Quantcast

Air shock tuning...technical

Discussion in 'Downhill & Freeride' started by Sandwich, Sep 27, 2012.

  1. Sandwich

    Sandwich Pig my fish!
    Staff Member

    Rep/Likes:
    68 / 829
    Joined:
    May 23, 2002
    Messages:
    15,592
    Location:
    01776
    I'm looking to squeeze a little more performance out of my rear shock on my trailbike. I know this isn't the trailbike forum, but there are more suspension gurus here than anywhere else. Right now I have a Float R on my Cannondale Rush. To my knowledge the bike has a regressive shock rate that makes it perfect for a small volume air shock. Rather than sending my R off to PUSH and seeing what they can do, I've been looking at getting an RP23 to have some more adjustability. The problem is that most of them are coming with HV air sleeves. I'm kind of stuck with PUSH as the Rush has a weird shock stroke (1.75") and I don't inherently trust that I can just slap a spacer on any air shock and be good to go. If I get a HV air can, is there anything I can do to make it more progressive so the bike doesn't blow through it's small amount of travel? Is there any advantage to a spacer and HV air can vs. small volume air can?

    Alternatively, can I swap my LV Float R air can and the HV RP23 air can, if they are both coming on 7.5" shocks?
     

    Please register to disable this ad.

  2. saruti

    saruti Turbo Monkey

    Rep/Likes:
    9 / 67
    Joined:
    Oct 29, 2006
    Messages:
    1,136
    Location:
    Israel
    just dont try to open the inner shock parts....
     
  3. Pegboy

    Pegboy Turbo Monkey

    Rep/Likes:
    13 / 21
    Joined:
    Jan 20, 2003
    Messages:
    1,138
    Location:
    New Hamp-sha
    #3 -   Sep 27, 2012
    Last edited: Sep 27, 2012
  4. Sandwich

    Sandwich Pig my fish!
    Staff Member

    Rep/Likes:
    68 / 829
    Joined:
    May 23, 2002
    Messages:
    15,592
    Location:
    01776
    Hmmm...that doesn't really help with my issue, but it does provide some insight into further tuning options. Those both look to be small air cans.

    I think I need a 'pushing' as my rebound is currently fully opened, and I still wonder if the bike couldn't use a little less. Maybe I just like my rebound fast...
     
  5. saruti

    saruti Turbo Monkey

    Rep/Likes:
    9 / 67
    Joined:
    Oct 29, 2006
    Messages:
    1,136
    Location:
    Israel
    I just got my float R from a service center. (after opening it by myself.... all room got oil on the walls and everything.... my wife want to kill me... I forgot all about the air in the boost valve....)
    the shock got new oil in it, the rebound got faster, and a new propedal screw.
    the guy how serviced my shock is great and knows a lot about air socks.
    my AM bike is also progressive/regressive (ironhorse MKIII)
    so I wanted it to work better on the little staff and feel bottomless.
    so he added a bottom out bumper
    the bike really feels great now.

    I think you can go with the bigger HV can
    and add a bottom out bumper.
    so it will work better in the small staff and feel bottomless.
     
  6. Sandwich

    Sandwich Pig my fish!
    Staff Member

    Rep/Likes:
    68 / 829
    Joined:
    May 23, 2002
    Messages:
    15,592
    Location:
    01776
    Yeah I'm not inclined to crack open the damper internals. I probably COULD figure it out, but I think there's a high probability of me messing something up. I like the idea of being able to turn propedal off for downhilling which is why I want an RP2/3.
     
  7. 4130biker

    4130biker PM me about Tantrum Cycles!

    Rep/Likes:
    64 / 441
    Joined:
    May 24, 2007
    Messages:
    3,921
    Location:
    Lizard Town
    Advantages of a HV would be more tuneability in the air volume department. I agree with Saruti on the bumper idea.
    My RP2 needed to be more progressive, I messed with the air volume and pressure, but the bumper with lower pressure turned out to give the best overall improvement.
    I'm pretty sure the air cans could be interchanged like you suggested.
     
  8. scottishmark

    scottishmark Turbo Monkey

    Rep/Likes:
    16 / 20
    Joined:
    May 20, 2002
    Messages:
    2,124
    Location:
    Somewhere dark, cold & wet....
    HV can + Volume reducers FTW?
     
  9. Steve M

    Steve M Turbo Monkey

    Rep/Likes:
    6 / 23
    Joined:
    Mar 3, 2007
    Messages:
    1,997
    Location:
    Whistler
    Unless you have nitrogen charging equipment, including the Fox needle assembly (which they don't sell to the public) then you won't be able to rebuild it. IFP depths are super important (also not publicly available) and o-ring seals in the damper, should you want to change them, are very sensitive to durometer as well as the fact that you need to find the right size. Add to this the fact that all the parts in the damper need to be torqued to very specific values and you have a lot of reasons not to mess with the damper yourself.

    I would not recommend a HV air sleeve (XV1 specifically - XV2 is even worse) on your bike though. Even with the -0.6 volume spacer, it's still only about the same spring curve as the standard low volume can.
     
  10. Sandwich

    Sandwich Pig my fish!
    Staff Member

    Rep/Likes:
    68 / 829
    Joined:
    May 23, 2002
    Messages:
    15,592
    Location:
    01776
    Good to know, and thanks. I'll stick with the small volume can and go from there.
     
  11. boogenman

    boogenman Turbo Monkey

    Rep/Likes:
    2 / 114
    Joined:
    Nov 3, 2004
    Messages:
    3,439
    Location:
    BUFFALO
    I got my RP23 pushed over the winter and switched to the LV can. It is a s hit ton better now. If you call them up they will let you know if you should change the air can or not.

    Propedal is a joke, stick with your Float R. The push tune is worth every penny.

    FYi: mine is 7.875X2.0

    This is all the crap that Push took out and changed
     
    #11 -   Sep 27, 2012
    Last edited: Sep 27, 2012
  12. Sandwich

    Sandwich Pig my fish!
    Staff Member

    Rep/Likes:
    68 / 829
    Joined:
    May 23, 2002
    Messages:
    15,592
    Location:
    01776
    from my understanding, the floateR comes with propedal ON all the time, vs. RP2/3 where you can turn it off. I don't know if they can remove it, but I like having a lockout on my fork for climbing extended hills.
     
  13. Steve M

    Steve M Turbo Monkey

    Rep/Likes:
    6 / 23
    Joined:
    Mar 3, 2007
    Messages:
    1,997
    Location:
    Whistler
    The Float R has fairly low Propedal settings, trying to balance being closed enough for good pedalling and open enough for good bump absorption, and consequently it's not amazing for either. Unfortunately no amount of custom tuning will fix the fact that it only has one LSC setting, so you'll always be compromising on the trail. I'd definitely suggest an RP23 (or CTD) Boost Valve shock if you can get your hands on one. You may have to shell out extra for a low volume sleeve but it will give you much better options than what you're currently on.
     
  14. saruti

    saruti Turbo Monkey

    Rep/Likes:
    9 / 67
    Joined:
    Oct 29, 2006
    Messages:
    1,136
    Location:
    Israel
    Sandwich
    what is the compression and rebound tune on your sock?
    you can see it on the small stickers on the can.
    my shock come with low tune both comp & rebound.
    so I really liked it, except the bottom out... that now is fixed with the bottom out bumper