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  1. #1
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    Lefty -- weird issue with air spring?

    My son came back from his ride today with his Lefty fork (PBR damper in older carbon 29er) bottoming out badly -- weird since yesterday it was fine. Just felt like it needed air so screwed on shock pump and it pegged out the gauge -- let a TON of air out until it read zero (far more air in it than I thought possible). Pumped it back up to 170 and now it has NO resistance, it just bottoms out with no effort, but it's holding air. Engaging the lockout just makes it harder to push (more resistance) but it still bottoms out. There's only very weak rebound too. What the heck is going on? There's about 500 miles on this damper -- added new by MendonCycleSmith when he rebuilt the fork about 10 months ago. There's no sign of oil leakage. I've reset the roller bearings regularly, certainly every 100 miles at least. Nothing out of the ordinary when I pulled off the top cap and the bearings reset normally. We need this bike operational by Saturday as it's a race weekend for the Colorado High School MTB racing league -- any hope to get it fixed locally? I'm a suspension idiot, so will be taking it to the local shop -- they're good, but not Lefty experts (hence why I send stuff to MendonCycleSmith).
    "The plural of anecdote is not data." -- Attributed to various people in a variety of forms, but always worth remembering...

  2. #2
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    At my shop I saw two cases that come closest to what you describe. Those Leftys gradually lost their travel and would eventually get stuck all the way down unless forcefully pulled back up. What happened, and what I would guess in your case, is air leaked from the positive spring to the negative, effectively equalizing the spring forces. I don't remember how complex the fix was, but Cannondale is aware of the issue and does have resources available to fix it.

    Have it evaluated by a dealer to be sure. The bad news is it will probably take at least a few days to get it fixed.
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  3. #3
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    My Lefty Max 140 converted to PBR did that also. The wavy washer on the air piston was broken. I had the piston replaced. It has been fine now for over a year.
    My name is Chris and I ride a Prophet 650b with a Lefty.

  4. #4
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    Quote Originally Posted by Prophet Julio View Post
    My Lefty Max 140 converted to PBR did that also. The wavy washer on the air piston was broken.
    Thanks! I had a quick reply from MendonCycleSmith that said the same thing -- the wavy washer is the likely problem. He notes that this is a very common problem with the PBR setups installed over the past year (older PBR's aren't so problematic) and that come late November or December there will be a new air piston design that will fix the problem.
    "The plural of anecdote is not data." -- Attributed to various people in a variety of forms, but always worth remembering...

  5. #5
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    I learned something
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