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  1. #1
    3rd Grade Dropout Erzulis Boat's Avatar
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    Oct 2005
    Santa Barbara Calif.
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    "Oversized" steel tubesets

    I am probably going to make my next frameset (track geometry) with the OS Columbus (Nova) or some True Temper from HJ. Lugged construction.

    I have not ridden any OS bikes, so what am I going to lose/gain here?

    Are the rides "stiffer" due to increases TT/BT diameter, or do they kind of even it out with wall thickness so the ride is closer the "Standard" tubesets? By looking at the specs it seems that you gain stiffness, but still incur a weight penalty even if the walls are a tenth less, due to the greater diameter.

    I would tend to think that this was done for cosmetics, but any advice on how to exploit the OS tubesets traits?

  2. #2
    Senior Member Nessism's Avatar
    Join Date
    Jun 2004
    Torrance, CA
    My Bikes
    Homebuilt steel
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    STD tube frames, 1” top tube and 1.125” seat and down tube, are rare these days. One could go so far as to say that Oversize (OS) is the new standard – and has been for the last 15 years or so. There are lugs available for Super OS diameters as well these days: 1.25” top and seat tubes, and 1.375” down tube. Lots of choices.

    In terms of stiffness/weight; as the tubes get larger, and thinner, the stiffness can remain constant while weight is reduced. For example, an OS frame with similar stiffness to a STD frame will weigh about - 1/3 lb. lighter. The key is to pick a tubeset to match the ride qualities you want. A couple of good ones for general purpose riding are Columbus Zona and Dedacciai COM12.5 (ZeroUno). Both will build into a lighter frame than the typical Columbus SL frame, while being slightly stiffer as well. One drawback to thin walled tubes needs to be considered: they dent more easily than thicker tubes. The thin tubes are made from stronger alloys, so the metal alloy is more dent resistant, but this does not fully make up for the fact that the tubes are thinner, thus they dent easier.

    My own personal bikes (two of them) use Super OS tubes. I really like these bikes since they are stiffer than a similar weight OS frame. I’m not super strong, or heavy, but I hate chain rub so stiffness is important to me.

    Hope this helps.
    Last edited by Nessism; 10-10-08 at 08:55 PM.
    Becareful buying/selling bike parts on-line. I learned the hard way. :(

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