Hi Etincelle,

I had my sit bones measured in two ways.
My lbs is a specialised dealer, so I sat on their measuring device, which is basically like a piece of foam that indents were your sit bones are.

I also followed this up at home using information posted by Lorri Lee Lown, a USAexpert cycling coach on another womens discussion board.
She says "for a bike fit you'd be wearing cycling shorts. If you lay on your back with your knees bent and feet on the ground, you can find the sits bones (ischeal tuberosities for you science types), by compressing the soft
tissue on the butt (buttocks for you science types). This can be a challenge with folks who have more soft tissue or very defined hamstring muscles). Once you find the bones, you measure the distance from one to the other. The crown of the saddle (the highest, flat part before it dips down on the sides) should be at least as wide as the measurement of the sits bones, but not wider than 1 or 2 cm more."

I had my husband measure the distance for me, as I think it would be too difficult to measure all by yourself

Hope this helps,

Alison