This is pretty obvious and your post indicates you kind of already get it, but you need to match the saddle stack and reach (or height and setback) AND the bars stack and reach. So you measure both and match both. Matching both makes any two bikes fit basically the same (handling may still be different).

If you can't match the saddle stack and reach, you can't fix it by simply changing saddles because saddles are different shapes. For a given saddle setback, the Adamo has your butt sitting about 6.5cm in front of where it would be on a normal saddle (if you actually sit on it normally which not everyone does). So sure you can get a normal saddle to have a farther forward setback than the Adamo, but your butt still won't be in the right place.

Instead, you have to fix it using the seatpost. Most bikes have a way of doing this. Either you can reverse the seatpost, or in some cases (Cervelo) you buy a separate seatpost with two holes in it, one of which is farther forward and will get you where you want. I don't know the 4000. Maybe someone here does or your bike shop does. There's usually a solution though.

It doesn't account for it, but to be fair neither do traditional frame dimensions.

Attainable saddle fore/aft is a product of seat tube angle, post extension, clamp setback, and saddle rail length. In the past you could get a different seatpost and get pretty much any saddle position you wanted. The advent of dedicated posts crates some problems, especially if it lacks flipability or adjustable clamp placement.

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ECMGN Therapy Silicon Valley:
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Saddle stack and reach is not something I saw on Slowman's stack and reach chart, nor is it anything I have seen on manufacturer specs, maybe I've missed it, or is it called something else.

I'm aware of how to sit on the Adamo and I am sitting on it properly, and changing saddles actually did fix it somewhat. The Cobb saddle prongs are longer than the Adamo's and the rails under the saddle are different allowing it to get closer to the BB. The Cobb is just slightly different width.

I'm not aware of any other seat post for the Kestrel's.

I'm good now with what I have, but I was curious just incase I do decide to buy.

There is no saddle stack/reach dimension for bikes (since the amount of seatpost extension would change this, and a stack/reach for the seatpost clamp on the frame wouldn't be too useful).

For fitting, people usually use seat height (measured as a diagonal line from the either the BB or the pedal platform up to the middle of the seat), and setback (how far the nose of the saddle is behind the BB). Notice that these are ergonomic dimensions of the rider's position (like pad stack and reach), not an inherent attribute of the frame.
In theory you could have a range of seatpost clamp positions that the frame/seatpost could support. It would be a diagonal line parallel to the seat tube (or multiple lines for flippable posts), and very hard for people to use to determine frame fit.

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ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)

Stack and reach are frame size measurements, and pertain only to the front end. The saddle position isn't usually an important frame size measurement since there is a huge efficient range of height and fore-aft adjustment. Easier than getting the front end right. Basically, you just put it where you want it (x,y relative to BB). But you need to make sure that where you want it is in the bike's (huge) range of adjustment.

That is true, I completely forgot about that, but this does bring me back to my original Kestrel 4000 scenario.

The 4000 has a steeper advertised seat angle per manufacturers specs than the Airfoil so I though I would be good, yet I could not get it over the BB like I could on the Airfoil.

Not sure how I can get it over the BB on a size 56 and 59 Airfoil with advertised forward seat post angle of 78.3 but not on the 4000 with advertised angle of 79.

Of all three bikes the seat post on the Airfoil 56 came out of the frame the furthest so in theory you would think would have been the furthest behind under the farther you raise it, the further it is behind the BB theory (angle depending).

I guess another thing to consider is where do the measure this angle? If the seat post comes out of the frame at a 90 degree angle, the higher you raise it, the steeper the angle will be, or if it comes out at more of an angle, like you say, it will get further and further behind the BB and depending on that exit actually get more and more slack angle.


But still in the overall method of finding your stack and reach, and then finding a bike that matches this stack and reach number, no where does it mention saddle setback so how do I know?

There a few bike out there I like that match my stack and reach, but when I look at the seat post I can see there is no way I could get the front of the saddle right over the top of the BB.

The Giant is a perfect example of that. This Adamo seat looks to be almost as far forward as possible, but still would be maybe an inch behind the BB depending on seat height. Other than that stack and reach measurements would fit me.

But my point is not all bikes have a huge range of fore aft adjustment on seat. Reading about stack and reach fitting it says once you find you stack and reach you can easily find your bike by looking at the stack and reach chart.

None of this accounts for saddle setback, or possibilities, and not all bikes offer optional seat post etc. The BMC bikes are also close to my stack and reach numbers as well from what I can remember, but looking at them, saddle setback behind the BB just looks to great for me.

Perhaps I'm a bit odd for wanting it that steep.

This is a rough pic, but this is from my 4000 with Adamo. Saddle clamp was as far forward on rail as possible, and mounted as far forward on rail as possible. I actually removed a mounting screw from the slide mechanism to get it about .5cm further forward than it would go too. Not sure if that is recommended, but it held. Switched to Joff and it wasn't as bad.

Like I said I'm looking at new bikes, but even if I find the correct stack and reach, I'm afraid I wont be able to get the saddle seat back from the BB where I want it.

Again sorry for the rough pic, couldn't find my plumb bob either but check the yard stick with level for pic. Thats at least an inch behind the BB, probably closer to two.

This is a more clear close up of the 4000, to show it is as far forward as I could get it, still about an inch behind BB as measured with plumb bob. Adamo is even worse.

Don't have this problem with the Airfoil.

And hoping not to have it with future bikes................ but since it isn't a given spec...... and stores don't have bikes in stock around here..... how does one know if it will work? That's what happened with the 4000. Hoping not to have it happen again.

Don't think anyone said stack and reach was everything. Apparently your saddle position is outside the range some manufacturers consider normal. Seems like a goof on their part. Right over the BB shouldn't be weird.

There's a super old review of the 4000 on slowtwitch that talks about seatpost issues. It claims there was a seatpost redesign that gets you more forward. I don't know how dated that information is, but it might be something to ask about.

I've tried to collect info to be able to include STA viability in our bike finder. Can do it for a few brands where the true STA is known along with seatpost fore and aft movement ranges.
But haven't been able to get specs for enough brands to justify including it in the system.

Trying to get an ISM level with the BB puts you very steep - well past 80deg effective STA. So you're out of the zone that manufacturers are designing for and few bikes will suit.