Before Tuesday’s ride I made some adjustments on the bike.  The first was raising the stem about 10 mm.  I had two spacers above the stem and decided the bars needed to be just a bit higher than the seat.  I also moved the seat back about 10 mm and tried to find a more comfortable tilt.  I had this tendency to slide forward on the seat.  This was causing some knee and back pain, as well as, I suspect, some loss of power.

Stem worked out ok.  Amazing what a few millimeters will do.

The seat had other ideas.  I didn’t torque the bolt properly and about 1.5 hours into the ride the seat came lose.  I had to stop and make adjustments on the road.  Just by accident I found a very comfortable position for the seat.  Didn’t measure, just happened on the right tilt and position.  The rest of the ride I wasn’t sliding forward and was very comfortable on the climbs. I also found that my sit bones were in the right position on the seat.  I’m going to mark these positions, probably by etching the seat rails so I have a reference mark.

Serendipity.