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  1. #1
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    When a shorter Lefty clamp spacing ?

    scalpel 29er seems to open a new path .

    shorter steerer tube .

    now there is a spacer on the upper bearings , Lefty 2011 has the same 138mm spacing between clamps.

    when a "shorter" Lefty ?


    29er crowd needs that.

    for a low front of the bike , specially in M size frames

    my opinion is that Scalpel 29er is however too long ...

    obviously Flash frame needs a lower tube too . 105 - 110 mm will be perfect


    so come on , engineers ... put the upper clamp 15-20-25 mm lower ...

    only question of bonding , or not ?

    HURRY UP !!!
    Attached Thumbnails Attached Thumbnails When a shorter Lefty clamp spacing ?-e1477240-22b2-4316-933b-fe065b4a21985.jpg  


  2. #2
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    I think you'll have to go with a diffent stem to achieve that goal. I think if the clamps start moving around the frame geometry will start getting messed up and then the bikes will start handling like those from another brand.

  3. #3
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    not the clamps nedd to move.

    only the upper .

    try to imagine that picture I posted. no upper spacer , upper Lefty clamp 10mm lower .

    obviously a One piece stem/steerer shorter of same amount .

    ( with separate stem and tube as old Lefties will be easy to do )

    so the bar will be 10mm lower .

    no changes in frame geometry .

    only a racest position of rider .

    same travel of fork , same behaviour .

    or not ??? i see it as very simple to do

  4. #4
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    I see what you're saying now, that wouldn't change the geo at all. Still probably going to need to go with a -15 or so degree stem to fix the issue though. Christoph Sauser used to set his scalpel up with a very negative stem like that. Keep nagging and you might get the ball rolling on some changes!

  5. #5
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    look the spanish guys from Black Cat Bone ...

    they did their own carbon titanium frame and a rigid lefty

    with sliding clamps , fitting both 26" and 29"

    and all the frames too ....

    with PM or IS mount as you prefer
    Attached Thumbnails Attached Thumbnails When a shorter Lefty clamp spacing ?-269071_249411791739121_230554723624828_1136985_4653153_n.jpg  

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  6. #6
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  7. #7
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    Very cool, but I've have no failures on the Cannondale stuff. I'd have to see these things mass produced and ridden for years, before I'd trust one under me.

  8. #8
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    It's a cost thing Eli, cheaper to make a spacer than a new jig for different clamp positions, plus you would loose the interchangeability across the line. Cannondale are a bit too mass production now I think.

  9. #9
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    Quote Originally Posted by sp3000 View Post
    It's a cost thing Eli, cheaper to make a spacer than a new jig for different clamp positions, plus you would loose the interchangeability across the line. Cannondale are a bit too mass production now I think.
    for sure ... but doing a Lefty for the Scalpel 29er frame will be a good thing

  10. #10
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    Maybe that thing is not a spacer but just a different/new kind of upper bearing seal......
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  11. #11
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    Quote Originally Posted by cdalemaniac View Post
    Maybe that thing is not a spacer but just a different/new kind of upper bearing seal......
    its an external bearing. supposedly they have chaged the upper bearing for the 29er scalpel so they can run the actual head tube shorter on the smaller sizes to allow for more standover height.

    im with eli on this. running huge negative rize stems to get the fit right is getting silly... if its technically feasible, cannondale should be making 29er specific lefty's to suit shorter hed tubes.

  12. #12
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    Marco Aurelio Fontana from CFR on his 29er Flash tests has a -17 degrees

    cannot see a Flash in that way ... seems an old retired Concorde

  13. #13
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    Quote Originally Posted by eliflap View Post
    Marco Aurelio Fontana from CFR on his 29er Flash tests has a -17 degrees

    cannot see a Flash in that way ... seems an old retired Concorde
    i have a -20 deg stem...

  14. #14
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    Quote Originally Posted by nathanbal View Post
    i have a -20 deg stem...
    more than a landed Concorde ...

    -15 is from British Airways , -20 is from Air France ...
    Attached Thumbnails Attached Thumbnails When a shorter Lefty clamp spacing ?-concorde_03.jpg  


  15. #15
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    Hi..

    If you (really) want a shorter clamp distance on your lefty, you could to what this norwegian is doing and blogging about on a norwegian mtb forum.

    He starts with an Lefty speed carbon sl w/dlr 110mm travel. This has an a-c measurement of 47,8 cm. His plan is to move the lower clamp 2 cm upwards giving him an a-c of 49.8cm, this will also allow him to keep the 110mm travel according to his measurements.
    Attached Thumbnails Attached Thumbnails When a shorter Lefty clamp spacing ?-66034.jpg  

    When a shorter Lefty clamp spacing ?-66035.jpg  

    When a shorter Lefty clamp spacing ?-66036.jpg  

    When a shorter Lefty clamp spacing ?-66037.jpg  


  16. #16
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    Continued..

    Here are some photos after he has Tig welded the clamp together again, getting ready to paint the clamp and glue the clamp back on the lefty

    So what has he achived. Very light 29er fork, no need for spacers between top of headtube and top clamp = lower front, and keeping the travel 110mm.
    Attached Thumbnails Attached Thumbnails When a shorter Lefty clamp spacing ?-66083.jpg  

    When a shorter Lefty clamp spacing ?-66084.jpg  

    When a shorter Lefty clamp spacing ?-66085.jpg  

    When a shorter Lefty clamp spacing ?-66086.jpg  


  17. #17
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    this is what i search !!!!


    110 mm travel ????? impressive

    maybe the frame is not ready for that travel ...

    but this is the last of problems

  18. #18
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    but ... for me he must remove and put lower the high clamp , not the lower

    now there is a difference in steerer angle ....

  19. #19
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    Quote Originally Posted by eliflap View Post
    but ... for me he must remove and put lower the high clamp , not the lower

    now there is a difference in steerer angle ....
    You probaly noticed he's building a Scott Scale 29'er, when he moves the lower clamp he gets close to the a-c measurement this bike is made for (within a couple of mm's)

    But you can't do this on a cannondale, like you probably want to, except perhaps on the 29'er Scalpel if you remove that spacer you mentioned earlier.

  20. #20
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    I wouldn't feel safe on that lefty.....I hope he did not weld it while it's mounted....
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  21. #21
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    Quote Originally Posted by cdalemaniac View Post
    I wouldn't feel safe on that lefty.....I hope he did not weld it while it's mounted....
    No he did not weld it on the lefty, he found a metal rod with the exact same diameter as the lefty, and welded the clamp on that.

  22. #22
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    Quote Originally Posted by borgenvik View Post
    You probaly noticed he's building a Scott Scale 29'er, when he moves the lower clamp he gets close to the a-c measurement this bike is made for (within a couple of mm's).
    normally every 29er is made for 500 mm axle to crown, as already a Lefty is ...

    don't know if a Scale 29er frame is ok with 520-530 mm like i think it's now ...

    my opinion:

    29er HT are ok with 80-90 mm travel , more is not necessary

    and he has modified the steerer angle , who knows if in better or worse ( for me worse )

    and he has now a higher front height , maybe it's ok in Large frame but not ok in a Medium sized frame

    however , brave heart , i love this type of work indeed

    i noticed that the new position of the clamp is in a place where the fork diameter is a bit thinner ...

    how he refills the empty space ?

  23. #23
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    Quote Originally Posted by nathanbal View Post
    its an external bearing. supposedly they have chaged the upper bearing for the 29er scalpel so they can run the actual head tube shorter on the smaller sizes to allow for more standover height.

    im with eli on this. running huge negative rize stems to get the fit right is getting silly... if its technically feasible, cannondale should be making 29er specific lefty's to suit shorter hed tubes.
    Now I see..... Didn't have enough coffee that day I guess....
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  24. #24
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    Quote Originally Posted by eliflap View Post
    normally every 29er is made for 500 mm axle to crown, as already a Lefty is ...

    don't know if a Scale 29er frame is ok with 520-530 mm like i think it's now ...
    The a-c measurement is 49.8cm after he has moved the lower clamp up 20mm, it was 47,8cm before he cut the clamp off.

    I also feel that cannondale should should make atleast 3-4 different "clampdistances" on their forks, both for the small/medium 29ers but also for xl Flash/Scalpel. I dont think it is good for geometry in xl frames to have a 135mm headtube. I struggeld to find a comfortable position on my Cannondale Flash HM 26er in size xl, never felt i got dialed in. I have now sold that bike, and have bought a Cannondale Flash HM1 29er in size xl. On the 29er i feel very comfortable in all aspects of mtb riding.

  25. #25
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    Quote Originally Posted by borgenvik View Post
    The a-c measurement is 49.8cm after he has moved the lower clamp up 20mm, it was 47,8cm before he cut the clamp off.
    so his Lefty needs a bearing reset

  26. #26
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    i found a solution

    not a lefty , but very close to a Lefty

    its clamps are completely adjustable

    it fits so 26 and 29er frames , in many steerer tube sizes

    http://blackcatbonebikes.blogspot.com/

    i bought one of this rigid fork
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  27. #27
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    Has anyone seen a Lefty run with the stem UNDERNEATH the upper clamp?

    The bikes I'm currently looking at have VERY short head tubes; 90mm or so (Specialized SJ EVO R in size S, for example).

    Given a few mm up top for a very thin headset cover, that would leave me 40-45mm for a stem underneath the upper clamp.

    Looking for pictures or people that have done this before.

  28. #28
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    Quote Originally Posted by Le Duke View Post
    Has anyone seen a Lefty run with the stem UNDERNEATH the upper clamp?

    The bikes I'm currently looking at have VERY short head tubes; 90mm or so (Specialized SJ EVO R in size S, for example).

    Given a few mm up top for a very thin headset cover, that would leave me 40-45mm for a stem underneath the upper clamp.

    Looking for pictures or people that have done this before.
    it's a thing i already considered .

    but :

    - you need a very short tube in the frame , maybe 90mm can be too long.

    - maybe you need an XL lefty

    - and how you keep firmly the Lefty ? the stem has the function to keep close the steerer tube , the upper clamp, the bearing seal ... all the front part of the bike

  29. #29
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    Quote Originally Posted by eliflap View Post
    it's a thing i already considered .

    but :

    - you need a very short tube in the frame , maybe 90mm can be too long.

    - maybe you need an XL lefty

    - and how you keep firmly the Lefty ? the stem has the function to keep close the steerer tube , the upper clamp, the bearing seal ... all the front part of the bike
    I'm not sure I understand the last part. Just like everyone else with traditional forks, who throw in spacers on top of, or below their stem, I'd use a combination of thin and thick spacers to take up the space between the top of the headset and lower face of the upper clamp on a lefty. Except, in this case, the stem would serve as ~40mm (most stems have around 40mm in stack height) of spacers between the clamps.

    Lefty clamps: 137.5mm.
    Specialized SJ Evo R Headtube: 90mm
    Easton EA90 stem: 40mm stack height

    So, I'd have 7.5mm of room to take up with additional steerer spacers. If I couldn't find a spacer to take up a 0.5mm gap or so, I'd take an aluminum spacer (10mm or so), and then use a facing tool on it to take it down to the required height. They're cheap, so with a bit of trial and error, I could get a perfect fit.

  30. #30
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    maybe my poor english ...

    the spacing you wrote can be correct . but look at safety point:

    1st case , a normal Cannondale frame .

    try to think about the lefty steerer tune assemply

    lefty + tube + stem and the frame

    the tube is slided from bottom to top into the frame .

    the 2 lefty clamps are locked to 9 Nm with 6mm bolts to the tube

    ( do not consider the bearing cover , not important to the problem )

    the stem is on the upper clamp , tighten at 5 Nm

    ... and this stem holds the tube and the 2 clamps all togheter

    2nd case, another frame :

    try now to imagine the stem undeneath the upper clamp.

    the tube is slided and it keeps the lower clamp , frame , stem , upper clamp

    is this assemply safe as the previous ?

    the forces on the zone are all under control or is there a point-break ?

  31. #31
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    Quote Originally Posted by eliflap View Post
    maybe my poor english ...

    the spacing you wrote can be correct . but look at safety point:

    1st case , a normal Cannondale frame .

    try to think about the lefty steerer tune assemply

    lefty + tube + stem and the frame

    the tube is slided from bottom to top into the frame .

    the 2 lefty clamps are locked to 9 Nm with 6mm bolts to the tube

    ( do not consider the bearing cover , not important to the problem )

    the stem is on the upper clamp , tighten at 5 Nm

    ... and this stem holds the tube and the 2 clamps all togheter

    2nd case, another frame :

    try now to imagine the stem undeneath the upper clamp.

    the tube is slided and it keeps the lower clamp , frame , stem , upper clamp

    is this assemply safe as the previous ?

    the forces on the zone are all under control or is there a point-break ?
    When using a Project 321 steerer (for any non-Cannondale headtube; tapered in this case) you'd use spacers between the headset cover and the upper clamp of a Lefty. In most cases, the gap would be 20-30mm, depending on the length of the headtube in question. In the M, L and XL sizes, I'd have a 100, 115, and 130mm headtube. Obviously, with those, I'd use spacers to fill in the gap. The stem would go on top of the clamp.

    In the scenario I'm describing, the stem takes the place of the spacers. The clamps still contact the steerer tube in the same place, with the same amount of material (137.5mm of spacers, headtube, and headset) between them. The stem would, in theory, exert less leverage on the steerer and head tube, because the effective lever length is shorter.

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