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  1. #1
    Senior Member
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    BB drop and BB height

    I'm a little...ok...A LOT confused about this. Are they one in the same? Whats the preferred measurement when track-frame shopping and why is it very important to a track bike's design and function? I think I understand the outside pedal clearance issue on a steeply banked track when slowing and moving up-track, but there's gotta be more to it than this, yes? Am I on the right track with this? (HA!...as my Filipino friends would say, "Ahhhh...you'rrre habing pun wit a pun! )

    But seriously....
    May the road be long with the wind on your back.

  2. #2
    Disgruntled Grad Student seejohnbike's Avatar
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    nope, not more to it. that's pretty much it.

    BB drop and BB height are not the same, more of a yin and yang type thing. BB drop is the distance from a level plane between both axels, and the BB. BB height is the vertical distance from BB to ground.
    If we knew what we were doing, it wouldn't be called research.

  3. #3
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    What would be a proper bb drop and bb height measurement on a legal track bike? I've seen fg bikes that are trackbike-like in appearance and are probably perfectly suitable for roadwork, but I'm going to guess there'd be some pedal-strike issues on the banks of a track if the measurements are more road than track.

    Is there an acceptable range for this measurement?...or is there only ONE bb height/drop measurement for legal trackbikes that is required?
    May the road be long with the wind on your back.

  4. #4
    Senior Member
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    Classic frames like the old Cinelli's and most NJS frames are right around 60 mm, while newer bikes, especially sprint bikes designed for 250m tracks with 45˚ banking are 50 mm or less. For comparison, most road frames are 68-70 mm I think.

  5. #5
    Senior Member chas58's Avatar
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    That is about right. 60mm drop is the most you would want with a track bike with 165mm cranks if you are on a nicely banked track. 50-60mm drop would be fine.

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