Mountain Bike Saddle Position Help
Fore/Aft saddle position
Please set the Fore/Aft saddle position before
you set the saddle height as viewed to the right.
Fore/aft position is measured from a line (laser/straight edge) that bisects the (center
of bottom bracket) and runs up bisecting the top and center of
seat post, past the top of the saddle in space to the top edge of a (Stanley PowerLock 8m/26') 24mm width tape. It is very important to use a 24mm width tape, as that tape size is how we came up with our CAD measurement constraints. (see photo on lower
right using some kind of straight edge on that line), back to the
"sweet spot" of the seat. The "sweet spot" is where the back
of the sit bones make contact with the "leading edge" of the saddle - in most cases, is the widest part of the saddle as view
by the photo on the top. The forward sticker in the center represents
where the straight edge crosses the top of the saddle, bottom photo.
This may require replacement of the seat post or saddle to obtain
the proper position for your shape. The shape of replacement seat posts may be
neutral, or aft. Please note that some saddle's don't allow for enough
rail adjustments. Saddle width can become a issue, we suggest the most narrow. You don't want the inside of your legs brushing on the saddle.
After the saddle has been positioned you need to now make a adjustment
to the saddle tilt for that person. You want to tilt the ASIS hip down and forward, this will vary according to one's obstructions, also to feel some tension to your hamstrings. For most road saddles, that is level to 1.5 nose down and mtb starting at 1.5- or more degrees nose down for the sag from where the level is on the nose & where the level hits one of the sit bones areas. Press firmly, to compress or deflect the top of a given saddle. If needed you can move (tilt) more or less level saddle as needed for soft tissue and lower back flex. By changing the tilt, you change the reach, the back of the saddle makes the leg longer in reach. We don't want to have the saddle too far from the pedal and we don't want too much pressure on the hands.
Place some kind of a straight edge (book, level, ruler, etc.) on
top of the saddle and view the running edge from the side. For most saddles, you should
see some daylight under the straight edge and we call that empty space
the "hammock". This will also allow you to view the saddle angle.
For mountain bikes a nose down 1.5 to 2.5 degrees allows you to
have more comfort, be stronger for steep climbs as your sit bones bridge and rest towards the rear of the
"hammock area". This takes pressure off the front of the hammock
area and allows you to climb better. With full suspension bikes,
you want to sit on the bike with the "payload" your upper body weight
mostly on the saddle. This places weight on your saddle, seat post, and
rear shocks. Balance and comfort is the key here and we don't want
you sliding forward.
Saddles are very different today e.g. They are more flat, i.e. Fizik has 3 very different types, so use your best judgment, this means the
tilt could vary with shape, softness etc. You goal is you don't want to much weight on
your hands from the nose being tilted downward too much. And you don't
want your nose up too much, because that will place more pressure on your
forward anatomy and place stress on the lower back (L5- S1) when doing hard efforts or climbing steep hills.
After you determine the tilt and the fore and aft then you set
the saddle height. The lowest part of the "hammock" the space under
the straight edge will be in most cases the place to measure to
the sit bones. This is a constraint that you don't want to go higher in saddle height. Please note that if you tilt the saddle more level, you are increasing your leg reach. If needed, start below and have the person adapt towards the CAD saddle height!!!
Use the Saddle Height output from the Measurement
Results. The Saddle Height is your power transfer, determined by first placing the right
pedal so the crank is in line (parallel) with the Seat Tube.
Next, measure from the top of the platform of the pedal system,
in the center, to the top of the saddle surface on the centerline with the
Seat Tube. Please note that the width of the saddle will affect this measurement (its on a angle from the pedal to the edge of the nose of the saddle forward of the leading edge).
Click on the picture to the right for a bigger view.
Score Your Seat Post!
After you have set and tested your saddle height
you should score or mark the seat post with permanent marker, tape, etc.. The saddle/seat post can be returned to
its proper height if you take your bike apart for travel.