Senior Member
Join Date: Apr 2009
Location: Boulder County, CO
Posts: 1,511
Bikes: '92 22" Cannondale M2000, '92 Cannondale R1000 Tandem, another modern Canndondale tandem, Two Holy Grail '86 Cannondale ST800s 27" (68.5cm) Touring bike w/Superbe Pro components and Phil Wood hubs. A bunch of other 27" ST frames & bikes.
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 110 Post(s)
Likes: 0
I, personally, am not at all a fan of the external bearing crank.
I talked to Leonard Zinn about this (his shop is nearby), and while there are some significant advantages that come with the external BB such as allowing for a larger bearing and thus a larger diameter/stiffer/lighter crank axle, the disadvantage of significantly increasing the Q-factor has to be considered.
I think its silly that all these years later after the Magic Motorcycle crank introduced the external BB, that it is just silly that BB shells haven't increased in size to allow the advantages of the larger bearings but only inboard. Using a vestige BB shell designed for square taper and compromising the fit of the bike with outboard BBs just makes no sense to me. Its one thing to retrofit, but new bikes?
I like the press fit Klein BB back in the day as well, for the same reasons.
I think Lightning is the only external BB Tandem crank being made longer than 180mm (goes to 200mm now). All the other long armed Tandem cranks are square taper if I'm not mistaken (Zinn/High Sierra, and daVinci).