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  1. #1
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    Lefty w/ a non-Cdale 1.5 HT frame???

    I am thinking about getting a Sinister Ridge frame, which has a normal 1.5 inch headtube. I would love to be able to put my 2005 Lefty (aluminum) fork on it. Is there any way this can be done?

  2. #2
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    Everything is possible but the Headshok/Lefty headsets needed to run a Lefty is not a OnePointFive standard, it's slightly bigger. I know there are a few options to put a OnePointFive fork on a Lefty sized headtube but not the other way around: I'm not sure there is a headset that converts OnePointFive headtube to the Lefty 1.53" size so you may have to go through the same hassles as if you were to fit a Lefty to a 1,125" headtubed frame. Usually, that means having to replace the Lefty's steerer for a standard OnePointFive steerer and making custom shims to go between the steerer and the Lefty's clamps...
    Last edited by Dan Gerous; 03-13-2006 at 02:05 PM.

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  3. #3
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    The only thing i can think of is...

    Get some 1.5 to 1/18 headset reduction cups...
    Get a lefty to 1/18 reduction stearer addapter....

    This will all work but ull be running your forksetup as a 1/18.....

    Which defeats the object of having a .5 headtube frame in the first place.

  4. #4
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    I thought Cannondale frames have a 1.5" standard headtube, only the headset is different (1.5" standard outer diameter, and just a tad larger than 1.5" standard inner diameter). So I would say yes, you can put a Lefty in your frame if you use a Cannondale Si headset. Maybe Mendon can chime in to confirm or correct me if I'm wrong?

  5. #5
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    Quote Originally Posted by qwackers
    The only thing i can think of is...

    Get some 1.5 to 1/18 headset reduction cups...
    Get a lefty to 1/18 reduction stearer addapter....

    This will all work but ull be running your forksetup as a 1/18.....

    Which defeats the object of having a .5 headtube frame in the first place.
    No point downgrading to the 1.125", it's not harder to convert to 1.5".

    You could also have custom clamps made on your alu Lefty (if the clamps are bolted on, not if they are bonded) that fit directly on a OnePointFive steerer tube. Either way, you will have to make sure your frame's headtube and the OnePointFive headset fit between the Lefty's two clamps.

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  6. #6
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    Quote Originally Posted by Boozzz
    I thought Cannondale frames have a 1.5" standard headtube, only the headset is different (1.5" standard outer diameter, and just a tad larger than 1.5" standard inner diameter). So I would say yes, you can put a Lefty in your frame if you use a Cannondale Si headset. Maybe Mendon can chime in to confirm or correct me if I'm wrong?
    Yeah, I'm not absolutly sure myself, but the inside diameter of the Cannondale might be the same as the OnePointFive standard, the 'deepness' might be different though, not sure. If a Cannondale SI headset fits a OnePointFive headtube, then it's an easy one and Colodude only has to get the Lefty and the headset, slap it on the frame and be prepared to have fun!

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  7. #7
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    Quote Originally Posted by Colodude
    I am thinking about getting a Sinister Ridge frame, which has a normal 1.5 inch headtube. I would love to be able to put my 2005 Lefty (aluminum) fork on it. Is there any way this can be done?
    You should have no problem. A Cannnondale/Lefty headset will go right in a 1.5 inch headtube.

  8. #8
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    That is what I am thinking also.

    I think using a Cannondale SI headset on the 1.5 frame will work. However, we are talking about a spendy mistake if we are wrong. Try getting a new Si headset, and chicking out the HS and the frame with calipers. I think it is a go. Mendon?
    gfy

  9. #9
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    There is one really big problem you need to address, headtube length. Every cannondale headshok headtube is the exact same length 4.5". If your head tube is longer then this I don't think there is any way to do this. If it is shorter you will need to make custom cups. The diameters for 1.5 and headshok are the same, all you will need is a pair of cups ($20 tops for the pair) and bearings if you don't have them already.

  10. #10
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    According to the Sinister site, the headtube length for the small Ridge frame is 4.5 inches. I measured the length of the space between the clamps on the fork and it is 5.5 inches max. So if Cannondale headtubes are 4.5 inches, it looks like a go.

  11. #11
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    So here is what I have figured out so far...

    The Sinister Ridge has a 1.5 headtube. The Cannondale headset has an OUTER diameter the same as a regular 1.5 headset, but the INNER diameter is different. The only thing that matters is the OUTER diameter being the same as the Ridge frame, so the C-Dale SI headset should fit fine in the Ridge frame, and fit the Lefty inside. Correct?

    The Ridge headtube length is 4.5 inches. Cannondale headtube length is 4.5 inches. The amount of space between the crowns on my Lefty is 5.5 inches. I am pretty sure there will be enough room for the headset in there. It will be a snug fit, but it should work. Does anyone have a measurement of how far the headset cups stick out of their frame?

    Now a few more questions...

    My Lefty does not have the bearing that is pressed on the steerer tube. Can a normal bike shop press this?

    Also, for the Lefty to fit on the Ridge frame, that bearing will likely have to be pressed to the very bottom of the steerer, almost touching the crown. Will it work that low? From looking at pictures of complete Prophets and Rushes, the bearing is already pressed that low, so it should work.

    Lastly, does anyone know the A-to-C height of the Lefty Max 140? I would like to figure out what the geometry will be.

    Thanks to all that have replied! There is no way I could have figured all this out on my own. Hopefully the project will go smoothly. If all works out, this should be a very fun bike!

  12. #12
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    Fork crown height for the Lefty Max 140 is 510mm and a SI headset cup is 10mm high (just the part that sticks out of the frame).

    You just need to have the headset pressed in the frame, then, installing the Lefty is very easy.

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