Sorry if this is redundant with some of the other good explanationsQ


Let's see if I can explain these differences across the board - I hope to help you with a perspective. Other perspectives are possible, of course!

The most important criterion for saddle height is how far you extend your leg to the bottom of the pedal stroke when pedaling. One of the old-fashioned tests was to wear your riding shoes, put the heel on the pedal, and see if your leg just goes straight when you pedal through the bottom of the stroke. This needs to happen with both legs equally. This affect power production, knee health, and the health of the rest of the connective tissue in the leg.

Bike fitters now have a lot of tricky methods for setting the saddle height, but the old test is still regarded as a good starting point, and most people and most shops don't really get this one right. But you don't need to be a pro to set this correctly for yourself, or to do it with a friendly assistant.

Second is whether your body clears the top-bar when you stop and put your feet flat on the ground. Because this is the easiest one for a shop to check, it's often all they do.

The foot contact with the ground when you are seated is less critical than the others in my opinion for an adult rider, because it doesn't affect riding quality or health like the first one does. Also because if you can get your feet safely on the ground by getting off the seat, you can get your feet safely on the ground. I think it's good for kids because it gives safety without any rider action needed to be taken. But not necessarily healthy for old knees, stressed knees, or knees whose owners are planning 20+ mile daily rides.

There are other saddle adjustments as well, but saddle height is regarded as the most fundamental one. Get that right with your saddle looking level in a side view, ride it a few days, then see where you stand (or sit).