Standard reference point for saddle height measurement
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Standard reference point for saddle height measurement
Sorry to start a thread with such an obvious question that likely has been answered dozens of times, but here it goes....
When measuring a bike fit, what is the standard reference location on the saddle that should be used to measure the saddle height?
I am trying to match the fit on two road bikes with different seat tube angles. Fortunately, they have identical saddles - that helps.
So, measure from the bottom bracket up to....where?
It seems like the most easily located spot is the saddle nose, but I've never seen a geometry chart that suggests it. I've seen the method from pbmcoaching.com that suggests measuring the place where the saddle width is 80 mm. And I've seen (not sure where) a suggestion to measure from 60% of the distance from the front to the back of the saddle.
Suggestions? Or a pointer to a standardized reference or chart?
Also, is there any reason not to do it simply by measuring the vertical (plumb bob) difference (floor to the saddle top) - (floor to bb)? Combined with a horizontal measurement between the bb and the saddle nose, that should be the most general, no? But it's not what I have seen in charts and tutorials.
Thanks
When measuring a bike fit, what is the standard reference location on the saddle that should be used to measure the saddle height?
I am trying to match the fit on two road bikes with different seat tube angles. Fortunately, they have identical saddles - that helps.
So, measure from the bottom bracket up to....where?
It seems like the most easily located spot is the saddle nose, but I've never seen a geometry chart that suggests it. I've seen the method from pbmcoaching.com that suggests measuring the place where the saddle width is 80 mm. And I've seen (not sure where) a suggestion to measure from 60% of the distance from the front to the back of the saddle.
Suggestions? Or a pointer to a standardized reference or chart?
Also, is there any reason not to do it simply by measuring the vertical (plumb bob) difference (floor to the saddle top) - (floor to bb)? Combined with a horizontal measurement between the bb and the saddle nose, that should be the most general, no? But it's not what I have seen in charts and tutorials.
Thanks
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Measurement of various points on the saddle, say the nose or in line with the seat tube, can introduce quite a bit of variability to the measurement. For that reason I locate the widest part of the saddle on the reasonable assumption that is the location of the sit bones and will always be located there no matter the saddle. It is true we may slide forward, (on the rivet) when really hammering away but that is not our regular position.
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I assume you have considered the fore aft positions and crank lengths on both bikes as being the same?
Cleat position will also affect your saddle height...
Cleat position will also affect your saddle height...
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Same length cranks (172.5 mm) and it's the same rider wearing the same shoes, so those are already equal.
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I measure to where my bones contact the saddle, so either ichial tuberosities or pubic ramus, however you perch on your saddle. There's really not another way. Align the cranks with your tape measure, measuring from the center of the pedal axle to the specified point on the saddle. Which of course only works for transferring saddle height measurement from one bike to another. Initially one can start with a formula or heel-on-pedal and modify by feel.
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I measure to where my bones contact the saddle, so either ichial tuberosities or pubic ramus, however you perch on your saddle. There's really not another way. Align the cranks with your tape measure, measuring from the center of the pedal axle to the specified point on the saddle. Which of course only works for transferring saddle height measurement from one bike to another. Initially one can start with a formula or heel-on-pedal and modify by feel.
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Yup. Can't improve on that.
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I just measure straight up the seat tube and seatpost to where it intersects with the saddle.
Then nose of saddle to bars.
Seat-tube angle will impact saddle setback I would think.
Then nose of saddle to bars.
Seat-tube angle will impact saddle setback I would think.
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I simply measure form BB to center of saddle. I would think finding EXACTLY where your sit bones are would be rather tricky. (I think measuring to the widest point would be better than that.) In any case, the main thing is to do it the same way every time.
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In line with the seat tube, measuring either from the BB for those who use the Lemond Method or from the pedal axle with the pedal rotated to align with the seat tube.