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RockShox Pike - Increase bottom out resistance

chris.scotlandchris.scotland Posts: 17
edited August 2007 in MTB workshop & tech
Until a few weeks ago I was the happy owner of some 2003 Dirt Jumper 3's which did everything I could want always using 80+% of their travel and rarely bottoming out. A nice progressive fork. Unfortunately the crown developed two small cracks and started to creak so a new fork was in order.

I picked up a 2005 Pike Race. The first thing I noticed was how unbelievably soft the fork was with the compression damping fully open. Too soft to be useful for the kind of freeride use i give it and needless to say it bottomed out frequently. I have taken to running the fork with the compression knob about 2/3 towards 'lockout' and the gate shut as far as possible. This provides the best bottom out resistance for me.

However I am aware that the gate (or blowoff) is still active and under heavy hits the fork is simply loosing all its compression damping as the gate opens. What I would like to do is to use a higher weight shock oil in the motion control so that I can achieve more compression damping even when the floodgate is fully open. Does this make sense to you guys? Has anyone tried something similar? Or maybe what I am after is just a heavier spring (I am ~160lb with the standard spring)?

What effect would adjusting the oil volume have? I am looking for more bottom out resistance and a more progressive feel.

Maybe the fork needs to go back on ebay and be replaced with some Z1's or something more substantial although I cant really afford to spend more money on this?

Any suggestions welcome.



  • If you've wound on the blue dial and it's still blowing through the travel, it's likely you are too heavy for the spring.
    Get yourself in touch with ...
    Putting thicker oil in there is going to cause spiking problems... Pikes have spiking issues under REALLY extreme conditions, the last thing you want to do is introduce that into normal conditions!!!
    Uturn spring assemblies are around £42, and non uturns are cheaper.
    Shut up. And ride your bike.
    Originally posted by Jon
    As Dave and Alex raced past, someone in the other group of people said 'those two are good'
  • i was afraid you'd say something like that. it seems there is no quick fix and i will have to investigate springs. maybe i can pick one up cheap on ebay sometime - i'll have to keep a lookout.
    thanks for your advice.
  • Is your sag right?
    If not, then it's definatly new spring time.
    Otherwise, the only thing I can think of is increasing oil levels.
    Now you are probably aware that the motion control damper itself is sealed within the top of the fork (stanchion) so don't add any oil in here or you'll be messing with the damping.

    You can just add some oil to the spring side.
    With any open bath fork, you will have an amount of air that sits in the space between the top of the oil level, and the top cap.
    Now obviously when the fork compresses the oil wont, but the air will.
    By increasing the oil volume you limit the amount of space the air has, so will increase resistance at the end of the stroke.
    Be carefull though - too much and you'll find you'll be limiting the travel.
    Stick some thick oil in there, 10 or 15wt.
    Shut up. And ride your bike.
    Originally posted by Jon
    As Dave and Alex raced past, someone in the other group of people said 'those two are good'
  • my sag doesn't seem excessive. i guess you measure it when standing up in the 'attack position' rather than when sitting down?
    i'm going to try and get my hands on some oil and give that a go. i'll just add it little by little and see how it goes.
    thanks for your help.
  • supersonicsupersonic Posts: 82,708 Lives Here
    Note that the floodgate only is effective when the compression adjustment is set to full
  • if so that is great. what is the range of 'full' though? does 3/4 locked still count as full? i will have to play about and test it more. its still quite a new fork for me :p
  • supersonicsupersonic Posts: 82,708 Lives Here
    Full lock is a low speed compression lock, the floodgate is the threshold it blows off. Did you get any instructions with it?
  • yes i understand that, i was just wondering if the blowoff is still active in the intermediate compression settings as well as when fully locked?
  • supersonicsupersonic Posts: 82,708 Lives Here
    The fork will still blowoff under hits, but will not lock at low speed.
  • ye thats what i thought. i wish there was a way to stop that behaviour so that it did not blowoff unless locked. this way i wouldnt loose all the compression damping right when i needed it most - under big impacts.
  • supersonicsupersonic Posts: 82,708 Lives Here
    High speed compression damping is set on these forks - the new mission control damper is adjsutable.
  • ah ok i didnt realise there was a distinction between low speed and high speed damping. i assumed that big blue knob marked compression controlled them both :P if high speed really is damped separately then why do they bottom out more easily when the low speed compression is reduced?
    i guess changing the high speed compression means changing oils which might screw things up and introduce spiking as dave said above?
    thanks for your insight
  • supersonicsupersonic Posts: 82,708 Lives Here
    Its all to do with the internal valving, you may be able to send them to TFTuned and get them revalved for your style. It could be the lowspeed damper is having a little effect on the overall stroke in big hits ie the fork will begin to slow as it reaches the end of its travel anyway due to the spring then the damping kicks in. Or something lol!
  • hehe ye i think i need some expert advice this is getting too much for me :P
    thanks for your help though. i guess the forks could use a service anyway (2005) so maybe i could work something out with them.
    cheers guys.
  • dave_sdave_s Posts: 4,362
    Pikes are really All-Mountain forks but tough with it so it would be well worth checking your spring options.

    By the sound of it if you're cracking crowns a more hardcore fork like 150mm 66s or Z1s as you suggest.might have been a better bet for you

    Personally I really like my Pike 409s on my Cove Stiffee but I'm not a hardcore rider doing big drops I'm just hammering over rocks on mine as best I can and find Pikes are very smooth forks
    Dave S
  • Sag should be about 20%, depending on your preference.
    There is a small amount of High Speed damping, but not much. You can't adjust it, anyway.

    You can try adding oil to the spring side, to try and make them more progressive (this is why Marzocchi forks are good at not bottoming out, have lots of oil!).
    If they are 2005 forks, it may well be worth getting them serviced anyway, TF will be able to tune the fork to work how YOU want it, and sort you out with the correct spring if needed.
    Give um a bell and see what they say, there may be a quick fix they know of they'll tell you about!
    Shut up. And ride your bike.
    Originally posted by Jon
    As Dave and Alex raced past, someone in the other group of people said 'those two are good'
  • cheers guys. going to have a fiddle with the oil levels and also have a word with TF.

    was out riding today and had a great experience with the forks, was mostly cross country but still managed to find a few nice drops at the side of the trail to spice things up :P maybe i just need to get smoother and rely less on the fork! hehe
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