HOW TO SET UP AND ADJUST YOUR SADDLE

FINDING YOUR BEST SADDLE POSITION

Saddle height will obviously vary from rider to rider, with leg length being the general determining factor.  However, two riders with the same leg length (often measured as inseam length) may need different saddle heights, due to differences in foot length, flexibility, crank-arm length, and pedaling motion.  It can be difficult to determine ideal saddle height on your own: leg length is difficult to measure accurately, and even an accurate measurement will only give you an approximate saddle height to work with [a general formula used in the past was 0.883 x inseam = saddle height].   Bike fitters will often use knee angle, as measured at the bottom [BDC, or Bottom Dead Center] of the pedal stroke, as a target for good seat height: many formulae state that the knee bend should be 25-35 degrees at BDC...i.e. a slight bend in the knee.  However, this is also an approximation, and a fairly large range to work within.  From a biomechanical perspective -- looking at leg motion from the side -- a good starting position is the highest saddle height that you can reach WHILE MAINTAINING SADDLE STABILITY (NO ROCKING OF YOUR HIPS SIDE-TO-SIDE ON THE SADDLE) and WITHOUT REACHING DOWN WITH YOUR TOES AT THE BOTTOM 0F THE STROKE. 

Too high a saddle can cause your pelvis and hips to rock side-to-side in order to reach the bottom of your motion; and/or it can cause your foot to angle downward (at the ankle) as it reaches the bottom.  Your hips should be stable on the saddle and your ankle should be in approximately the same angle all the way around the pedaling motion.  Another frequent symptom of a saddle that's too high: saddle pain or numbness.  If your saddle hurts and you suspect your seat might be too high, try lowering it a half inch for a couple of rides -- if your comfort improves, you may have found one reason for your saddle discomfort.  If your saddle is too low, you'll probably notice excessive leg fatigue, especially in your quadriceps (front thigh) muscles -- or even some knee pain.

The best way to determine perfect seat height is usually to consult a professional bike fitter who has a video recording system and knowledge in biomechanics. Be wary of any fitter who uses a predetermined formula (knee angle or other) to set your seat height -- proper seat height is best determined by looking at your pedaling motion (often in slow motion) and taking into account your flexibility, strength, and overall bike positioning.

Saddle height is usually measured from the center of the crank (front gears) directly up the seat post to the top of the saddle.  This is a convention used to be consistent, but ignores two factors: (1) crank length (from center of gears to pedals) is not taken into account; and (2) riders don't always sit with their sit bones right above the seat post.  If you change crank length, that will change the EFFECTIVE seat height, and might require a change in saddle position.

WHAT ABOUT SADDLE FORE/AFT?  DO SADDLE RAILS MATTER?

Ideal saddle fore/aft positioning can be one of the most difficult positions to find -- even for bike fitters.  Keep in mind that changing the saddle fore/aft position will also change the saddle's effective height slightly...meaning you'll have to readjust THAT to keep the same target height.  One method traditionally used to determine proper fore/aft positioning is called KOPS -- "Knee Over Pedal Spindle."  That method specifies that, when your foot is at the 3:00 position in the pedal motion (i.e. the crank arm is horizontal), the front of your knee should be directly over the center of the pedal -- fitters often used a plumb bob to find that position.  That method, although it might produce an approximation for many riders, has been widely debunked as an accurate measurement...and is no longer used by reputable fitters: fitters now use biomechanics and posture to find the best fore/aft position.  Still, it's clear that, in that 3:00 position, your knee should neither jut way forward of your foot (UNLESS you're on aerobars) nor sit behind your ankle.

So, what's the best way to find perfect fore/aft without a professional bike fitting?  A simple way is to start with the saddle positioned so it's clamped near the center of the seat rails.  If you find yourself sliding forward on the saddle while you ride, try moving the saddle slightly forward until you can stay in position while riding.  If you find yourself sitting on the back edge of the saddle, try sliding it back until your sit bones stay on the cushioned part of the saddle.  If you're experiencing knee pain, you may need the saddle to move back slightly; if your hamstrings are tight/sore after riding, you may need the saddle slightly more forward.

It's generally best to avoid positioning the saddle at the extreme ends of the saddle rails -- check for markings on your rails, which may indicate the limits for saddle adjustment.  If you find you need that much adjustment, you may need to change your seat post to one which extends back ("setback") more or less.  Also, some saddles do have slightly longer rails than others, allowing for slightly more fore/aft adjustability.

HOW MUCH SHOULD I TILT MY SADDLE?  HOW CAN I MEASURE IT?

By convention, most fitters measure saddle angle by placing a board or digital level across the entire saddle (front to back).  Again, this provides a consistent measurement system, but doesn't always measure the spot where you're actually sitting.  Although there is some personal preference in saddle tilt, it is almost always best to keep it LEVEL, or within a few degrees of level.  With a curved saddle, "level" may be difficult to determine: basically, you should LEVEL the area of the saddle where your sit bones are sitting.  With some curved/wavy saddles (like many Selle SMP models), that may mean the rear edge of the saddle is slightly higher than the nose.  If you tilt the nose too far down, you will find yourself (perhaps without realizing it) sliding forward on the saddle, and having to push yourself back to the comfortable spot on the seat.  If you tilt the nose up too far, you will probably feel excessive pressure on your perineum and genitals.  IF YOU HAVE TO TILT THE SADDLE NOSE DOWN MORE THAN 4-5 DEGREES TO BE COMFORTABLE ON THE SEAT, YOU HAVE THE WRONG SADDLE!!  Your goal is to find a tilt that keeps you both comfortable and STABLE on the saddle.