Wide saddles tend to hinder circulation and movement, causing hip pain. Narrow saddles also cause pain that restrict the distance of cycling.
The traditional way to measure the sit bones measurement was to place a pie shell between two pieces of thin paper (or wax paper) on a flat surface. Sitting on this causes two dents to appear on the surface and this is your saddle size.
The traditional material for a bicycle saddle is leather and the Brookes saddle is still quite popular.
- Bicycle Seats Explained - An article by Jim Langley