For cyclist - is inseam and pubic bone height the same thing?

Here is a tool via which you can use your inseam measurement to find out the best-sized bike for you:

http://www.totalbike.com/service/frame_size.php

Inseam [of your pants] is shorter than pubic bone height.
Here is the Rivendell Bicycle Works method of measuring pubic bone height.
“a. Stand in bare feet on a hard floor.
b. Put your feet 10 inches apart.
c. Hook the edge of a metal metric tape over a thin edge—two rulers, or a thin hardcover book.
d. Pull the tape up hard against your pubic bone. We tell folks, “Try to lift yourself off the ground
e. Have a friend take reading as you do this.
Do this twice, thrice, or a hundred times. As long as the tape is straight and the guy reading the number knows how to read a tape, you should record the highest of all the readings you get. Why not the average? Because you’ll never pull past the bone, so you can’t get a reading that’s too high.”

http://www.rivbike.com/article/bike_fit/pbh_and_how_to_measure_it

I’ve read that page, and I understand everything but where the ends of the tape go. I understand that it’s from the floor beneath your center to your pubic bone, but I don’t know what part of the pubic bone we’re supposed to measure to, and I really don’t know what they mean by “try to lift yourself off the ground.” That seems to imply that the measuring tape is strung up under the crotch in some way, which the directions don’t otherwise imply. Could someone help me please?

kathairon: Imagine a pole 6 ft long. You straddle it like you are riding a horse. Two friends pick it up until your feet are almost leaving the ground. Measure from the ground to the upper edge of the pole.

Is that more clear?

The measuring tape and two rulers is kind of hard to picture now that you point it out.