Hub Center to Flange Center???

Discussion in 'Cycling Equipment' started by !Jones, Aug 25, 2007.

  1. !Jones

    !Jones Guest

    I'm playing with a spoke calculator. Why do we need "Hub Center to
    Flange Center"? What does it give me that I use in the wheel? If the
    wheel is symmetric, then what difference does it make?

    I'm looking at http://www.bikeschool.com/spokes/index.cgi

    I also note that the distance between the flanges isn't an input. Can
    I calculate the width of the wheel (meaning the flanges) from that?

    I don't think I'm measuring it right.

    Jones
     
    Tags:


  2. JeffWills

    JeffWills Guest

    On Aug 25, 9:58 am, !Jones <p...@off.com> wrote:
    > I'm playing with a spoke calculator. Why do we need "Hub Center to
    > Flange Center"? What does it give me that I use in the wheel? If the
    > wheel is symmetric, then what difference does it make?
    >
    > I'm looking athttp://www.bikeschool.com/spokes/index.cgi
    >
    > I also note that the distance between the flanges isn't an input. Can
    > I calculate the width of the wheel (meaning the flanges) from that?
    >
    > I don't think I'm measuring it right.
    >
    > Jones


    Trigonometry, my dear boy. The distance from hub center to the flange
    gives you the base of the triangle where the vertical distance from
    the hub to the rim is the height and the spoke forms the hypotenuse.
    Without knowing this measurement, you can't correctly determine the
    spoke length.

    Many hubs (most rear and some front) are not symmetrical right-to-
    left. You need to determine the distance from center to flange on each
    side to get the lengths exactly right. It can make a difference-
    highly dished rear wheels can have a difference of 2mm from left to
    right.

    Try using Spocalc: http://sheldonbrown.com/rinard/spocalc.htm . The
    spreadsheet includes data on many common rims and hubs, and allows
    independant data entry for items not included. It's never let me down.

    Jeff
     
  3. !Jones

    !Jones Guest

    On Sat, 25 Aug 2007 11:19:51 -0700, in rec.bicycles.tech JeffWills
    <jwills@pacifier.com> wrote:

    >Trigonometry, my dear boy. The distance from hub center to the flange
    >gives you the base of the triangle where the vertical distance from
    >the hub to the rim is the height and the spoke forms the hypotenuse.
    >Without knowing this measurement, you can't correctly determine the
    >spoke length.
    >
    >Many hubs (most rear and some front) are not symmetrical right-to-
    >left. You need to determine the distance from center to flange on each
    >side to get the lengths exactly right. It can make a difference-
    >highly dished rear wheels can have a difference of 2mm from left to
    >right.
    >
    >Try using Spocalc: http://sheldonbrown.com/rinard/spocalc.htm . The
    >spreadsheet includes data on many common rims and hubs, and allows
    >independant data entry for items not included. It's never let me down.
    >
    >Jeff


    Ya know, my dear boy, what we need are four points:

    >Trigonometry, my dear boy. The distance from hub center to the flange
    >gives you the base of the triangle...


    A distance alone does not give you the base of a triangle... if you
    knew trig, dear boy, then you'd already know that; if all you have is
    distance, you're not in Euclidean space yet, so it's nonsensical to
    start talking about triangles until you unequivocally fix three
    noncolinear points. (Actually, I think you're fixing two and taking a
    perpendicular delta, but that's not what you wrote.)

    Useless post. Go back and review your undergraduate trig and don't
    address me as "my dear boy" until you're sure that you know your
    subject... I'm pretty well up to date on my trig... "dear boy".

    Jones
     
  4. !Jones

    !Jones Guest

    On Sat, 25 Aug 2007 13:31:13 -0700, in someplace JeffWills
    <jwills@pacifier.com> wrote:

    >OK- *you* explain to *me* how you're going to calculate spoke length
    >without knowing how far the flange is from the center of the hub.


    That's what I was asking. Is that what it is? Would zero mean that
    you only had one flange? (That would be an unstable wheel, naught?)
    Would 0.5" mean that the centers were an inch apart?

    Jones
     
  5. Gary Young

    Gary Young Guest

    On Sat, 25 Aug 2007 12:58:08 -0500, !Jones wrote:

    > I'm playing with a spoke calculator. Why do we need "Hub Center to
    > Flange Center"? What does it give me that I use in the wheel? If the
    > wheel is symmetric, then what difference does it make?
    >
    > I'm looking at http://www.bikeschool.com/spokes/index.cgi
    >
    > I also note that the distance between the flanges isn't an input.


    It is, in a sense. Lefthand Hub-Center-to-Flange-Center distance +
    righthand Hub-Center-to-Flange-Center distance = distance between flanges.
    What may be confusing you is that this particularly calculator only does
    one side of a wheel at a time.

    > Can
    > I calculate the width of the wheel (meaning the flanges) from that?
    >
    > I don't think I'm measuring it right.
    >
    > Jones


    This page has a diagram:

    http://www.damonrinard.com/spocalc.htm

    Scroll down to "How to Measure Hub and Rim Dimensions."

    "Hub Center to Flange Center" is the same thing as WL and WR on the
    diagram. (That's W-subscript-L, W-subscript-R.)
     
  6. !Jones

    !Jones Guest

    On Sat, 25 Aug 2007 15:40:57 -0500, in rec.bicycles.tech Gary Young
    <garyyoung3@gmail.com> wrote:

    >It is, in a sense. Lefthand Hub-Center-to-Flange-Center distance +
    >righthand Hub-Center-to-Flange-Center distance = distance between flanges.
    >What may be confusing you is that this particularly calculator only does
    >one side of a wheel at a time.


    Oh... well, that's a "light bulb moment"!

    Got it!

    Thanx!

    Jones
     
  7. JeffWills

    JeffWills Guest

    On Aug 25, 1:24 pm, !Jones <p...@off.com> wrote:
    > On Sat, 25 Aug 2007 15:40:57 -0500, in rec.bicycles.tech Gary Young
    >
    > <garyyou...@gmail.com> wrote:
    > >What may be confusing you is that this particularly calculator only does
    > >one side of a wheel at a time.

    >
    > Oh... well, that's a "light bulb moment"!
    >


    Ah-ha! My own light bulb moment: you were using a crappy spoke
    calculator. Spocalc is so much nicer. I will now retire to my couch
    and cats.

    Jeff
     
  8. On Aug 25, 11:58 am, !Jones <p...@off.com> wrote:
    > I'm playing with a spoke calculator. Why do we need "Hub Center to
    > Flange Center"? What does it give me that I use in the wheel? If the
    > wheel is symmetric, then what difference does it make?
    >
    > I'm looking athttp://www.bikeschool.com/spokes/index.cgi
    >
    > I also note that the distance between the flanges isn't an input. Can
    > I calculate the width of the wheel (meaning the flanges) from that?
    >
    > I don't think I'm measuring it right.
    >
    > Jones


    When measuring hub dimensions you need 2..flange diameter..center hole
    to center hole across the hub flange and center of the hub to flange
    dimension on each side and yes, if the hub is symmetric, the spoke
    lengths will be the same on each side.
     
Loading...
Loading...