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Quick Q? What's considered a high or low BB? (n/m)(3 posts)

Quick Q? What's considered a high or low BB? (n/m)timfire
Oct 28, 2002 1:46 PM
--Timothy Kleinert
re: Quick Q? What's considered a high or low BB? (n/m)Fredrico
Oct 28, 2002 2:49 PM
DeRosa and Sachs have put BBs as low as 7.5cm dropped from the center line of the front and rear axles. It explains some of the mystique of these makes: putting the crank low stabilizes the ride.

More typical is a 6.5cm drop, which gives a bit more clearance for the pedals. Mountain bikes might be higher.
General rule of thumbNessism
Oct 28, 2002 4:03 PM
The most common figure is approx. 7.0 cm of bottom bracket drop. BB drop is a good way of looking at BB height since it takes tire diameter out of the equation. To my mind, frames with less than 7.0 cm drop have "high" bottom brackets while "low" bottom bracket rigs are in the 7.4+ cm range. You will find very few frames with bottom brackets lower than 7.4 cm, a few that come to mind are Serotta, Moser (I think), and of course Richard Sachs (he uses about 8.0 cm for the most part).

Good luck.

Ed