Stem angles please clarify

carl_p
carl_p Posts: 989
edited June 2013 in Road buying advice
I'm considering a new stem that is stated to be 86 degrees. Would this be the same as +/- 4 degrees?

My head tube angle is 72.5 degrees so does this mean the stem would slope downwards by 13.5 degrees, i.e 86 - 72.5 when viewed from the side?

I suspect not but can't get my head around it at the moment, so any clarication would be appreciated :|
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Comments

  • jgsi
    jgsi Posts: 5,062
    You can get stems in varying angles to suit.
    You need to suss out what is best for you.
    eg Caad10 headtube angle 73 degrees.
    I like my stem to be horizontal.
    Use a 3t stem with a 17 degree angle to compensate.
    Stem is thus level.
  • mfin
    mfin Posts: 6,729
    It will slope up. To be 'parallel to the ground' it would be a -17.5 stem because 72.5+17.5 = 90 degrees.

    +/- 4 is a little unusual, most are +/-6 degrees, so a +/-4 will slope up a tiny bit more than a regular stem.

    +/- 6 is what you see on most bikes in photos when a stem isn't parallel to the ground as these are the most common stems, people usually go for a -17 when they want to 'get lower'

    Of course, 'Mary Poppins riders' even flip the stems over to get the Mary Poppin's Position and then the Stem is nowhere near parallel to the ground as instead of counteracting the head tube angle it sort of does the opposite.

    EDIT. Someone else beat me to it by the time I typed it.
  • carl_p
    carl_p Posts: 989
    Thanks all. I believe my current stem is +/- 6 so will think how it will look compared to that.

    There's no possibility whatsoever of the stem being flipped :D
    Specialized Venge S Works
    Cannondale Synapse
    Enigma Etape
    Genesis Flyer Single Speed


    Turn the corner, rub my eyes and hope the world will last...
  • markhewitt1978
    markhewitt1978 Posts: 7,614
    Carl_P wrote:
    I'm considering a new stem that is stated to be 86 degrees. Would this be the same as +/- 4 degrees?

    My head tube angle is 72.5 degrees so does this mean the stem would slope downwards by 13.5 degrees, i.e 86 - 72.5 when viewed from the side?

    I suspect not but can't get my head around it at the moment, so any clarication would be appreciated :|

    Strange for a stem to be 86 degrees? That's almost vertical? I have stems which are 7deg, for a shallow rise and 17deg for a much steeper rise. I've seen them up to 45deg but that's a lot.

    Anyway for comparing stems you need this http://alex.phred.org/stemchart/

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