This is an odd one - so have patience.
If I measure my sit bones when lieing down,knees bent they measure 115mm. I then tried flattening playdough onto a flat surface and then covered this with paper before sitting on the paper. Outside to outside of the marks measured 144 mm. Does any of this sound right? What do the Saddle experts think I need, width wise, in a saddle? To me 115mm seems very narrow & 144mm seems very wide.

but I think you're wasting your time. Comparing advertised saddle widths to a sit bone width is pretty meaningless, since the width of saddle might be the same but the curvature from side to side may be entirely different. It's the shape that's usually the most important feature.

I finally figured out that most saddles are not round enough for me in the sit bone area. The Fizik Gobi has been a blessing.

try this one...

http://www.nidus-corp.com/TinyImages/LargeImages/assometer.jpg

try this one...

http://www.nidus-corp.com/TinyImages/LargeImages/assometer.jpgI feel kind of dirty looking at that.
:eek:

C- 40 thanks & agree shape is V.Important - along with the Width ( has to be a better way to say that ! ) I know the shape I need (flat)

Dirtboy - Bang on the money - that diagram explains it perfectly - thanks.

Scotty2Hotty - you need help !

Scotty2Hotty - you need help !

This is not news to forum regulars :)

Your sit-bones will widen (spread out) when you're in an upright, riding position such as on the hoods or tops of a bar. When you bend over and are in an aero position, your sit-bones will become narrower.

Your sit-bones will widen (spread out) when you're in an upright, riding position such as on the hoods or tops of a bar. When you bend over and are in an aero position, your sit-bones will become narrower.

How'd you get that idea? It's all one big bone -- there's no movement of the sit bones relative to each other, unless your hip is broken.

It may be true that being hunched over works better with a narrower saddle, but it has nothing to do with your sit bones moving relative to each other.

there's no movement of the sit bones relative to each other, unless your hip is broken.

True. But perhaps wzq622 was thinking about the saddle-to-pelvis contact points coming closer together as your lean angle increases and you rotate your hips forward and down.

Riders sitting upright on the rear portion of a wide saddle will have their ischial tuberosities (lowest points on the ischium, misleadingly called "sit bones") in contact with the saddle. As riders lean forward and rotate their hips to get a flat back, the saddle-to-pelvis contact points move into the pubic arch and closer together as shown on the illustration. The red line represents the saddle cross-section at rear, center, and tip.