Originally Posted by
rpenmanparker
Can't be done. Oh you can measure from the BB over the top of the saddle and back down to the other side of the BB. That will get you two saddles at the same height. But what about saddle compression? When you get on the two different saddles, the two won't compress the same. Trial and error is the only answer beyond the ball park that the measurement provides.
Mostly.
You can get close though.
Put a straight edge or ruler over the part of the saddle where you actually sit and measure to the BB center from that edge using a tape measure.
Now put on the new saddle, level it out, then put the ruler over where you will be sitting on the new saddle and match the measurement as best as you can.