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  1. #1
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    Swooshing sound on Enduro AFR rear shock?

    I'm on my third AFR rear shock on my 2007 Enduro SL and after running this one in for approx 2 months I now notice a swooshing sound on compression (independent of compression/damping setting). I assume it's from the oil being pressed through a damping valve shim...but it concerns me as I am about to head off for a 2 week overseas MTB holiday with this bike... Could this be air bubbles trapped inside the oil or is it about to die?

    Replace / Repair / Ignore? What is your opinion?

  2. #2
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    Quote Originally Posted by Variateur
    I'm on my third AFR rear shock on my 2007 Enduro SL and after running this one in for approx 2 months I now notice a swooshing sound on compression (independent of compression/damping setting). I assume it's from the oil being pressed through a damping valve shim...but it concerns me as I am about to head off for a 2 week overseas MTB holiday with this bike... Could this be air bubbles trapped inside the oil or is it about to die?

    Replace / Repair / Ignore? What is your opinion?
    I have heard lots of suspension componets do this , generally if it is air in the oil it will do it from the get go and the dampining will suffer and not be as controlled .
    Now that it is colder I notice more slight squeeking and knocking from all the different shocks as the different blow off's and shims are worked harder because of the cold thickened oil , --------generally air will sound like you are swishing your mouth out with mouthwash , ---------.
    I like to check my nitrogen charge in the shocks in the cold of winter -----they do condense and show a low charge sometimes ,
    If you do not have a nitrogen tank set up with a needle , you can take the air sleeve off and it should be real hard to press the shock down buy hand if your nitrogen is still up to par.( in fact you can press it together by hand and also listen for air while checking the nitrogen resistance )
    Have you had to run a higher compression setting more so than normal ?
    Did it just start this when it got cold ?
    Does the bike still suck up hits nice and not bottom hard and all work fine
    Generally you will hear the spike valve knocking alittle when blowing open when its cold like this ----can you hear yours ?

    I have had alot of calls latley because it got cold and the fox RP23 will squak really badly on rebound untill it vibrates and spits the spring off the blow off and does bad things in the shock ( there is a replacment spring that cures this ) .

  3. #3
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    If its cold where you are, then it may be something that Kelstr mentions.

    If its not cold, then it may be something else. My first AFR (an 07 model) whistled in the third compression position. Ever since I got the 08 replacement I haven't heard any weird noises.

  4. #4
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    No - it's rather warm here in Summer in Australia....(but I do note a temperature dependency in the AFR fork performance).

    But this can't explain the swooshing souind in the rear by itself, i.e. if warm - the oil should be even less viscous....?

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    If its warm there then i would say give it the manuel push through the stroke by hand to see if you can feel and or hear the air at slow speed , and this will also let you know if you still have a good nitro charge and then at least you will know what it is .( if the nitro is low , the nitro can pass the IFP and get into the oil causing this noise also )

    If it is alittle air it should not cause the shock to fail ,---however if it were mine i would take the shock appart and correctly service the damper bleeding all the air out, replacing the "O" ring on the IFP and re-charging with Nitrogen.

    If you do not want to do that , ask Specialized to warranty it out again for you .

  6. #6
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    QUOTE=kelstr]...will also let you know if you still have a good nitro charge and then at least you will know what it is .( if the nitro is low , the nitro can pass the IFP and get into the oil causing this noise also .[/QUOTE]

    There is no nitrogen charge in the, AFR, rear shock. This is in the front dual crown only. The rear is similar to a Fox shock
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  7. #7
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    My rear afr shock on my enduro has done this since the first time I took it out. Im not sure if it has affected the performance but it only does it on the rebound, on the compression stroke its quiet. Ive had the bike for about 6 months so its been doing it for that long, I dont think there is any problems with it.

    Now that its 40 degrees outside the suspension is stiffening up hardcore.

  8. #8
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    Most Fox shocks and all AFR shocks have a nitrogen charge. Many Fox forks have an 'open bath' system.
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    Quote Originally Posted by wyoracerX
    QUOTE=kelstr]...will also let you know if you still have a good nitro charge and then at least you will know what it is .( if the nitro is low , the nitro can pass the IFP and get into the oil causing this noise also .
    There is no nitrogen charge in the, AFR, rear shock. This is in the front dual crown only. The rear is similar to a Fox shock[/QUOTE]

    There is no NORMAL user or LBS servicable N2 on the shock. Kelstr is not normal.

  10. #10
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    All 3 of my AFR"s made a nasty gurglingi noise once they blew

  11. #11
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    Quote Originally Posted by wyoracerX
    QUOTE=kelstr]...will also let you know if you still have a good nitro charge and then at least you will know what it is .( if the nitro is low , the nitro can pass the IFP and get into the oil causing this noise also .
    There is no nitrogen charge in the, AFR, rear shock. This is in the front dual crown only. The rear is similar to a Fox shock[/QUOTE]
    Oh Really -------I beg to differ , ----------see that little allen head screw at the bottom of most all shocks in the business with that white plastic insert in it --------------unscew that and tell me what you get ------------------the nitro charge of 150 to 350 psi in all shocks is what holds the fluid stable so a piston with a shimstack may be forced through the fluid in order to force open a shim stack and create a dampening force ---------------this is how a shock works .

    I think you need to study the subject alittle more ----------------nitro presurized dampers have been used in suspension since 1940 ----------
    So yes , the rear shock has a 190 psi nitrogen charge in the bottom of it that forces a piston up against the fluid

  12. #12
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    Quote Originally Posted by camarosam
    My rear afr shock on my enduro has done this since the first time I took it out. Im not sure if it has affected the performance but it only does it on the rebound, on the compression stroke its quiet. Ive had the bike for about 6 months so its been doing it for that long, I dont think there is any problems with it.

    Now that its 40 degrees outside the suspension is stiffening up hardcore.
    Actually it wont hurt anything , -------its not uncommon to have some noises in damper assemblies.

    I just wanted to make sure Variatur's situation was ok since his started doing this out of the blue ( which can happen )

    Generally if you have controll over compression and if you can run the rebound all closed and slam the shock down and it almost wont come up --------------your still good.

    It really does not take much to vibrate a shim or spring and or to have just alittle air or nitro in the fluid and it can make a loud sound but really the shock will still work fine.

    I have seen guys ride all sort of shocks with goofy noises in them for years and they work just fine .

    One buddy I ride with all the time has a RP23 on his bike and the dam thing has that dam spring vibration squak everytime it rebounds -----------its really loud and it drives me nuts ------------it will eventually have a problem ---------------but it could take a long long time , and he just loves it because he knows how badly it anoys me

  13. #13
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    Quote Originally Posted by camarosam
    Now that its 40 degrees outside the suspension is stiffening up hardcore.
    That's probably the oil. It won't hurt it to run like that, but if you want it to feel better, get it serviced and have them put in the lightest weight oil that they have.

  14. #14
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    If it wasn't an Enduro AFR shock I'd venture to say it could just be a normal sound, but knowing the tendency for these shocks to randomly implode, my bets are on blown seal inside shock

  15. #15
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    Quote Originally Posted by Yody
    If it wasn't an Enduro AFR shock I'd venture to say it could just be a normal sound, but knowing the tendency for these shocks to randomly implode, my bets are on blown seal inside shock
    There is no seal inside the shock that blows , and they do not randomly implode ,
    If alittle air was cought inside the shock or alittle nitrogen seeped by the IFP on assembly and he has alittle noise , its not a big deal .

    If he still has full control of all the dampining , he can run it untill he can go through it or warranty it off if he want to .

  16. #16
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    Quote Originally Posted by kelstr
    There is no seal inside the shock that blows , and they do not randomly implode ,
    If alittle air was cought inside the shock or alittle nitrogen seeped by the IFP on assembly and he has alittle noise , its not a big deal .

    If he still has full control of all the dampining , he can run it untill he can go through it or warranty it off if he want to .
    Not what my experience has been! I've heard there is a seal that gets dislodged because the tolerances are incorrect or something along those lines. Everytime my shocks blew they would make a nasty gurgily noise. Yeah most air shocks make a little noise but it was my experience everytime I heard an unusual gurgily noise from my AFR it was because it should imploded.

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