Saddle positioning measurement

[sfscott]

Where are the points from which your saddle position is measured?

Additionally, I have some ruler-like measurements on my rails. How do these correspond to seat positions, and what do they refer to?

[Climb01742]

saddle height is from the center of BB to the top of the saddle. saddle setback is most often measured as the linear distance from the center of BB to the tip of the saddle (assuming you're using the same saddle.) finally, reach is measured from a point on the saddle (i use the back of the saddle) to the center of the handle bars.

[Ken Robb]

when we say saddle height we mean the distance from the center of crank to top of saddle. Other measurements are not as clear to me. I do measure from the nose of the saddle to the back-side of the bars to get an idea of relative reach on different bikes. Both of these measurements are affected by how far forward/back the saddle is mounted on the post. The marks on the rails are to help you know where you start position-wise and enable you to replicate it from bike-bike or after changing tilt. If you want to experiment with forward/back saddle position, and you should, it's good to record the positions as you try them and make notes so you can return to the best one after your experiments are over. I have found that small changes in saddle position, up-down, forward-back, and angle make HUGE differences in my comfort and performance. A broad generalization that is true for me: More forward makes high cadence easier but reduces my ability to push a big gear. I can't push over the top of the stroke very well when I'm sitting forward. I just put a shorter and higher stem on my full suspension mtn. bike replacing a 11cm 8degree up with 10cm 17 degree up. Big improvement in comfort and handling in sand and gravel as it is now much easier for me to unweight the front wheel and prevent it from submaring and hunting through the soft stuff. I can still easily get forward to keep the front wheel down on climbs.

[dbrk]

Setback properly speaking is measured from the point on the top tube that runs vertically through the bottom bracket to the center of the seat tube, not the point of the saddle. If Climb means "saddle set back" then that makes sense but it's the _frame's_ set back that determines the saddle position if you are seeking a particular knee and pedal position. Given the fact that different frames have different amounts of set back, the saddle would move accordingly---this makes using saddle set back a rather precarious method since, well, you need the frame set back first (and therefore foremost).
I hope this is clear.

dbrk

[sfscott]

Make sure your saddle is in the same place reach-wise when trying out different saddles?

Where is the best place to measure from if some saddles are of different lengths?

Also, does one take different saddle thicknesses into account on measuring height?

Just curious as I am PERFECTLY dialed in and want to be able to replicate that position if I change saddles.

[Climb01742]

douglas, i did mean saddle setback. i've personally found that, for me, the best way to replicate the same position from bike to bike, bikes with different STAs, is to begin by duplicating saddle setback and saddle height. measuring saddle setback isn't the easiest thing, but done well, its proven to be very useful to me lately in getting confortable on different bikes.

[dbrk]

Make sure your saddle is in the same place reach-wise when trying out different saddles?

Reach is critical, of course, because the slightest change can cause very different sensations but with different set backs on different bikes this features needs to be brought to account. So measure the _frame_ setback first because this determines your knee/pedal position and _that_ must come first. Then,

Where is the best place to measure from if some saddles are of different lengths?

Saddles are not only different lengths but different designs: some encourage you to sit all the way back, like a Brooks; some have wide backs, others skinny; some have long noses, others short. As I see this one, there is no fixed formula here, but look to the _stem_ to give you the proper reach once the saddle/knee position is established.

Also, does one take different saddle thicknesses into account on measuring height?

Measure from the rails to the top of the saddle using a straight ruler, add or subtract to get the saddle height within millimeters.

Don't be surprised if different saddles dial in to different positions. I sit on a B-17 in a position that is not much like the Regal or Rolls.
It's as much art as it may be math.

dbrk

[93legendti]

Make sure your saddle is in the same place reach-wise when trying out different saddles?

Where is the best place to measure from if some saddles are of different lengths?

Also, does one take different saddle thicknesses into account on measuring height?

Just curious as I am PERFECTLY dialed in and want to be able to replicate that position if I change saddles.

After many attempts, I found a system that works for me.

Saddle tilt:
I use a level to measure the tilt of my old saddle.

Saddle height:
I take a hex key, put it in the crank arm bolt and run a ruler from the hex up the seat tube and seat post. I have a straight edge on the top of the seat so I can find the true bb-saddle height.

Setback:
I take a plumb line and dop it down the center of the nose of the saddle and measure the effective horizontal length from the nose to the bb center. I check this measurement by using the tip of the saddle to the center of the handlebars as another measurement for setback. If the new saddle is a different length, I use the rear of the saddles as a measurement.

That being said, Serotta ihas a XY tool to make this easier!