Just switched from 172.5 to 167.5 onn the TT bike, while waiting for an official re-fitting in a few weeks whats the recommended 1st adjustment?
- Saddle height adj
- Saddle forward adj
- Stem adj
Thanks!
Saddle up and forward.
Saddle height goes up 5mm to keep BDC the same, saddle moves forward a bit (less than 5mm), stem length shouldn’t change much or be noticeable but you would extend forward it to keep the same back/arm angle. 5mm shorter on the crank should let you drop the bars 1cm or so and keep the same hip angle at TDC(5mm from shorter crank, and 5mm from higher seat). If you keep the bar height the same, it would open your hips up at TDC.
up and back
search and see all of Tom A’s comments wrt this
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Does Tom A do triathlons?
that is irrelevant
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Carlos Sastre moved his saddle up and back, to maintain foot position wrt the pedal on the down stroke. Yes, Carlos isn’t a triathlete. 
Personally, I don’t move the saddle forward or backward; the center of the foot’s circle is still the BB.
But I think there’s no scientific answer on this yet.
I went up & back to keep the relation during the power phase of the pedal stroke as close to the same as possible. FWIW.
Carlos Sastre moved his saddle up and back, to maintain foot position wrt the pedal on the down stroke. Yes, Carlos isn’t a triathlete.
Personally, I don’t move the saddle forward or backward; the center of the foot’s circle is still the BB.
On that one, Carlos got it right IMHO…the “return stroke” is less important than the “power stroke” portion of the pedal cycle. It’s just a way to move the foot back to the starting position to push again.
Think of climbing a flight of stairs. Don’t you tend to put your C.G. over your foot in the same spot regardless of step height (in a reasonable range of step heights, that is)?
For the OP, another thing he needs to indicate is what was the initial purpose of moving to shorter cranks? The answer to that one can determine what other adjustments to contact points one may want to make.
Does Tom A do triathlons?
I have participated in those events, yes (Well…OK…as part of a relay ;-)…But, I did a run-bike-run duathlon way back in 1987. Does that count? 
Moving from IM distance to Oly distance and road race TT’s this yr, focus is more on optimizing ride performance at the shorter distances.
Moving from IM distance to Oly distance and road race TT’s this yr, focus is more on optimizing ride performance at the shorter distances.
Right…and how were you expecting the shorter crank length to help in that regard?
In other words, are you looking to open up the “clearance” between thigh and torso at the top of the pedal stroke…are you looking to be able to lower your torso and maintain the same clearance…or, something else?
Varying crank length is a fitting tool. What fit “challenge” were you hoping to address? The answer to that will determine the other changes (and directions to them) you may want to also do along with the basic saddle vs. power stroke adjustments.
IF shorter cranks allow a greater hip angle at the top, then i am expecting to get a more aero postion from saddle to bars. My assumption is that i will be raising (potentially forward too) the saddle and potentially lowering stem/bars and still be able to keep or improve hip angle (assuming it needs). Potentially. I feel its worth testing out now vs later in yr.
I went shorter by 3cm on my cranks and love it. Don’t expect any power increase, but I find the new position with a lower front end and less leg movement much more comfortable and maintainable. I would imagine running will be better over the first few miles as my hips won’t be as tight. I don’t see the harm in trying new things, and if they don’t work out then switch back.
veteran then…