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  1. #1
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    Air settings for a DHX4 on my Slayer SXC70

    Hi,

    I recently changed the damper oil in my Dhx4 due to some air trapped and old oil. (Mountainbike.nl ? Toon onderwerp - Bye Bye Titus, welcome Rocky Mountain Slayer sxc70)

    And I'm playing a bit with the known air pressures. Only, I'm having way more pressure in my shock compared to a lot of you guys. And I can't figure out way.

    I'm having a 2009 medium Slayer
    I'm 1m85 so quite big for a M frame but I like a bike being small and agile.
    I'm not a real superweight, around 190 lbs geared up.

    Pressure is max in the piggyback, 200 Psi
    Having 230 / 240 Psi in the main chamber

    If I run lower pressures I'm experiencing a lot of pedalbob and to much sag.

    (I like to run my bike quite hard, enduro cups etc).

    Anyone having about the same set up, experiences?

    Thx,

    Michiel

  2. #2
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    The big benefit of the DHX4 was lots of tunability to give coil like shock performance so that longer travel suspension systems with lower leverage could still feel supple in that mid-stroke range just beyond 25-30% sag. The SXC leverage ratio already has that characteristic on its own, so something like an RP23 actually seems to be better matched to the SXC if you plan to ride up and downhill.

    You can see that the leverage ratio is still climbing when the rear wheel is at 40-50mm sag, so it is very supple and compliant in the next 40mm of travel and then turns back to reduce the leverage ratio beyond that so you don't blow through all the last 40mm of travel easily.

    So the tuning you are describing for the DHX4 isn't that unusual for all around riding.
    Attached Thumbnails Attached Thumbnails Air settings for a DHX4 on my Slayer SXC70-rocky-mountain-slayer-sxc-2007_levratio.jpg  

    I'm a member of NSMBA and IMBA Canada

  3. #3
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    Thanks, so I'm not the only one who finds the Slayer's suspension is (too) supple?
    Apart from that it's a great bike and I love it!

  4. #4
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    I had a 2007 SXC Special Edition with an RP3 instead of a DHX4 (same shock as the SXC 50 came with), and I found that it was quite well behaved, and the ProPedal worked quite well. It was plush but pedaled well with no pedal bob.
    I'm a member of NSMBA and IMBA Canada

  5. #5
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    There are a few issues with how the DHX-A performed in general. There are more positive feedbacks with the RP23 than the DHX-A.

  6. #6
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    Seems I have over gonflated the damper a bit. Yesterday took a (shuttle) ride with my friends. One lfted my rearend to let it bounce on the ground, it jumped right back! He told me that's to hard for the stuff we're riding. So I've decreased the pressure in the main chamber to 180Psi. This afternoon another test ride. Will take my suspension pump with me for some playing. I'm scared the pedal efficiency will not be that good with 180Psi in the chamber....
    But then again, the pressure in your damper is relayed to your weight and not to if your bike bounces back or not...

  7. #7
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    Rebound damping controls the bounce back speed. If you push down on the rear end it should have just enough rebound damping that it won't launch the rear wheel off the ground when it rebounds.

    Positive pressure should be set based on sag. With the DHX you might want to go for 20-25% sag instead of 25-30% sag.
    I'm a member of NSMBA and IMBA Canada

  8. #8
    DGB
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    I went from a DHX-Air on my SXC70 to an RP23 as I was getting too much mid stroke wallow.
    I'll agree with Rockyuphill about setting your rebound damping and about setting the sag at the lower value helping the bike to ride higher in its travel and be less susceptible to wallow.
    Another thing I noticed is you run less pressure in the piggyback chamber than in the main. I think it's recommended to have more pressure in the piggyback chamber to prevent harsh bottom out and the minimum pressure for this chamber is 125psi.

  9. #9
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    Thx so far guys. I mentioned my friends they'd told me crappy stuff to regulate the bouncing by more or less air pressure. But I blame myself as well as not having thought better about this.....

    About the Piggyback chamber, to my understanding 200Psi is the maximum pressure for this little canister. (Although I've red articles about putting a little more oil in this chamber which obviously will increase the pressure as well.

    I'm back to 230Psi's in the main chamber and maybe will try 220Psi in the piggyback. The 'problem' I encounter with the piggyback is that it doesn't hold the air pressure to well. After a week of two pressure has lowered to about 160, 170. And you know the valve is a pain in the ass to reach... Does your piggyback also deflate slowly?
    Cheers

    Ps, had my first Enduro race two weeks ago and it was fantastic and my 'old' Rocky helded up very well amongst all other competiters. Some photo's to check out:
    Raid des Terres Noires

  10. #10
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    Another thing to keep in mind is that the piggyback chamber is quite small, so when you connect the shock pump, it fills up the hose and pump gauge, and that is a sizable percentage of the piggyback chamber volume. If you're relying on the gauge reading when connecting a pump to determine what the pressure was before you connected the pump, you will likely be estimating low. So the chamber may have some leakdown, but it likely isn't as bad as you think it is.
    I'm a member of NSMBA and IMBA Canada

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