Ken Bessler asked:

How do I adjust the seat height?

Art Harris replied.

There are a couple of methods to get you in the ball park:

1) Center of BB to top of saddle = 0.883 x inseam.

2) Pedal axis (pedal down, aligned with seat tube) to top of saddle = 1.09 x
inseam.

These numerical "systems" are pure snake oil.

The first doesn't even take crank length into account!

Neither of them regards foot length or foot position on the pedal.

They also presume that it is possible to make a meaningful measurement
to an unspecified type of saddle to three significant digits, which is
pretty meaningless, given the range of shapes and flexibilities of saddles.

3) Raise saddle in 1/8" increments until your hips just start rocking when
you pedal, then lower it until you stop rocking.

That's the best way.

See also: http://sheldonbrown.com/saddles.html

You also want to set the fore/aft position of the saddle properly. A good
starting place is to have the front of your knee directly over the pedal
axis with the pedals horizontal (3 o'clock position). Have someone help you
using a plumb line.

See: http://www.sbraweb.org/setup.htm

See also http://sheldonbrown.com/kops.html

Also, how do I measure the frame size? Is it from crank
centerline to top tube centerline (at the seat post)? I got
exactly 50cm this way


Unfortunately, there is no established standard. There are at least three
ways of specifying frame size:

1) Center of BB to center of top tube
2) Center of BB to top of top tube
3) Center of BB to top of seat tube
(all measured along the seat tube.)

More than that, actually! Some sloping-top-tube frames are measured by
where the seat tube would end up if the top tube didn't slope down from
the head tube!

Take your pick. I prefer #1.

I prefer #3, but to me the top tube length is the much more important
dimension, see: http://sheldonbrown.com/frame-sizing.html.

Sheldon "Traial And Error" Brown
+--------------------------------------------------------------------+
| We engaged in innumerable discussions, and often after an hour |
| or so of heated argument, we would discover that we were as far |
| from agreement as when we started, but that both had changed to |
| the other's original position in the discussion.--Orville Wright |
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Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
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