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Thread: Epic Issues

  1. #1
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    Epic Issues

    I've been riding my Epic for a couple weeks and I have a couple concerns.

    #1 I feel like it bottoms out way too easy. I have enough PSI in the Fox shock for a 200lb person but whenever i hit a big bump i use up all the travel. Granted I'm used to freeride bikes, but is this normal? I thought the shock would be more progressive and have some bottom out resistance? Should I be worried about damage?

    #2 My Avid Juicy 5's are going weird. My rear break is super, but my front break vibrates under stress. I have HFX 9's on my other bike and they are smooth when I apply the brakes. On my Epic, under lots of stress, they shake the fork and wheel and feel like its only gripping every other inch on the disc. Is it still being broken in? or is something wrong?

  2. #2
    bang
    Reputation: Cyco-Dude's Avatar
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    how much sag are you getting? how big are these bumps?

    front brake, might need to be repositioned. maybe the rotor is weird. check out the brake forum.

  3. #3
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    Quote Originally Posted by acrylucs
    #1 I feel like it bottoms out way too easy. I have enough PSI in the Fox shock for a 200lb person but whenever i hit a big bump i use up all the travel. Granted I'm used to freeride bikes, but is this normal? I thought the shock would be more progressive and have some bottom out resistance? Should I be worried about damage?
    The air pressure recommendations in the manual are a.) recommendations and b.) much too low for most people when sag is set properly. They're just a starting point. Set sag to 10mm and you'll be happier. This bike will still bottom out occasionally, it only has 3.5 inches back there.

    #2 My Avid Juicy 5's are going weird. My rear break is super, but my front break vibrates under stress. I have HFX 9's on my other bike and they are smooth when I apply the brakes. On my Epic, under lots of stress, they shake the fork and wheel and feel like its only gripping every other inch on the disc. Is it still being broken in? or is something wrong?
    Had the same issue with Juicy Sevens, as did a lot of people. For some reason that brake set sometimes gets harmonic oscillations in the front with some riders and some bikes. I weigh about the same as you...the lighter guys in my LBS couldn't duplicate it when they rode it. (This makes sense from a system dynamics point of view.) Went through several attempts to fix it without replacing anything, the vibrations finally went away when I replaced the Avid polygons with Hayes V-notch rotors. Remove the oscillatory input and you eliminate the oscillatory output.

    Oh yeah, and the Hayes rotors are a much harder metal. I couldn't get the Avids to stop screeching all the time anyway, but the Hayes are perfect.

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    thanks for the replies. I'm sorry I should have been clearer, i actually 155lb - so lots more pressure than i need. I have virtually no sag, or at least very little. the bumps that can bottom out this thing are maybe 2-3inches high...i usually am careful to get a smooth ride, but everynow and then....

    Thats really interesting that you switched to Hayes rotors...I may have to do that. I'll check the brake forum too. As for the rear shock..will bottoming out cause damage?

  5. #5
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    Quote Originally Posted by acrylucs
    thanks for the replies. I'm sorry I should have been clearer, i actually 155lb - so lots more pressure than i need. I have virtually no sag, or at least very little. the bumps that can bottom out this thing are maybe 2-3inches high...i usually am careful to get a smooth ride, but everynow and then....
    Ah I see. Well, in that case you may have the opposite problem. Are you sure that you're actually bottoming out on bumps that size? You may be happier with less pressure then. I know its counter-intuitive, but I've marched down the same path you're going (and in the opposite direction with too little air) and still found that the 10mm sag tends to be just right. The Epic doesn't use much sag, but it should still have it so the shock travel is in the right place to begin with. Over the last three years I've found that this bike is maybe overly sensitive to rider weight and shock pressure changes...having it set up right makes a *big* difference in ride and performance.

    Another aspect of this, particularly if you're coming from a free ride setup, is that the Epic shock is way more progressive than longer travel bikes. No way around the fluid mechanics of it with a short stroke air shock. I've never owned an SJ, but one of the things that gets me during test rides is how much more linear and "bottomless" the shock feels. You may not actually be bottoming out your Epic, but with really high pressure and a progressive curve it may feel like it.

    FWIW, I weigh ~205 and run around 115-125psi for 10-15mm of sag depending on what I'm doing, and rarely bottom out the suspension even on small jumps. But it often feels like it bottoms out, just because of the brain and the short travel.

    Thats really interesting that you switched to Hayes rotors...I may have to do that. I'll check the brake forum too.
    It worked for me! The brake forum has a lot of other solutions that may work for you, like beveling the rotors or using copper grease on the backs of the pads. Worth trying anyway before spending more money.

    As for the rear shock..will bottoming out cause damage?
    There's a negative air spring that will prevent the shock from truly bottoming out, i.e., piston contact. The air seals are pretty hefty for what they do and I've never read about anyone blowing them out, so I wouldn't sweat it. Try setting the sag at both ends and see if its any different for you...

  6. #6
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    Also...

    About the front vibrating. Don't forget the obvious. Headset, and attachment points for the calipers. A loose headset and or slightly loose caliper mounts can most definitely cause vibration in the front brake. It's a safety issue.

    Most likely a rotor or pad contact problem, but check the headset and contact points as well.

    Cheers
    And don't do the burrito jump... Francois

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