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  1. #1
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    One bike has a longer top tube than the other, but has a shorter reach. How?

    The Banshee Spitfire has a TT of 23.2 and a reach of 427 cm
    The Devinci Troy has a TT of 23.8 and a reach of 421 cm.

    How? I figured that a longer TT would have a longer reach measurement.

    What am I missing?

  2. #2
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    I'm not looking at the numbers but if you think about the front triangle, as the seat tube gets slacker the ETT increases and the BB moves forward. At least this is how I understand it.
    What does the ego chart state as the STA?

  3. #3
    Bicyclochondriac.
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    Like mnigro said, the seat tube angle might account for it.

    If two bikes have the same ETT, but one has a slacker seat tube angle, that one will have a shorter reach.

    This is why reach is a much more useful measurement than ETT, IMO.
    15mm is a second-best solution to a problem that was already solved.

  4. #4
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    Quote Originally Posted by kapusta View Post
    Like mnigro said, the seat tube angle might account for it.

    If two bikes have the same ETT, but one has a slacker seat tube angle, that one will have a shorter reach.

    This is why reach is a much more useful measurement than ETT, IMO.
    imo, ETT is more important for fitting because it accounts for seat tube angle, reach doesnt

    no one sits right above (vertically i mean) the bottom bracket

    tho, i guess reach is important for fit when standing up and riding
    2010 GT Avalanche Expert

  5. #5
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    The reason reach is more important is that seat tube angle is not a fixed measurement. You can slide the saddle fore/aft and change the effective STA. When you fit a bike, you place the saddle a certain distance back from the BB. With a steeper STA, you will put the farther back on the rails. Slacker STA, you will slide the saddle forwards.

    So, the effective seat tube angle can be changed. The BB position can't.
    15mm is a second-best solution to a problem that was already solved.

  6. #6
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    true
    2010 GT Avalanche Expert

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