This article is from the Bicycles FAQ, by Mike Iglesias with numerous contributions by others.
From: Jobst Brandt <firstname.lastname@example.org>
Date: Mon, 10 Jul 2000 16:09:46 PDT
I'm not familiar with BB drop. How is it measured and what are its
For road bicycles, using conventional sized wheels, BB drop (BB
spindle centerline below wheel axle centerlines) has been empirically
arrived upon at about [240mm minus crank length] for useful cornering
clearance. Imbalance of pedaling in curves at greater lean causes
side-slip. For this reason, higher BB's have shown no advantage in
criterium racing while road races are practically unaffected by
maximum cornering ability while pedaling. Track bicycles have certain
advantages on tracks with low banking if they can ride the curves at
zero speed but then that depends on track length and how it is banked.