It seems when I fit experience triathletes, the numbers are very predictable. But when I have new athletes, they are just not comfortable going to the predicted armrest drop

Example : Seat height 77 cm, Seat angle 78, and a predicted drop of ~11, but... the client could only tolerate a drop of 7 cm.

So if I try to calculate Stack and Reach from bar bore x, y, Stack will be too big.

What is the best way to compensate for this arm rest drop so I can make a bike recommendation to a client?
pedestals under the armrests. maybe look at these articles

evil stems and spacers
zipp vuka alumina

Dan Empfield
aka Slowman
Thanks Dan for the reply. Yes, I agree with the spacers and such, but my question is more about calculating Stack and Reach for a client.

Question : if the client has a calculated armrest drop of 11 cm but can only achieve 7 cm. This delta would throw off Stack if we use the 7cm position. Right? So do we calculate Stack for the client using the 11cm and add the spacers and such?
don't worry that much about calculated armrest drop. it's a guide, it's not a driver. now, let's say that 11cm of drop would give you a stack/reach of 540/430, based on a -6° stem, 15mm headset top cap, no spacers.

but let's say you can only get 7cm of drop out of the fit. then the stack is 580. but let's say that it's just not really possible or optimal to get 580mm of stack, maybe you don't have that bike available to you, maybe you have it but the customer doesn't want it. you have to get that height some other way.

method 1: go to a stem with a steeper pitch. not my favorite idea.
method 2: headset spacers. not my favorite idea. unless that's the way the frame is designed, as in a P5 or a BMC TM01. then, more acceptable.
method 3: what is the profile of the aerobar? low profile, as in something with the top of the pads 3cm or 4cm above the centerline of the pursuit bar? choose a higher profile aerobar.
method 4: if your aerobar is the kind where you pedestal the pads and extensions as a complex - as a unit - then this is a great way to get that height. felt's new aerobar, bontrager's aerobar that goes on the speed concept, profile's new T1, the zipp vuka alumina clip, all are made this way. this is quite okay. just make sure you don't have a descending pursuit bar, that is, the pursuit bar should be flat, not angled down, because the height gap between the pads and pursuit position will be too great.

Dan Empfield
aka Slowman