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  1. #1
    Fat Guy in Bike Shorts! manual_overide's Avatar
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    Top Tube: sloping vs. horizontal

    What are the differences between the two? I'm looking at a C'dale Bad Boy and the Bad Boy Ultra. The Ultra has a sloping top tube frame and regular has a horizontal top tube. I happen to like the horizontal style better, so other than that, I really want the Ultra. Does a slope have an advantage over a horizontal tube somewhere? Or are they just for cosmetic purposes? I suppose it would give me more clearance if I slid off the front of the saddle, which I have never done and can't really forsee a situation where that would ever happen. Possibly it accomodates the longer fork you have with a front suspension?

  2. #2
    cab horn
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    Only girly mans ride sloping.

  3. #3
    hello roadfix's Avatar
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    Frame size also determines whether horizontal or sloping. If you're short you have no choice but to fit on a smallish frame with a sloping top tube.
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  4. #4
    vegan powered
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    Mine is sloped. I dont feel any more girlyish.

  5. #5
    Advertise here! Chuvak's Avatar
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    so is mine, but then again my frame has compact geometry

  6. #6
    DEK
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    One reason some companies are going to sloping top tubes is to reduce the number of frame sizes needed. I was looking at a Giant OCR 1 and it wasn't measured in CMs but rather as S, M, L and XL. So, they only needed 4 frames sizes instead of 6, 7 or more. Saves on production costs.

  7. #7
    la vache fantôme phantomcow2's Avatar
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    I have a 21" frame, it has a horizantal top tube. I love it.

  8. #8
    By-Tor...or the Snow Dog? hi565's Avatar
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    Quote Originally Posted by CrimsonEclipse
    A real man rides whatever he wants.

    CE

    Amen Bro!

    Quote Originally Posted by DEK
    One reason some companies are going to sloping top tubes is to reduce the number of frame sizes needed. I was looking at a Giant OCR 1 and it wasn't measured in CMs but rather as S, M, L and XL. So, they only needed 4 frames sizes instead of 6, 7 or more. Saves on production costs.
    I thought that it was sloped because it was for comfort, or is it that the seats are so high that it basically becomes like a regular road bike?
    ----------------------------------------------------------

  9. #9
    I couldn't car less. jeff williams's Avatar
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    Lower center of gravity, frame is less flexy sideways in sloped toptube.

    A horizontal toptube is a bike you run saddle level or higher with bars. Areo position.
    Incline optubes can be run high, level or low, but least likely saddle higher than the bars.
    The body position can be more upright.

    Incline tube are front end control geometry,
    Horizontal are designed with a straighter seattube and more concernred with stroke to the bb and exact reach top tube length.

    Well that's what I think...

    And then those crazy persuit bikes with the top tube going down towards the front???

    Flatland more horizontal tube, speed bike.
    Offroad, incline control geometry.

  10. #10
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    The difference between a sloping top tube and a horizontal one is that the top tube attaches to a different place. It does not affect your saddle position. It does not alter your centre of gravity, the bottom bracket height does that.
    It may affect the position of threaded eyelets on your seat tubes for attatching a rack. If you have to bend the rack stays down to meet the eyelets, you reduce the triangulation of the rack mounting, and hence its stiffness.
    The lowest height of the handlebars may be limitted by the head tube length. In smaller frames, the head tube is often quite high. This is not neccessarily a bad thing.
    Compact or horizontal, you should select the appropriate length for your size and riding style.

  11. #11
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    Quote Originally Posted by operator
    Only girly mans ride sloping.
    True. A real man (i.e. proper gentleman) rides a full step through frame so he does not have to lift a leg way up like a dog at a fire hydrant.

    Paul

  12. #12
    I couldn't car less. jeff williams's Avatar
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    Quote Originally Posted by MichaelW
    The difference between a sloping top tube and a horizontal one is that the top tube attaches to a different place. It does not affect your saddle position. It does not alter your centre of gravity, the bottom bracket height does that.
    .
    The bikes ballance not the riders, I ride a mtb and move the bike from side to side under me.
    If you notice, mtn-biking, the rider stays mostly upright, the bike moves under (standing on the pedals).
    A horizontal toptobe will have a heavier upper weight, it will be harder to move the rear around.

    It's not much, but try endo's or hopping the rear around to line up on a tight switchback and it's noticable.

    I'm lucky my bike has an incline, but not as dramatic as most ATB's, I can still streach out areo for XC.

    3? -points of ballance =the bikes, your bodies centre and the interaction of the 2 =resulting shift.

    The center of gravity can be altered by justing the seat hight or getting off the saddle.
    Last edited by jeff williams; 02-04-05 at 01:54 PM.

  13. #13
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    Quote Originally Posted by The Fixer
    Frame size also determines whether horizontal or sloping. If you're short you have no choice but to fit on a smallish frame with a sloping top tube.
    The word "short" might be a bit vague. The horizontal top tube was "standard" on road bikes from around 1890 to around 1995. During that century, millions of people who are 5'2" or 5'3" were out enjoying their road bikes. Frame builders could design frames for THAT rider, or someone a foot taller. A UK company that still designs road bikes "the old fashioned way" offers one of its models in ten sizes and each size comes with a choice of three top tube lengths.

    "Stand over clearance"? This was important stuff during the 1924 Olympics, when cyclists were required to stand with both feet flat on the ground, and push their bikes toward the finish line. After 1924, cyclists adopted the practice of sitting on the saddle while riding, and there was no longer any need to put both feet flat on the ground during a competition. (NOTE: not all attempts at humor are based upon actual facts.)

    When production of "mass market" frames moved to communist China, bike companies tried to come up with "one size" fits all designs for bike frames. The result is that it is now much more difficult for someone who is about 5'2" tall to get a good fit on a road bike.
    Last edited by alanbikehouston; 02-02-05 at 12:11 PM.

  14. #14
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    I would LOVE to be a girly man,
    just like super Mario

  15. #15
    hello roadfix's Avatar
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    Quote Originally Posted by alanbikehouston
    The word "short" might be a bit vague. The horizontal top tube was "standard" on road bikes from around 1890 to around 1995. During that century, millions of people who are 5'2" or 5'3" were out enjoying their road bikes.
    Quite true, but a 5'2" person on a horizontal top tubed, 27" wheeled bike virtually had no standover clearance.
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