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  1. #1
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    Reputation: ickyickyptngzutboing's Avatar
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    Epic Brain Air Pressure?

    Hey all,

    I just finished building up a bike around a new '04 S-Works Epic frame. I just got the drivetrain adjusted today, and the brakes are set--two things left to go now, well three. I only need help with one (first two are get some zip ties and protective tape and to bed the brakes in), that is, what should I be running in the rear shock for air pressure? As has been stated, the search function is kaputt, and I can't find any viable information online for what air pressures are recommended. I just had an '03 Epic, but I forgot what pressure I was running in that shock as well.

    So alas, I am here. I'm about 130-135# (haven't weighed myself in a lil' while) and I do true cross-country type riding, so if ya'll don't mind chimin' in I would really appreciate it. Also, I don't want to mess around with the rebound too much before I get the right pressure, but just as a hint to get started, where are you running with the rebound setting?

    Cool, thanks for the help!
    waaahoooooooooooooooooo

    Calvin : Ahhh, another bowl of Chocolate Frosted Sugar Bombs! The second bowl is always the best! The pleasure of my first bowl is diminished by the anticipation of future bowls and by the end of my third bowl, I usually feel sick.
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  2. #2
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    Reputation: EPICYZ's Avatar
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    Here you go

    Rider Weight: 130-140lbs. Shock Pressure: 71-74 psi. Rebound: 18-16 clicks from closed

  3. #3
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    Reputation: Cyco-Dude's Avatar
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    common question; do a forum search (unless it's broken, which it probably is heh).

    half your body weight in psi to start with; you want about 10mm of sag. rebound is something you'll have to play with trail-and-error.

  4. #4
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    I ride 04 Epic, run 105 psi , can't remember clicks now. weigh 185 lbs. Check your rubber O-ring on the shock. you want full travel. if O-ring ever pops off the shock , add a little more air.

  5. #5
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    Thanks all for the response...

    I did eventually find the manufacturer's numbers (lightbulb!), but I know there are always a few little tricks that will work at least a bit better. Personally, that much rebound was way too much for me, and I had to dial it down a bit.

    Ok, the bit on the sag was interesting, I remember that you're not really supposed to have sag with this shock, or at least 10mm seems a little bit. On my '03 Epic I remember have very little (If any) sag, and on the '04 I am having some sag. Also, I've noticed that the shock as a whole has some side to side play (it rotates from side to side) another thing that I don't remember from my previous bike.

    Thanks for fielding my questions, and yea, I tried searching, but after 10 failed searches I was like... eh, whatever, I'll face the wrath of my internet counterparts.
    waaahoooooooooooooooooo

    Calvin : Ahhh, another bowl of Chocolate Frosted Sugar Bombs! The second bowl is always the best! The pleasure of my first bowl is diminished by the anticipation of future bowls and by the end of my third bowl, I usually feel sick.
    Hobbes : Maybe you shouldn't use chocolate milk.
    Calvin : I tried Cola, but the bubbles went up my nose.

  6. #6
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    Quote Originally Posted by ickyickyptngzutboing
    Ok, the bit on the sag was interesting, I remember that you're not really supposed to have sag with this shock, or at least 10mm seems a little bit. On my '03 Epic I remember have very little (If any) sag, and on the '04 I am having some sag.
    Both bikes should have been set to have the same amount of sag The air pressure recommendations are merely a starting point. Just because you weigh the same as someone else doesn't mean your weight will be distributed the same way, and the bike really does ride much better when its tuned properly.

    The right way to set the bike up is by setting sag to 10mm. There's more at work than just spring rate here. The damper piston and swing arm are in the right starting point in their travel there as well. I'll sometimes adjust my air pressure 5 psi either way to get a little different riding characteristic, but I've found that the bike is really sensitive to proper sag setup.

    Also, I've noticed that the shock as a whole has some side to side play (it rotates from side to side) another thing that I don't remember from my previous bike.
    The Brain shock is suspended at both ends by a spherical bearing so that it can rotate freely as it moves through its travel. Its not designed to resist torque at all, only compression. Your old Epic had the same setup.

  7. #7
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    Quote Originally Posted by ickyickyptngzutboing
    Ok, the bit on the sag was interesting, I remember that you're not really supposed to have sag with this shock, or at least 10mm seems a little bit.
    the shock isn't fully locked out, just very very firm. when set up properly, the shock will slowly sag. this was covered in the epic manual. 10mm is about 25% sag (the shock stroke was 44mm on the older epics; i don't know if the '06 have more now that they have 100mm of travel instead of 90mm of previous years).

  8. #8
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    Thanks again for the responses... I just like to really understand the mechanics behind it all--especially when it's something that I own.

    TXNavy - Yea, I noticed the spherical pivots, I just wanted some reassurance that play is acceptable. I really don't remember the '03 Epic having play, which is why it led me to this question.

    Cyco-Dude, thanks for bringing up the Epic manual... I had downloaded the '04 Epic manual and the '04 Shock manual from Fox... the two only showed pressure and rebound information. However, I downloaded the '05 Epic Shock Set-Up manual, and that shows the infomation that you're talking about. Since it only mentions the Threshold Adj, I can assume that this set-up will work perfectly for the '04 as well?
    waaahoooooooooooooooooo

    Calvin : Ahhh, another bowl of Chocolate Frosted Sugar Bombs! The second bowl is always the best! The pleasure of my first bowl is diminished by the anticipation of future bowls and by the end of my third bowl, I usually feel sick.
    Hobbes : Maybe you shouldn't use chocolate milk.
    Calvin : I tried Cola, but the bubbles went up my nose.

  9. #9
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    Reputation: Cyco-Dude's Avatar
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    it should; the '04 and '05 had the same shock as far as i know.

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