Originally Posted by
datlas
Interesting. Assuming saddle height is based on full leg extension, one should adjust this for cranks. Ditto saddle fore/aft, and hence stem length, if you want to keep the same “fit” with shorter cranks.
I realize this is not a rigid geometry issue, but hypothetically if you want same positions you would need to adjust all three of these.
This is the very assumption that this fitter was questioning. Some riders are limited more by their knee/hip angle at the top of the stroke, so they may be compensating for this by raising their saddle above their optimum for leg extension. Another prominent UK fitter said that most riders who came to him had their saddle set far too high (typically 10-20mm too high!).
So shorter cranks give you a wider fitting window for both leg extension and compression.