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Guest
*Seems* like it's critical to a proper fit.
My body finds KOPS and my sit bones wind up somewhere depending on that. I can move them a little
backward and a little forward by varying the tilt of my pelvis - but mostly their position is locked
in by my other body dimensions and the fact that my body tends to position itself so that my
kneecaps are roughly over the pedal spindles.
To get a saddle where my sit bones are one needs a certain range of saddle clip adjustment - which
is constrained by seatpost setback and the length of the straight portion of a saddle's rails.
Sounds logical, right?
But if it's so logical, why don't makers specify setback in their frame geometry specs?
http://www.jamisbikes.com/bikes/spec_geo/03_steel_geo.html is typical. Lotta measurements there, but
nothing to tell me if my butt is going to be resting on the horn of the saddle, the rear edge of the
saddle, or some less-destructive place in-between.
Granted the fore-aft position of the saddle relative to BB changes as the saddle is raised/lowered -
but that change could easily(?) be computed given the seat tube angle.
SO, bottome line, why doesn't anybody talk about "setback" in the context of frame dimensions?
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PeteCresswell
My body finds KOPS and my sit bones wind up somewhere depending on that. I can move them a little
backward and a little forward by varying the tilt of my pelvis - but mostly their position is locked
in by my other body dimensions and the fact that my body tends to position itself so that my
kneecaps are roughly over the pedal spindles.
To get a saddle where my sit bones are one needs a certain range of saddle clip adjustment - which
is constrained by seatpost setback and the length of the straight portion of a saddle's rails.
Sounds logical, right?
But if it's so logical, why don't makers specify setback in their frame geometry specs?
http://www.jamisbikes.com/bikes/spec_geo/03_steel_geo.html is typical. Lotta measurements there, but
nothing to tell me if my butt is going to be resting on the horn of the saddle, the rear edge of the
saddle, or some less-destructive place in-between.
Granted the fore-aft position of the saddle relative to BB changes as the saddle is raised/lowered -
but that change could easily(?) be computed given the seat tube angle.
SO, bottome line, why doesn't anybody talk about "setback" in the context of frame dimensions?
-----------------------
PeteCresswell