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  1. #1
    Senior Member ph4nt0mf1ng3rs's Avatar
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    Frame Sizing Questions

    Hello Frame Builders.

    Discalimer: At first I considered posting this on the SSFG or Track threads, but since it has to specifically do with frames, why not post it on the Framebuilders thread. FIRST TIME IVE DONE THIS, SO PLEASE DONT LAUGH AND PLEASE BEAR WITH ME THROUGH MY LEARNING OF FRAMES ETC.


    Now my inseam is 32" and I was considering purchasing a track frame, which is exactly what I did.
    I am 5' 10" and purchased a 54cm frame. However, I feel very stretched out when I ride the hoods (I had it as a Singlespeed for a while, and threw road bike brakes onto the drops).

    I considered buying a shorter stem, becasue I want to throw on aero bars for Time Trialing etc. However, what Ive noticed are the following things when I considered purchasing a frame with steeper geometry.

    1. When comparing my Windsor Hour frame gemoetry to other frames that I considered buying, even when sizing down to a smaller frame size with steeper geometry, the measurements came down to fractions of centimeters difference. ULtimately, the question here is, is there a significant difference in how a 530mm top tube affects the reach of the rider over a 550mm top tube?

    More specifically, the two different (even more actually) frames I looked at that had steeper gemoetry than teh bike I have now. Does aggressiveness refer to the position of the rider, or to the responsiveness of the bicycle?

    2. If I want to acheive a more compact riding position, say like a road time trialist or a track time trialist, should I go for my frame size in a steeper S/T angle (atm im riding 73 degrees- considering moving up to 75.5), or would a smaller frame size (say going from 54 to 51) and keeping the same lax geometry afford me a more compact riding position, or should I go a smaller frame size smaller and go for steeper gemoetry?

    3. Does top tube length ultimately determine how far I reach/compactness? I know I can shorten my stem, but I expect that even shortening my stem will have me considerably stretched out in my current setup (even using the plumb bob method to determine my front-to-back saddle position, with my seat moved forward to the max, im still not forward enough for my knee does not allow the bob to bisect the center of the pedal...)

    again excuse my ignorance, but Im still learning just like any new person.

    Thanks in advance frame builders.

    Again, my goal is to acheive a more compact positioning than I currently have. idk if you guys want pics lol. thanks again!
    Quote Originally Posted by Vixtor View Post
    Seriously, I wouldn't trust it at all.

    phatomfingers would be interested in this.

  2. #2
    Randomhead
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    since you can adjust setback (seat post) and reach (stem) on any frame, the frame really determines the weight balance. Time triallists and track riders tend to have more forward positions. Thus you would want a steeper seat tube angle. 20mm difference in top tube is certainly significant. If you get a shorter stem, you're moving your weight back and changing the way the steering feels.

    Knee over pedal (KOP) is somewhat discredited. I don't know where my knee falls relative to my pedal

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