Seatpost length, how to measure?
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Seatpost length, how to measure?
Obviously one of the points is the bottom end of the post but where is the top measure taken, at the rails, extreme top?
#3
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useful length is less than total length of course.. you need to have the bottom inside the frame
far enough to span the width of the top tube joint to the bottom of it.
far enough to span the width of the top tube joint to the bottom of it.
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What you are measuring is total length. Useful length for most seatposts requires the minimum insertion mark to be at or below the top of the seat tube so the useful length is total length minus about 60 to 75 mm. Another exception is the Thomson "Set Back" (i.e. bent) seatpost where the bend must be above the top of the seat tube.