as :

    "Forks: 120mm Suntour Raidon air suspension fork with lockout" which is a little misleading as the forks are really spring based with an air cartridge to adjust the preload.

    They are still better than me at present so not complaining but haven`t got what I thought I was getting

    but having said that I would still recommend the Bantu as a entry level MTB. Its certainly given me loads of pleasure :D
    this thread may be of interest to you viewtopic.php?f=10002&t=12883452&start=80&hilit=bantu
    Specialized Hardrock Sport Disc 10- CANYON Nerve AM 6 2011
  • The RookieThe Rookie Posts: 27,804
    They are also 100mm not 120mm!

    Of course it is possible that Voodoo haven't correctly notified Halfords of the changes!
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • BrommoBrommo Posts: 28
    chez_m356 wrote:
    this thread may be of interest to you viewtopic.php?f=10002&t=12883452&start=80&hilit=bantu

    yeah I did see that when it came round

    cheers

    to be honest don`t think 20 mm less travel is that much of a loss (to me) to be honest
  • BrommoBrommo Posts: 28
    I e mailed Suntour yesterday at 5.10 pm and got a reply from them today at 9.03 am

    excellent customer service :D

    Benjamin Rees the Vice Sales Manager confirmed "in case of Raidon X3 RL Air or Raidon X3 LO Air there is no adjustability for the rebound. It´s internally preset. The max. air pressure is 10.3 bar (adjustable through the valve on the bottom of the right hand leg)."

    10.3 bar is 149.4 PSI

    thought this may be of interest to some :)
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