I'll answer your question throughly a little later this evening. I'm desperate to finish two Moon frames and a ton of other stuff so I need to focus for a while today to make some progress.
I didn't state a preferance for a front center either way because it is a "resulting" dimention based on other dimentions that are directly related to rider position and weight distribution, frame fit, or steering charactistics. There are a multitude of ways to arrive at a FC of 58.9. Which way would you prefer to get there? Each dimention you choose will have an effect on the aspects of the frame I just mentioned. One way of meeting that dimention might not be to your liking or result in a charactistic that is not what you wanted in the bike. What if the bike has a 58.8 FC or a 59.0 FC? How important would either way be? I'm sure I could build a bike with a FC of 58.9 that you would not like. Furthermore, someone else that rides the same size frame but needs a different fit to accomodate them should not be put into the same FC because what works for him will not work for you and vice versa. I think you get where I'm heading, but I'll lay it all out later on. In the meantime I will also sort through some of my drawings and see what sort of FC's I come up with so we can relate to each other. FC is a different language than what I normally speak.
Brian Baylis La Mesa, CA
> Hi Brian,
> You don't really say much at all about the "front center" in your
> description, or state anything about a preference for short or long
> centers, wanna clarify?
> Grant 51cm McLean
> 58.9 is my magic front center number, formula or not...
> Brian Baylis wrote:
> I begin with the seat angle. Once I have established that I determine
> the top tube length/stem length combination. The actual frame size can
> vary a lot more than most people are willing to accept from my
> experience. Frame size has to do partially with position on the bike
> relative to several other factors in the design. As a custom builder, I
> don't just build racing style bikes. Bikes for different purposes can be
> different sizes for the same rider, but I find most people are too rigid
> in their belief of what "frame size" they take. The rest of the frame
> design isn't related to the ride as much, but have to do with weight
> distribution, fit, steering qualities, how the bike handles the gearing,
> etc., etc.. It's not rocket science really, but knowledge and common
> sense are very important. Otherwise you have to rely on formulas and
> whatnot. (There's that word again, what the hell is "whatnot" anyway?) I
> determine each of these dimentions based on the conditions the bike will
> face, the components, and whatever special needs the rider requires.
> The resulting small frame designed this way is comfortable, steers
> beautifully, and rides and fits the rider the way it should (end of snip)