Seat height is set as a means unto itself. Bar position then follows.
In other words, do not manipulate your seat to achieve something else. Set your seat first.

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Totally get that, and that's fair, but let's assume I like my seat height as I sit currently. If I take spacers out, won't the new upper body position ultimately impact my lower body, especially as my ass moves forward on the saddle? And I would have assumed that by opening the hip angle up, you change your lower body angles in the pedal range. Basically tilting the torso forward and opening hips should in theory lengthen your leg, causing the saddle to be moved. Seems like a chicken and the egg scenario and that's where I'm stuck.

I can certainly understand in a road bike fit, start at the saddle, pedal/cleats then position the bars accordingly. I was just in a road position fitting and it was logical.

But for a Tri or TT fit, me personally - most important #1 is pads to pedals, and with it bars to pedals. Then from there you can slide in the seat in like a barstool. I mean if you look at the pros they are all over the saddle so how can the saddle be "it". makes no sense. And with some skill I've noticed that you can ride the Tri bike not even on the saddle (in the drops) if the everything is lined up & working nice.

It was even reported on here someone racing without a saddle - was that in the drops ?

So give it a go. Slam the bars - might need to reposition the pads etc forward a bit..

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If I take spacers out, won't the new upper body position ultimately impact my lower body, especially as my ass moves forward on the saddle? And I would have assumed that by opening the hip angle up, you change your lower body angles in the pedal range. Basically tilting the torso forward and opening hips should in theory lengthen your leg, causing the saddle to be moved.

Possibly. Some people advocate "rotating around the BB" which would mean that your saddle position *might* move up and forward slightly, if you drop your bars and extend the reach. That doesn't effect the hip angle but still changes your pedaling stroke because of the change in saddle to BB angle and gravity. If you pedal like you did before it will tend to push you forward. If you are a triathlete, then this might be fine, because I see a lot of pros with a forward saddle position.

Bottom line is that any changes will require adaptation, and there are many options. There is no hard and fast rule, and it sounds like the change you are considering is minor.

Short answer. Bars go down saddle goes forward and up slightly. if your happy with how the contact points interact your just trying to rotate everything forward.

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the amount of drop, just in a vertical axis, from the saddle to the aerobar pads is a function of:

1. saddle height
2. seat angle
3. cockpit distance
4. morphological "clearance."
5. crank length

let's get the easy part out of the way first. cockpit distance. if your cockpit is too long, you'll not be able to comfortably lower your bars. read this article for a quick tale of two cockpits. so, assuming your cockpit is appropriate...

the more forward your hips versus the crank, the lower you can go. here's a rule of thumb for pros and top AGers:

armrest drop = [(saddle height squared) x .005] - saddle height x .2

this is for someone riding at about 79° of seat angle, or whatever the equivalent would be if you're aboard a split-nose saddle.

so, me, 78.5cm of seat angle, that squared is 6,162 x .005 = 30.8cm.

subtract that from (78.5)(.2) = 15.7cm

30.8 - 15.7 = 15.1cm. i actually ride about 14.5cm because i just can't look forward any longer without being slightly up.

this formula adjusts based on whether you're more forward or more rearward. the more rearward you are, the higher the bars.

this is a "static" measure of armrest drop and should be subordinated to the output of a dynamic fit session, that is, if i fit you, while you're riding, aboard a proper fit bike, that would take precedence over this formula. the formula is just an expression of the mean of where top athletes ride, with a +/- variance. don't attach too much importance to this equation, and don't let the equation drive your decision. it's not meant as a driver of position, rather as an interesting coincidence, or expression of data.

then, clearance. what am i talking about? do you have a belly? if so, you've got a clearance problem. your thigh hits your belly at the top of the pedal stroke. bars have to come up.

crank length. shorter crank, all things equal, more armrest drop. why? read here.

what if you're NOT a pro or a top AGer? maybe you can't ride that low. what if your saddle is not comfortable when you're trying to ride that low? then don't ride that low. or change the saddle.

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Dan Empfield
aka Slowman

It's hard to tell from the pics, but it almost looks like your elbows are a little too far forward relative to your shoulders. Can't be sure without a side shot. But...

Your neck strength and flexibility will determine, to a large extent, how low the front end can go relative to the bar pads. Then your hip/low back flexibility will determine how far forward all of that needs to be relative to the BB. Saddle "height" is just a circle drawn with the BB at the center (very close to that, anyway).

For a tri fit, it's determined front-to-back.

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