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  1. #1
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    Lefty Carbon SL 110, 15mm less travel?

    I have a Scalpel carbon 2008 with a Lefty Carbon SL 110. Pressure about 120 psi. When I lock the fork and pull the wheel downwards the fork extends 15mm more. If I undo the lockout the fork jumps 15 mm back.
    I did a bearing reset several times without result. Last monday I had it checked by a technician at the Cannondale factory in the Netherlands. They said it was normal behaviour and after a while it is some sort of sag.

    When I change the pressure to 200 psi the fork fully extends without help.

    What can I do about it? When riding it feels the forces are not forward anymore, a bit downwards. So it takes more energy to ride.

    I also have a Taurine SL 2009 with a Lefty Carbon SL 110 opi. This forks is normal and extends like it should be. It rides also much more plush than the other Lefty.

  2. #2
    LA CHÈVRE
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    How much do you weigh and what size is your bike? Your Lefty has a negative spring, it's a coil that compresses the Lefty, that pulls the wheel up. It's use is to help the Lefty to work on small bumps mostly. That spring is size specific, it has to match the range of pressure you'll use.

    If the spring is too strong for your weight and the air pressure you put in, it will do as you describe as the air pressure is not strong enough to counter that spring, to balance perfectly the main spring (air) and negative spring. It will also make the Lefty's travel feel a bit rough, too stiff...

    My guess is that you don't have the right spring for your weight in the 08 Lefty. I had the same issue when I got my Scalpel 08, it was a medium, I weigh around 70kg but the Lefty was for a Large bike so it did exactly what you are experiencing. I changed the spring and shim stack to fit my weight and it was heaven, much more efficient and plush.

    The 09 version uses the Solo Air technology so it doesn't have a spring, it uses air for both the main spring and the negative spring, you add pressure to both when pumping the Lefty so they both always match each other.

    DAN.GEROUS.NET : MOUNTAIN BIKING : CYCLOCROSS : ROAD :

  3. #3
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    Thanks for your answer! It explains a lot to me.

    My weight is 190 lbs and my height is 5.8".
    I was told to have the heaviest preload spring, a black one. When searching this rating for preload springs comes up:

    KF213/RED listed as firm 150-169 lbs. rider weight
    KF213/BLK listed as X firm 170-199 lbs. rider weight
    KF213/BRN listed at XX firm 200-220 lbs. rider weight

    A black one looks right for my weight. I'll ask about having the heaviest spring (which apparently is not the black one)

    Then, the question remains about the 15mm.

  4. #4
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    The springs you listed are for the MAX 140.

  5. #5
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    Update.

    I had the fork checked by a mechanic at Cannondale 2 weeks after the date of the startpost. After checking he concluded there was nothing wrong. The forks internals were excellent which was normal after riding so little.

    I did some more pressure in the fork, 140 to 150 psi. Now the "sag" became less and less. After a while the fork was normal again. Which means fully extended when there's no load on the fork. I've decreased the pressure to 130 which is better.
    I hope the fork keeps working normal now.

  6. #6
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    I did ride without bothering (trying to )

    After some time the fork was like it should be. And the difference between my other lefty became less and less. So the problem is solved. Maybe interesting for anybody who has the same and searches this forum

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