This is a pretty good representation of the before and after (more precisely it's after and before, left to right). the changes were as follows:
1. the "new" jens has a saddle 2.5cm higher.
2. the new and old jens have virtually the same armrest drop, old being 18cm, new 17.5cm
3. nevertheless, jens' hip angle differs between the old and new. the new jens has a hip angle (using my landmarks) of 100°, dead on. the jens-stretch has a hip angle of 97°. the reason is that jens-stretch has armrests sitting 8cm further in front of the saddle, and this places his upper arms at an angle, lowering his front end and making his hip angle more acute.
my guess: unquestionably, in my mind, jens' saddle was too low. but jens-stretch's more acute hip angle may have resulted in hamstring-stretch, mandating a need for a lower saddle height. even accounting for that, i think the saddle was well lower than it ought to have been, and i'd be very surprised if the saddle on his road bike was that low. but it's hard to quantify -- it's hard to measure apples to apples if your road bike has a standard saddle and the TT bike an ISM adamo. the way to check would be to use a goniometer and look at knee angles. in any case, i think the low saddle has more to do with lost power than anything else.
jens-stretch is undeniably more aero than jens-compatto, but i don't know how much. can jens-compatto do something about that head sticking up? would jens-stretch with higher saddle get the watts back? would jens-compatto get more watts back? would jens-compatto get more watts than he'd lose in negative drag-adjusted-watts? i suspect we'll hear more after jens does some field tests.
Dan Empfield
aka Slowman