This is a really good post. However, there is a lot of differing opinion about bike fit, and everyone has a favorite saddle. (One or more. I have two, one for commuting, and another for riding fast and far. The "fast and far" one has less
My thoughts/clarifications/commentary inserted...
Originally Posted by Silverexpress
Whatever saddle you get make sure of 3 things...
1. Make sure your "SIT" bones are supported. Take a measurement of the distance between these two bones, and make sure that whatever saddle you get is wide enough to support them. Don't go to wide or else you'll restrict your movement or induce chafing in your inner thighs.
Absolutely critical. You may be OK right now on this score, depending on where it hurts. If you have two distinct points of pain, one on each posterior cheek, that hurt more when you sit on a hard flat surface, and the pain is deep you may be OK for the saddle design and fit (or pretty close), you just need to get accustomed to longer rides.
If it hurts more "in the middle", you've got a problem, but the solution may still lie in seat adjustment, so read on.
2. Make surethe seat is adjusted properly
There are three more things to look for in detail.
A. Height: adjust it so that you have a slight bend in the knees when your
foot is parallel to the floor Also take note that it is the ball of your foot that
should contact your pedals. You do this by placing the crankarms directly
vertical of the floor. With a foot on the lowest pedal take note of the bend in
the knee. Again, it should be a slight bend; in fact, you should start with the
seat too high and then work your way done about 1/8 of an inch each time.
You'll know it's too high when your butt moves side to side as you try and
reach for the pedals. Also you'll hyperextend your legs. You don't want your
butt moving side to side.
You also don't want to have to point your toes, your ankle should be in a comfortable neutral position.
Lower the seat in increments until you have just a
slight and comfortable bend in both knees, and when you pedal your butt
stays firmly seated.
You can get pretty quickly into the ballpark by doing as above, but putting your heel on the pedal. Then adjust up or down from there. It's just another "rule of thumb" way of getting close to start with.
B. Fore & Aft - after doing the above make sure a knee is directly above your
pedal when the crankarms are placed horizontal to the ground. If it falls
behind the pedal, then you need to move the seat forward. If it falls
forward the pedal, you have to move it backwards.
The "knee above pedal" thing (sometimes called KOPS or "Knee Over Pedal Spindle") is another "rule of thumb" that will get you in the ballpark, it is not
an absolute truth. If you find yourself sitting forward toward the "nose" of the seat (so that your sit bones miss the wide part of the seat), move the seat forward. If you feel "crowded", move it rearward. Not much, 1/4 to 1/8" at a time.
C. The seat is level. Once you've got the above mastered, ride the bike
around and see if your either sliding back or forward on the seat. Adjust
the tilt accordingly so this does not happen. This may affect the above so
you might need to go back and readjust...
Or just measure it with a level. The idea is that it has to be horizontal in order for you to sit on it. Nose-up, and you'll put pressure where it doesn't belong. Nose-down, and you'll be sliding forward, missing your sit-bones, and putting pressure where it doesn't belong. I would get the seat level before
worrying about fore-aft.
3. The third thing to make sure of is the type of seat: There are many. From my own experience; the cushier, the worst. If it's gel, the fluid often times gets squished out from where it should be over time. If it's padding, it wears out overtime and your sit bones will be resting on the hard unforgiving plastic shell. Get rid of that comfort seat.
Actually, the worst thing about "cushy" seats is that the padding tends to wad or push up between the "sit bones", putting pressure where it doesn't belong.
Also remember that the fore/aft adjustments effect the seat height as well (since the pedals stay in the same place, moving the seat forward makes the distance from the pedal to the seat a little shorter.) Measure the height that works with a tape measure, and use that measurement, rather than a mark on the seatpost.
The final thought from this quarter is that, as you ride more, and get better at riding, the adjustments may change. You body musculature will change, perhaps only a litttle, and you find that a seat position that was fine at the beginning of the year is now not comfortable anymore. Listen to your body and adjust accordingly.