Originally Posted by 531Aussie
CAAARMON!! Nobody says
that anymore.
I would say this is the current "doctrine":
"Popular Guides"
http://www.bsn.com/Cycling/cranks.html
..Height......Inseam.....Crank length
under 5'.....<=70 cm.....165
5' to 5'2"....<=74 cm.....167.5
5'2" to 5'7".<=80 cm....170
5'7" to 6'....<=86 cm......172.5
6' to 6'5"....<=93 cm......175
over 6'5"....<=99 cm......177.5 - 180.0
But they ARE saying it, and your chart proves it. 165 is only 3% smaller than 170, and 175 is only 3% larger than 170. I see the doctrine as "170 mm (give or take a tiny variation) is right for everyone."