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  1. #1
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    Mojo HD Shock Air Canister Volume

    So the HD comes with a high volume shock, but the old Mojo's all have small volume shocks. I've always been under the impression that the high volume shocks are for more less aggressive trail riders since they offer excellent bump compliancy but no bottom out resistance. I read that Ibis spec' the high volume because that is all that is available from fox in that shock length.

    Now here's where it gets tricky; I've also read that the Mojo HD is tuned for the air shock and not coil, so I would think it would be tuned for the High volume shock as well?? Does the suspension design ramp up at the end of its travel to avoid bottom out?

    Also I'm even more intrigued now that they say you can make a Mojo HD 140 by putting the old Mojo Shock on it, which is a low volume shock. If the frame is built around a high volume shock, does putting on a low volume shock double the ramp up at the bottom of its stroke? Or is the high volume shock really not ideal for the HD if you're riding aggresively but its all that Fox had so they used it.

    Looks like I'll be running the Mojo HD 140 and then eventually just going with a custom tuned coil, that high volume shock seems crappy. (unless maybe you have PUSH install a bottom out bumper?)

  2. #2
    aka dan51
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    Quote Originally Posted by Yody
    that high volume shock seems crappy.
    It's not. I bottom the regular Mojo much easier than the HD, and I run more sag on the HD.
    My only problem with both shocks is the factory tune cannot get the rebound slow enough. I brought it by a Fox tech at MBO and he said it's perfect. Perfect? I'm running it as slow as possible so I don't have any room for adjustment. I have a feeling he didn't want to do any work... Perfect would be the knob is set in the middle of the total clicks so I could speed it up or slow it down. If I had 2 more slow clicks it would be how I want it. So now I've got to dump $250 at PUSH to get it right for my weight, or I've got to lose 30lbs; which isn't safely possible.

  3. #3
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    Why 250? a regular tune is $180, unless you're getting the bottom out bumper installed, which from what you just wrote sounds like you don't need? I pretty much calculate a PUSH tune into the cost of the bike, to me, its just that good.

  4. #4
    aka dan51
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    Last time I looked I thought it was around 225. Have to add in shipping costs too.
    Just checked and it's 159. Now it's sounding more reasonable...

  5. #5
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    travel

    The extra ramp up in the suspension of the HD probably happens in the last 10mm of travel, so the HD 140 can(sic) use a lower volume shock and won't suffer from extra ramp up because it doesn't go to deep into the ramp up zone.

  6. #6
    The MTB Lab
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    Welcome the world of high volume sleeves and their compromises.

    Here is a blurb I wrote about the XV RP23 on a Yeti ASR 7 in a review:

    Another issue which is not Yetiís fault, is that the Fox RP23 rear shock with the High Volume sleeve bottoms out too easily, and having to use some pretty hefty pressures (body weight x 30%) to alleviate the problem isnít the best solution. I think Fox and Rock Shox, need additional design work on their lightweight air shocks to work properly with the longer travel bikes.

    Some one asked for clarification on my statement, so I went into it further:

    Like many other bike manufacturers, theyíre tied to Fox (for whatever reason), the larger stroke RP23ís all use the High Volume sleeve (as does most shock companies), the air sleeves are the source of the problems causing the need to run excessive air pressure, and they bottom out too easily. I think a volume reducer might help some? PUSH Industries is supposed to be doing this with the Rock Shock Monarch at some point in time? Yeti is sort of stuck with what Fox offers, price and design constraints left them with the XV RP23 8.5◊2.5″ (Medium compression). I think Fox needs to do more design work on the RP23 for use on the 6+ to 7″ bikes, since itís roots (the RP23) were more in less than 6″ bikes. I would love to try a coil on the rear, but the weight difference sort of puts a damper (pun) on it. Again, most of the shock companies have been rolling their research into the piggyback and coil systems for these type of bikes.

  7. #7
    _dw
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    There is no low volume 8.5X2.5 available from FOX, and based on how the air spring curve looks for the XV shock that the HD uses, we wouldn't want one.

    Actually, I can put this a better way; the XV long stroke shock on the HD has a similar air spring curve to the small can short stroke shock on the Mojo / SL.

    Dave
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  8. #8
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    So even though this is a high volume shock, it still ramps up at the end? Or does the HD suspension use a different curve than the previous Mojo?

  9. #9
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    Monarch?

    Dave,
    Curious whether the 11 RS Monarch RT3 HV is a good fit for the HD (and the HD140) and which tune (low, mid, high) you would suggest ?

    -Shane
    Any sufficiently advanced technology is indistinguishable from magic
    - Arthur C. Clarke

  10. #10
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    PUSH Industries is supposed to be doing this with the Rock Shock Monarch at some point in time?
    They're en-route to us from the Rock Shox Factory now. We're not releasing any info just yet but if you want early release info you can drop me note at dm@pushindustries.com. We will have three new 2011 rear shock offerings.

    There is no low volume 8.5X2.5 available from FOX
    Actually, Fox does offer 8.5x2.5 standard volume cans. We stock them and I know that some Trek frames come stock with them. Whether you want/need one is a whole other story.

    Darren

  11. #11
    1:18
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    True, the Specialized Enduro 2010 has 8.5" shock and standard/small canister.

  12. #12
    Homer's problem child
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    The HV RP23 can is fine on the HD. I'm 225 lbs geared to ride and running about 230 psi in the rear shock and just about 35% sag. The HD is my everywhere bike. Been hitting some rough stuff on it and getting lots of air time. No issues with bottoming harshly. I use all my travel, but no clanks or jarring bottom outs.

    Impressions without first hand experience are like tit's on a bull. i.e. Useless. Get the bike and ride it, hard, report back.

    So far the standard RP23 with HV can has me wanting little in terms of rear suspension upgrades. I'm coming from several Pushed DHX's, Pushed RP23's and have ridden many different rear shocks. Last bike had an MX Tune VanR on it. Same i-to-i as the HD so I have it to swap over when I want it, but so far the RP23 has met all my needs to date in a lighter package.

    BY.
    When the going gets weird, the weird turn pro....

  13. #13
    _dw
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    Quote Originally Posted by PUSHIND
    They're en-route to us from the Rock Shox Factory now. We're not releasing any info just yet but if you want early release info you can drop me note at dm@pushindustries.com. We will have three new 2011 rear shock offerings.

    Actually, Fox does offer 8.5x2.5 standard volume cans. We stock them and I know that some Trek frames come stock with them. Whether you want/need one is a whole other story.

    Darren
    Yeah, I'm talking more about the stock off-the-shelf part number FOX offerings, unless there's a new 2011 SKU that I should know about.. I'm not sure I can think of a bike that I'd need that for so far, but I always try to shy away from anything "custom" on the shock side when it comes to developing new bike platforms. More options are better for me and most of the people that I work with as long as they are stock items. I'll have to ask Fitzy about that later today.
    dw★link
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  14. #14
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    Still curious how the HD suspension is different than the standard Mojo. Its my undestanding that the Mojo "needs' the small can since the suspension is so linear. How has the HD design changed to work with the high volume if it is changed at all? Is this longer stroke high volume actually ramp up more than the shorter stroke?

  15. #15
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    Quote Originally Posted by Yody
    Still curious how the HD suspension is different than the standard Mojo. Its my undestanding that the Mojo "needs' the small can since the suspension is so linear. How has the HD design changed to work with the high volume if it is changed at all? Is this longer stroke high volume actually ramp up more than the shorter stroke?
    Longer travel, longer stroke shock, seems a larger volume can is consistant with the other size increases.

    I'm glad the large volume was designed, that way a rider can go to a smaller volume if they are bottoming easily with the large, without custom work. Also the rate is closer to linear coil spring, so less problems in bottom travel requiring special rampup spring support as there is the the SL or C.

    DW designed with the only available option at the time, the small volume can to make the SL and C suspenion linear in overall in "wheel-rate" (spring+ link + wheelbase combined leverage ). The HD is linear in wheel-rate, if not rising rate slighlty, with the large volume can.

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